tag:blogger.com,1999:blog-77545111326729549182024-03-18T11:20:15.591+01:00it's a clean machinethings we've made and seenAnonymoushttp://www.blogger.com/profile/11894544550052182034noreply@blogger.comBlogger128125tag:blogger.com,1999:blog-7754511132672954918.post-27958298019770410762013-10-26T23:31:00.000+02:002013-10-26T23:31:01.384+02:00Conserving screen space in GNOME<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwJB_MxMdkJyaYeB0z5AItJUahkGre38s8KKHoy4190mLvDr2lsU0yftlx0D8q6YC13hHMTMAHS1hl-ZmpzY5ksNfB3v9R0PlspOQWXixjC9-znWTgKerb5hdwkOaOl4UjASuO1rrMhyphenhyphenW7/s1600/before-after.png" /><br />
<br />
I finally found a tool to accomplish something I have wanted for a long time, namely tuning the size of icons and buttons in Gnome. Gnome applications waste a lot of precious screen space by default, probably the default settings are developed for and by people with six HD monitors at their desks. On a tiny screen such as the 1024x600 screen in my eee-pc, pixels are precious and should not be wasted.<br />
<br />
The tool I found is called <span style="font-family: Courier New, Courier, monospace;">gnome-color-chooser</span>. Install it with<br />
<br />
<span style="font-family: Courier New, Courier, monospace;">sudo aptitude install gnome-color-chooser</span><br />
<br />
I should say that I'm using Linux Mint Debian, with the Mate desktop based on Gnome 2. Gnome 3 appears to be configured differently, judging from a quick search.<br />
<br />
The color chooser tool allows you to choose the colors of different elements, but it has several settings for button sizes and icon sizes as well. First, let's set all paddings to 0, except the y-padding of widgets which I chose to keep as 1. Check <b>Use shadowless Menubars</b> and <b>Use shadowless Toolbars</b>. On the <b>Icons</b> tab, you can set icon sizes. I set the sizes to 14-12-12-12. I particularly liked the setting <b>Start menu</b>, setting it to 12 pixels made the menu small, nice and manageable.<br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgTyvJyaTrIzOxoIS1SHFMben3JlXin8mlN7GOyi9I0cim6gfC7IqdYL2BpZkqsgBSIzjTu-GoAjmhFzQA-upIdwnnpwqW-Ql6lvAETJ0Hn4GRNIhvWWobB0k1CxTTvobrWdw37HvkH2rN0/s1600/colorchooser.png" /><br />
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What the tool actually does is to provide settings in a file included from <span style="font-family: 'Courier New', Courier, monospace;">.gtkrc-2.0.</span><br />
As the <a href="https://wiki.archlinux.org/index.php/GTK%2B" target="_blank">Archlinux Wiki</a> points out, one can also modify the <span style="font-family: Courier New, Courier, monospace;">.gtkrc-2.0</span> file by hand.<br />
<br />
Other settings to change for a compact look:<br />
<ul>
<li><b>System</b> > <b>Preferences</b> > <b>Appearance</b>, <b>Fonts</b>-tab, <b>Details</b>-button. Change <b>Screen resolution</b> from 96 to 80. For some reason, this setting works better than changing the font sizes.</li>
<li><b>System</b> > <b>Preferences</b> > <b>Appearance</b>, <b>Themes</b>-tab. <b>Controls</b>: Clearlooks, <b>Window borders</b>: Mint-X, <b>Icons</b>: Gnome</li>
</ul>
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhYYT0uTe-MG7aaMTckczTfX_-7PyM0z1-lPr0bm0dqs4exAT743AAWaSK_ssVrWS9vZhRpWmYh367gwIof6YFLGPjwO80vPwpKYQSkVY4yym052I-FUGbbhPNf3NANMo12DK22hzP1l2yK/s1600/fontrenderingdetails.png" /><br />
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While at it, fix the file manager preferences:<br />
<ul>
<li>View new folders using: Compact View</li>
<li>Compact view defaults, Default zoom level 66%</li>
<li>Uncheck <b>All columns have the same width</b></li>
</ul>
With the latest update pack for LMDE, many application started to display the following warning when run in a terminal. I frequently launch emacs from a terminal to edit files, then the message clutters up the terminal.<br />
<br />
<span style="font-family: Courier New, Courier, monospace;">Fontconfig warning: "/etc/fonts/conf.d/53-monospace-lcd-filter.conf", line 10: Having multiple values in <test> isn't supported and may not work as expected</span><br />
<br />
A quick fix to get rid of this annoyance is to comment out line 10 of the offending file:<br />
<span style="font-family: Courier New, Courier, monospace;"><!-- <string>Bitstream Vera Sans Mono</string> --></span><br />
I figure this might change something, but it looks that the file was broken anyway as it was shipped.Anonymoushttp://www.blogger.com/profile/02726645543851535178noreply@blogger.com2tag:blogger.com,1999:blog-7754511132672954918.post-40282544957660645042013-10-20T10:00:00.000+02:002013-10-20T10:00:01.515+02:00New disk for an old eee-pc<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLEd6tUxyfwKYJ7bxCsRC1CuwW4IFbJOi-p54JIJsy8Zeo_63XWHtF-PIiOYX2JL-CS0DzoXum6uGJxaQ6f9KWbXtzyH_95ldZU9KF0zDhXf7Zh8J4HxkQAk7072DPJHy1VjtU5BLW_bSu/s1600/eee1.JPG" /><br />
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Our trusty eee-pc 901 was getting slower and slower. The 16G SSD in it was not very fast to begin with, but has definitely become slower over time. To keep the otherwise nice laptop running for a few more years, I decided to upgrade the SSD. The drive I ended up buying a 64G <a href="http://www.amazon.com/gp/product/B002EJ6N38/ref=as_li_ss_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B002EJ6N38&linkCode=as2&tag=itsacleanmach-20">Super Talent FPM64GLSE</a>. RunCore disks have a reputation for being faster, but they were also more expensive and hard to obtain. The eee-pc requires a PCI-E disk. There are also newer mSata disks available. These use a physically similar connector as PCI-E, but are not compatible.<br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXdmdhrzG3ij-OSfYqGJtPg-nAnGdiEsPmG4Gv6axZKXS6raMkn0fLrzblxihfSMQ5ulpDTFabxipcDqGbfYqxXoOA82jSEGjWNAsnsMP0bidtJdhMgRS6X2NQkz-vtdZiSFiNP7AIU6Oy/s1600/eee2.JPG" /><br />
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A quick test of the Super Talent with <a href="http://iozone.org/">iozone</a> yielded the following results, in KB/s. The same settings were the same as when measuring <a href="http://itsacleanmachine.blogspot.com/2012/08/sd-card-benchmark-on-raspberry-pi.html">SD card performance</a> on the raspberry Pi earlier,<br />
<span style="font-family: Courier New, Courier, monospace;">./iozone -e -I -a -s 50M -r 4k -r 512k -r 16M -i 0 -i 1 -i 2</span><br />
<br />
<span style="font-family: Courier New, Courier, monospace;"> random random </span><br />
<span style="font-family: Courier New, Courier, monospace;">reclen write rewrite read reread read write </span><br />
<span style="font-family: Courier New, Courier, monospace;"> 4 17258 20110 12626 12623 12528 1457 </span><br />
<span style="font-family: Courier New, Courier, monospace;"> 512 74590 41339 127710 127909 121887 74354 </span><br />
<span style="font-family: Courier New, Courier, monospace;"> 16384 40403 75312 129705 129748 130483 40077 </span><br />
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As with SD cards, the speeds that the manufacturers specify is the rate of sequential reading or writing of large contiguous blocks (Reading max 150 MB/s, writing max 100 MB/s is what they specify). Randomly writing small blocks of data is a much slower. Still, I am pleased with this result. Also in practice the upgrade had a large effect, the laptop feels much more responsive.<br />
<br />
An annoyance with this drive is that it is configured as a slave. When booting the eee, it complains that no master disk is present and demands to press F1. When F1 is pressed, the boot proceeds normally, the unnecessary message just prevents the machine from booting unsupervised.<br />
<br />
I installed <a href="http://www.linuxmint.com/download_lmde.php">Linux Mint Debian Edition</a> on the new drive. I had Ubuntu 11.10 before, which started to show its age. I decided not to upgrade it, after experiencing Ubuntu 12.04 on another machine - I felt that the upgrade to 12.04 broke the user interface. <br />
<br />
I am happy with Linux Mint. However, I came across a couple of problems during the installation. One that looked serious was that GParted reported errors about a recursive partition on the newly installed disk. I could not get rid of this message but decided to continue the installation anyway, and it turned out fine. To reduce the disk writes and the wear, I added <span style="font-family: Courier New, Courier, monospace;">noatime</span> to the mount options for the disk in <span style="font-family: Courier New, Courier, monospace;">/etc/fstab</span>.Anonymoushttp://www.blogger.com/profile/02726645543851535178noreply@blogger.com0tag:blogger.com,1999:blog-7754511132672954918.post-47037848048849653732013-10-17T14:33:00.001+02:002013-10-17T14:33:08.956+02:00Airport luggage cones<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2zGu-sWMib-usq9-SJXveGE49mOxUiOxmh7QOG8xWe7df7e8A40Hvq0z4ACmyjIgqXpKLamyUahontkljy8QBLDALN5Q4Tr2kWk-6pjicnvfWgV5MJzkcWCsArvqcx8AvQMRjjdMT5Vs/s1600/luggagemetalcones.jpg" /><br />
<br />
Found these beauties at the airport. My theory is that they have something to do with luggage transport.Anonymoushttp://www.blogger.com/profile/11894544550052182034noreply@blogger.com0Amsterdam, The Netherlands52.3702157 4.895167899999933152.2151142 4.5724443999999327 52.5253172 5.2178913999999335tag:blogger.com,1999:blog-7754511132672954918.post-26258754660096544722013-09-26T18:12:00.000+02:002013-09-26T18:12:00.166+02:00A more classical anti-ad sign<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8ofWeOmDUltybdidc1euF2T89a1A7cqGJ1yTaGJdlzAgSISLUJBSJ89xFH7EskFZ1sk2v_-QUL4uh3z5RKhiZU-n3HGgCTpK9G36T96zxZzxwRGPmohavp1Js8p28P0U3Py9yf31_1bw/s1600/classic_noads_making.jpg" /><br />
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Making a "no ads please" sign from Hama beads. This time, I'm trying out a more elegant and old-fashioned type design, with muted warms colors. <a href="http://itsacleanmachine.blogspot.com/2013/01/new-hama-anti-ad-sign.html">This is the one I made for our own door.</a><br />
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The text is 20 Reddish Brown and the background is 21 Light Brown. I also put a frame with the "gold" color, not that that really showed in the final stage.<br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixi_ymfKjcrjOUI9jm0qwTY6Z2B6bw3YbOgNRLwwFAmkK1Qw7aTTOLafHAl2oMuf5wJDbvrSxkHUBXZkRlkGgvTzYq7rDpxLG1M9aKriMjhImBSy941lyd6rNFoQJXavTloJPvSqrazgo/s1600/classic_noads_inuse.jpg" /><br />
<br />
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Anonymoushttp://www.blogger.com/profile/11894544550052182034noreply@blogger.com0tag:blogger.com,1999:blog-7754511132672954918.post-31430521103825100852013-09-19T15:00:00.000+02:002013-09-19T15:00:12.093+02:00Beads with Flowing Stripes<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj48sRFZGdjTB8k1HtvYtafp15RJ8y1hZUk5Tx5ojVplOfV5PLGQ0It9pCuhbJ3gWPoaylMeM7hDjSM_TEDtvCfIQH5td46ggEJ-hrhzn7OKaHad2vk6boa07-_renWC2j93GnmSZlHzV8/s1600/done.jpg" /><br />
<br />
Experimenting with striped patterns in polymer clay. I wanted a natural wavy look that would continue across the beads. <br />
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For the base, I used a somewhat translucent dark gray. The gray is mixed from 1 part translucent 'white' (unpigmented) Fimo Soft polymer clay, and 1/32th black Fimo Soft. The stripes are plain white Fimo.<br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhrtYCFYDx6GmOzSDvZiyatPfghcw03253manAKXktFPX4yzDBrMnE4PyFRNigtFSmcwmoizCOuPBRXkEA8kBfDsA_uzcAbjVwVp3GGJ16iuFh3dbZcZDYtcAs6Ah80QkFszSxQBdQz5c0/s1600/mixing.jpg" /><br />
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I made sheets of both colors, rolled on the second-thinnest setting on my pasta machine. A layer of white is sandwiched between two layers of gray. The sheet is then cut into four equally-sized pieces. These four pieces were then stacked, with a bit of scrunching in the middle, to create the wave. The edges are kept neat and unscrunched on purpose. The squares in the background are 1 cm.<br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCS4gl_svB8r83xFk1vL0e7LNYPnz4fo3zxJwCTADm7Fmx-9MveX-M-u_S_X-DlWjlT0zx2fQnr8YOzboD5E-1ErmTKWq4M7L9WxZVmNY8qqvqS8QHx2UKX3fr1jB7AK302VcxLVWld6k/s1600/building.jpg" /><br />
<br />
I made a cylinder of the same gray color as the base, and cut that in half. The wavy stack goes in between the halves. Put together, this approximate cylinder is ready to be reduced! After reducing, I made some of the beads by putting thin slices on a gray base, and some simply by cutting thick slices from the cane (The results were quite similar) <br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVY-J4Ojwn1weidfkkdGwONim_Y11ONCzcOJ51h9URvdy8VSdfLTBYwX7O04dPb_HxjrFgc5-yo8N5uZoWie1UrMEmq_Zzu_jrAOMeHgJ27djdGHQRcAf8gra46Fmrmle_OIeoV8G3HfU/s1600/beads.jpg" /><br />
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Above, the beads before baking, and below, after baking and polishing.Anonymoushttp://www.blogger.com/profile/11894544550052182034noreply@blogger.com1tag:blogger.com,1999:blog-7754511132672954918.post-13208647738380781962013-07-28T23:35:00.000+02:002013-07-28T23:35:22.670+02:00Yashica D resurrection<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjupAjkgnoYSOJd8DnCXNWthQuHwRNlpgzmJvPnxrDW7G06N2kmWKl032ZW0A6O-nadLE0jcuXpgKdDyJzgkw6OgYrfoMb6yghcMZT5GnlMITzRL2uUU_E5cvSx46l-4NyltLOcO-q3CBc/s1600/project.jpg" /><br />
<br />
I found my uncle's old camera when sorting some old things, a <a href="http://camerapedia.wikia.com/wiki/Yashica-D">Yashica D</a>. It has been non-operational for the last 20 years, used mainly for projecting images through the viewfinder onto the ceiling with a flashlight. Now I started wondering if the camera could be used for photography again. The camera looked to be in a nice condition, but the shutter was stuck.<br />
<br />
<a href="http://about.me/mether" target="_blank">Kalle</a> came to the rescue, armed with an excellent guide to <a href="http://ratfactor.com/yashica-d-tlr-copal-mxv-shutter">disassembling the shutter</a> on the Yashica D. We followed the guide, disassembled the shutter mechanism, and found that two shutter blades had stuck. We cleaned the blades and assembled the shutter again, and it worked! <br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQyu5kOalFZ4Xgp017kFY53SkvOcXXPTsZ6gdcdCthRnPs56C-CbFZdoT47ygE9xqszr9UuueQ8x3WLJ3Xw-TAFfoaIJ5Bgxwj-NXRvOTJmAT8xV0wg90j2LJqFYgW6bNNkCJIvF_3AJo/s1600/shutter.jpg" /><br />
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While taking the camera appart, we had to unscrew a lens without damaging or scratching it. A bottle opener turned out to fit the lenses well and gave a suitably gentle but firm grip.<br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEig8Slu2TVwQBzGRwWNR43-NmrGpvvT_5DsPhg6oth73XQfIVMa-EbsXlAH-44kMMoZnt72Sk8eBPfpeGLAkJZO4qL8Wby-u3pgv2v58Are9d6diZu8WR_HV923sMe8r9iTzJ781_hyphenhyphenM9w/s1600/lens.jpg" /><br />
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The shutter is designed in modules, with the self timer and the shutter speed regulator working as independent units. Each one is a kind of clockwork with several cogwheels in series. At one point we opened the wrong screw, and the shutter speed regulator came apart. Putting it back together again was a real challenge, as it contained several small wheels and springs. It was difficult to get all the pieces positioned correctly, so that the top cover could be put back on. What worked for us in the end was clamping a few pieces of cardboard to the desk, and to keep the timer module and its various parts in place with pins stuck into the cardboard.<br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggbRA3O4-ltEqOHKEQ559mMGhYPX0InDRuUDdW7qFyZN9OBIKUr29vlQ9aQJurPY8o54xbVxUWT9SfgMFVZa4fhVqWuj87Ec8YKu6jpemEhwiUNt61PuA9IK3oyNAlM8CuxNYuUFpCGDg/s1600/pins.jpg" /><br />
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I am very impressed by all the small mechanical parts in the shutter, especially considering that it all must have been designed without using computers. It was very pleasing when we got the camera put back together again, and to actually see it work. Kalle has already shot a couple of film rolls with it, here are <a href="http://kmether.ratata.fi/blogg/article-46216-321137-yashica-d-aventyr">a few samples</a>.<br />
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The <a href="http://ratfactor.com/yashica-d-tlr-copal-mxv-shutter">shutter disassembly guide</a> by Dave Gauer was invaluable to us. We also found it useful to take photos of the parts in various stages of disassembly, in order to check the placing and orientation of the parts later when reassembling, and to keep the screws and small parts that came off in each step in a separate bowl.<br />
<br />
Anonymoushttp://www.blogger.com/profile/02726645543851535178noreply@blogger.com0Turku, Finland60.4493248 22.25923160.198594299999996 21.613784 60.7000553 22.904678tag:blogger.com,1999:blog-7754511132672954918.post-86253788612196279962013-04-09T17:42:00.002+02:002013-04-10T14:41:09.951+02:00ISDN adventures<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKIN8lfVLJOWsbtqWuH1vtRQ8J5HPHRcmkII-COpBNPffgypsSm9HovrqE6tBykwPfJgEw6K1Mxy0E4-qj-Ccxc8YInE2zf2OnJjo83ZwHaUO3uc3tWoZt2A9RjYoDpTWXmnIOfL5_FyR-/s1600/draytek_isdn.JPG" /><br />
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I have an ISDN internet connection. It is slow, but happens to be provided for free. Getting ISDN set up under Linux has usually been a challenge for me, so when I got a fresh install working today with very little effort, I wanted to document the steps. Once it starts working, it usually works fine. (Special greetings to everyone in the University guest house in Marburg. Ask for a DrayTek modem and not the Fritz modem, which is a real pain when running Linux. Say you have ein Apple Computer).<br />
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The modem is a DrayTek miniVigor 128 (USB ID 0675:1688), a small box which connects to a USB port on the computer and to a phone for the phone line. The computer runs Ubuntu 11.10 (but I have used the setup on other versions, up to 12.04 without problems).<br />
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There are two ISDN systems in use for Linux. I have used the older one, in particular the HiSax driver supports my ISDN modem. The newer system is called mISDN. The two systems cause a conflict when both try to control the same device. I solved this by blacklisting the mISDN module, to prevent it from being loaded.<br />
<br />
Add a file to <span style="font-family: 'Courier New', Courier, monospace;">/etc/modprobe.d/</span>, for example <span style="font-family: 'Courier New', Courier, monospace;">/etc/modprobe.d/blacklist-misdn.conf</span>, with the following lines:<br />
<span style="font-family: 'Courier New', Courier, monospace;">blacklist mISDN_core</span><br />
<span style="font-family: 'Courier New', Courier, monospace;">blacklist hfcsusb</span><br />
<br />
Install some packages. This is easy if there already is an internet connection...<br />
<span style="font-family: 'Courier New', Courier, monospace;">sudo apt-get install isdnutils-base ipppd</span><br />
<br />
while installing, the installation script for ipppd asks for some information:<br />
<br />
<ul><li>phone number to dial</li>
<li>user name (at your network provider)</li>
<li>password</li>
</ul>The installer script then sets up the following files:<br />
<span style="font-family: 'Courier New', Courier, monospace;">/etc/ppp/pap-secrets #user name, password</span><br />
<span style="font-family: 'Courier New', Courier, monospace;">/etc/ppp/chap-secrets #user name, password</span><br />
<br />
<span style="font-family: 'Courier New', Courier, monospace;">/etc/isdn/device.ippp0 #phone number, etc</span><br />
<span style="font-family: 'Courier New', Courier, monospace;">/etc/isdn/ipppd.ippp0 #user name, channel bundling, etc</span><br />
<br />
At this point I rebooted, after that I could dial with<br />
<span style="font-family: 'Courier New', Courier, monospace;">isdnctrl dial ippp0</span><br />
and had internet access. Not bad. But at this point, the connection uses only one of the two ISDN channels. To double the connection speed to amazing 128 kBit/s, one must set up channel bundling. <br />
<br />
Edit<span style="font-family: 'Courier New', Courier, monospace;"> /etc/isdn/ipppd.ippp0</span>. Uncomment the line #<span style="font-family: 'Courier New', Courier, monospace;">+mp</span>, and add <span style="font-family: 'Courier New', Courier, monospace;">/dev/ippp1</span> above it. So:<br />
<span style="font-family: 'Courier New', Courier, monospace;">/dev/ippp1</span><br />
<span style="font-family: 'Courier New', Courier, monospace;">+mp</span><br />
<br />
Create a new device file for the two bundled devices<br />
<span style="font-family: 'Courier New', Courier, monospace;">sudo cp /etc/isdn/device.ippp0 /etc/isdn/device.ippp0+1</span><br />
<br />
Restart the isdn service after changing the configuration files, to make the new settings active.<br />
<span style="font-family: 'Courier New', Courier, monospace;">sudo /etc/init.d/isdnutils restart</span><br />
<br />
Now, it should be possible to dial first ippp0, then ippp1 and use both channels for fast surfing.<br />
<span style="font-family: 'Courier New', Courier, monospace;">isdnctrl dial ippp0</span><br />
<span style="font-family: 'Courier New', Courier, monospace;">isdnctrl dial ippp1</span><br />
<br />
Note: if you receive the message<br />
<span style="font-family: 'Courier New', Courier, monospace;">ippp0: Device or resource busy</span><br />
it might be because the line is already connected, possibly since the default setting is to automatically dial when there is network traffic.<br />
<br />
If the connection works so far, some adjustments can be done in the configuration files.<br />
<br />
Turn on compression negotiation - perhaps it increases the bandwidth a little.<br />
Comment out the command <span style="font-family: 'Courier New', Courier, monospace;">noccp</span> in <span style="font-family: 'Courier New', Courier, monospace;">/etc/isdn/device.ippp0</span>, remember to copy to the other name as well:<br />
<span style="font-family: 'Courier New', Courier, monospace;">sudo cp /etc/isdn/device.ippp0 /etc/isdn/device.ippp0+1</span><br />
<br />
In <span style="font-family: 'Courier New', Courier, monospace;">/etc/isdn/device.ippp0</span>, adjust timeout for terminating an idle connection. It's only 60 seconds as default. If you are lucky and don't pay per minute, set it to something higher, for example 1800. Change this line:<br />
<span style="font-family: 'Courier New', Courier, monospace;">isdnctrl huptimeout ${device} 60</span><br />
<br />
<span style="font-family: 'Courier New', Courier, monospace;">DIALMODE=manual</span> (instead of <span style="font-family: 'Courier New', Courier, monospace;">auto</span>) disables automatic dialing, and gives you control of when to dial.<br />
<br />
For convenience, one can make two shell scripts for dialing and hanging up:<br />
<span style="font-family: 'Courier New', Courier, monospace;">dial.sh:</span><br />
<span style="font-family: 'Courier New', Courier, monospace;">#!/bin/bash</span><br />
<span style="font-family: 'Courier New', Courier, monospace;">isdnctrl dial ippp0</span><br />
<span style="font-family: 'Courier New', Courier, monospace;">isdnctrl dial ippp1</span><br />
<br />
<span style="font-family: 'Courier New', Courier, monospace;">hangup.sh:</span><br />
<span style="font-family: 'Courier New', Courier, monospace;">#!/bin/bash</span><br />
<span style="font-family: 'Courier New', Courier, monospace;">isdnctrl hangup ippp1</span><br />
<span style="font-family: 'Courier New', Courier, monospace;">isdnctrl hangup ippp0</span><br />
<br />
The configuration file architecture is probably specific to Debian-based distributions, but the step of blacklisting mISDN should help on any Linux with both ISDN systems. I tried to get the ISDN modem working with my <a href="http://itsacleanmachine.blogspot.com/2012/11/raspberry-router.html" target="_blank">Raspberry Pi</a> router as well, but I never got that to work.Anonymoushttp://www.blogger.com/profile/02726645543851535178noreply@blogger.com0tag:blogger.com,1999:blog-7754511132672954918.post-57637288864381452052013-03-31T14:38:00.000+02:002013-03-31T15:24:21.870+02:00Masking & red cabbage dyeing Easter eggs<img alt="Easter eggs dyed with red cabbage" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhozPe8eu8Ex2lpJ8HTIVvyMhUxNjwQop2Eo4Hyl4a4ZddQ0uh08ni5NHkOohZNxWk0pw9BUfkhxXzLfKRk5V6nv077gnbvigyIX64puW-C4J-bNm_DkFwqDTpnGgrbFLIff5FiF4_qvAiL/s1600/done1.jpg" /><br />
<br />
This year we colored Easter eggs with red cabbage juice. The patterns were made by masking the eggs with washi tape and candle wax. <br />
<br />
<img alt="Straining red cabbage" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhiGg340NuB_u1RxGpwX1Y7aNApahVudGC7skbYJtHmIjvcfnvemNUqLOLVURk8NAvL0D0upA8uIWK153PTiVway06omv27e8Sqzc6KNZb_cwdJAf1ek20XmBFsmQKThpnOJjk87CWjmVC2/s1600/cabbage.jpg" /><br />
<br />
To extract the color from red cabbage, I boiled slices of five large leaves in water with some vinegar, for roughly 30 minutes, then removed the cabbage leaves by straining, and allowed the dye to cool. On the right is a piece of cotton string we boiled with the cabbage. It turned a very nice purple, I'm hoping the dye will stick to it. <br />
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<img alt="Covering eggs with washi masking tape" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJQDjHIuiat3-MmkVhEmLN046-_dnsAwCKUaVeiWX6Fm6mUaXSdUcD4lQzgtx6sglPf3FKYWXcyQ83njnEPz9PvH5j3dtSbPTmPEGSYUcuyjta66GhY6CUKGW5caZ-a0oVlYCEjjU9Mzcr/s1600/masking.jpg" /><br />
<br />
To get patterns on the eggs, we covered some parts of them with washi masking tape. We also used molten candle wax, applied with a small paint brush.<br />
<br />
<img alt="Easter eggs soaking in red cabbage dye" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEit0M-rH40WmKhUw4QcUW_hHnBkFWDTd_qcYGnkB-2UD2tokNmHJeFQVjYM9etJ1v2SP_Ep45L8AYo58RJOSGj3WfutJYjMyIOE_u5o2vWkOoJcS0LrqsQYBUuXdsk2o-d43OZPNd-JLpqS/s1600/dye.jpg" /><br />
<br />
The eggs were soaked in the cabbage dye for a few hours. <br />
<br />
<img alt="Dyed Easter eggs" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgLV_Hov3wxU_x7ibQscEVXGpIiZ7UltP7JPOQZUSjuIl5j94ts7dJlnJPFaOXgj353VRf84huiE2xyGX_yPMDOXrwdwV0ukG26WvMxNLYKNROxoSZ0-Q6gaCxJ-YGqBYpwBFTi0-FVqtIs/s1600/dyed.jpg" /><br />
<br />
Rinsing and removing the masking tape. The color is a nice blue, even though the cabbage was red and the dye purple! Red cabbage juice works as a pH indicator; it turns red when acidic and blue in alkaline solutions (and can even turn green or yellow for strong alkalines). It seems there is some chemistry going on in the shells. <br />
<br />
The masking tape worked well - it kept the dye off the masked parts of the egg. Where two stripes of tape crossed each other an unexpected effect appeared: the upper stripe did not mask the egg perfectly just where it passed the lower stripe, giving an illusion of depth in the final pattern! The lines on the egg that appears to pass below another line were created where the tape stripe passed above another stripe.<br />
<br />
The painted-on candle wax gave nice artistic effects!<br />
<br />
<img alt="Dyed Easter eggs" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjI5jAqZPq0Zm607xFWxY5L90S_U2bCW6SEFV-3gPgxduyjW1gfHaUPl8h4_RiT5KZRjR1Jp3Lw5QAMB4-k38q0NXrM1KPjB6RDcLBB-ePJ14UzG7hhdi-ropyKIi0QX3QnohT2XIze_FWS/s1600/done2.jpg" /><br />
<br />
The finished eggs. Happy Easter to everyone!<br />
<br />
Anonymoushttp://www.blogger.com/profile/02726645543851535178noreply@blogger.com2tag:blogger.com,1999:blog-7754511132672954918.post-74538960534952405862013-03-15T20:38:00.004+01:002013-03-15T20:55:16.628+01:00Favourite Games: Widelands<img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqAkgBw_p_Fdsh3b0UbceUHlJkzMlNEyeyB70eiDyTM8i4LRX2Svek87BQzn5oxZmOKrTeE2LLk2636lYip-99QW1-CzxxA6eKK_lVXdemp-4S_i5q8QJMj7lPWybNGKaAu4Yt2usV6tdv/s550/widelands+buildings.png" alt="widelands buildings"/><br />
<a href="http://wl.widelands.org/">Widelands</a> - a strategy game where you build up your civilization and defend it from your enemies. The best defense may well be striking first. Widelands is an open source game, and is said to be similar to Settlers II. The game is still evolving, but is already very enjoyable. <br />
<br />
The game contains a complex economy, with different types of goods and buildings that produce goods or process goods from one form to another. In fact, building and then maintaining a working economy is the main part of the gameplay. There is also fighting with your neighbors, of course, but the battles take place with a minimal input. The only real choice is what to attack, and when to do it.<br />
<br />
<img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzxNmcsQa2fh5ZykGH54s33YNCVRFc_gg5Wq2JtUAH0_R9Y1Z1FZRZLbszS0_NLFypHy-1gdzrsfEkRmtlwELKvZ7765Bh-mC84hm5u6iECyYbog9UC5aoW4EMhyphenhyphenRDlwcNrg46wvzRgIm8/s550/widelands+mines.png" alt="Widelands mines"/><br />
Each warrior needs an axe. Axes are made in an axe factory using iron and coal. Iron is made by combining coal and iron ore in a smelter, these two resources one gets by constructing a mine at a suitable mountain site. However, the miners work only when they are well fed, which requires bread, meat, or fish, prepared into meals in a tavern. Every item produced is transported along roads between the buildings, so having an efficient road network in necessary for a productive economy. When the flow of wares becomes too much for the carriers, one can breed oxen for use as pack animals.<br />
<br />
I like building my empire more than I like fighting the other players, so it suits me fine that the game emphasizes construction over battles. It feels nice to construct an efficient system of factories. In the game I played while writing this post, I ran out of wood in the beginning and then all construction projects ground to a halt. I had a small border battle with my green neighbor, but that war fizzled out when we both ran out of fighters. Then I lost some time before constructing an axe factory, since I believed it required a master blacksmith (which it doesn't). Another thing that caused trouble is that upgrading a building wastes all resources in it. (To save them, one has to order the stores to be emptied before upgrading. This problem is discussed on the bug tracker.) My greedy neighbors left me alone for quite some time even though my defenses were very thin, but eventually they defeated me by burning down my head quarter and storage. I'll get them next time though.<br />
<img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7Lz1OgFJ-9ZhkS6wLWq7X9mgBi2O6aYzLpTpDbOKbWBfpHUiq-QAA05zp25NPwDHTmO8ZQIkoFBbIFjeB5iydSWXFV1szDds8No2b_5_E2WqDPIuDB_lLDMmdgnmhkX-WNbeENV64OiEb/s550/widelands+burning.png" alt="Widelands headquarter destroyed"/><br />
<br />
There is a bit of a learning curve for this game, it takes time to find out how the wares should flow between the different buildings. There is some in-game help, in the form of a tutorial game and a list of all wares and how they are produced. The game music is quite monotonous. Because of it, the game is locally known as the meeh-meeh game. In all other respects, a great game! There is a multiplayer mode which I have not tried, but it sounds like great fun.<br />
<br />
If you feel brave, try out the <a href="http://wl.widelands.org/wiki/DownloadPage/#source_code">development version</a>. The current development version, in preparation of release 18, still has some rough edges, but also notable improvements over the last stable release (17). The graphics is nicer and the colors have improved a lot. They were very saturated before, but are calmer now. <br />
<br />
<br />
<h4>The Favorite Game series<br />
</h4><ul class="cm-list"><li><a href="http://itsacleanmachine.blogspot.com/2012/11/favourite-games-openttd.html">OpenTTD a.k.a. the Train Game</a></li>
<li><a href="http://itsacleanmachine.blogspot.com/2012/12/favourite-games-nethack.html">Nethack</a></li>
<li><a href="http://itsacleanmachine.blogspot.com/2013/03/favourite-games-widelands.html">Widelands</a></li>
</ul>Anonymoushttp://www.blogger.com/profile/02726645543851535178noreply@blogger.com0tag:blogger.com,1999:blog-7754511132672954918.post-34666965069497947962013-03-07T18:35:00.000+01:002013-03-07T18:35:40.177+01:00Red Snail Missing<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDJOgOexdJjBqFA5aPy_mEYVw0BsKKuWY4xR_NzX9qItKrk8vicH-_5LuAD7IxyDFM09ireSfFauDUXcxcBzdw1A4AnkWiSI99YQWz1DfT-UBFRBvYsTNRePX4dH4Li_vFoOe-ma7chks/s1600/redsnailmissing.jpg" /><br />
I recently found a box of my childhood favorite candy, the 'Frog butterfly snail' ones - every eighties kid from Finland knows which ones I mean.<br />
<br />
As a kid, it was always important that the box contained at least one candy of each of the ultimate correct types: red butterfly, yellow snail, and green frog. I'm happy to report success in the present case! In fact, the only combination missing from the box I bought was a red snail.Anonymoushttp://www.blogger.com/profile/11894544550052182034noreply@blogger.com1tag:blogger.com,1999:blog-7754511132672954918.post-81743564070052803072013-03-04T20:59:00.001+01:002013-03-04T20:59:19.775+01:00Fractures and Fractals<script type="text/x-mathjax-config;executed=true">MathJax.Hub.Config({ TeX: { equationNumbers: { autoNumber: "AMS" } }});</script><script src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML" type="text/javascript"></script><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhZ2knMJ0MddtacTJouBV8_ZChFGIuag5MnWIMEciE0-dWduJ5HFYZe1_8XJDVw9N3usvP-rNlD0D0vCbax6ystlD58GoiS66lKc1kqyZACPtGGHiIeLjPgye7Qstpa8nV_MmYVLRugZEHj/s1600/saltfractal.jpg" /><br />
<br />
A wintry day I saw cracks in our parking lot asphalt with salt crystallized around the cracks. The patterns looked nice and reminded me of fractals, and gave a nice topic for a small Processing program. <br />
<br />
Move the mouse over the picture to see different patterns! Click to zoom in, right-click to zoom out.<br />
<br />
<iframe frameborder="0" height="550" scrolling="no" src="http://users.abo.fi/johagron/processing/fractals/index.html" width="550"></iframe><br />
<br />
This is a drawing of the Julia set. Moving the mouse changes the (complex) parameter of the fractal. If you middle-click, you see a picture of the Mandelbrot set. There is an interesting and beautiful connection between the Mandelbrot and Julia sets, which we will get to after a very brief description of how the fractals are drawn. <br />
<br />
Both fractals are drawn by iterating a complex function: \[z_{n+1} = z_n^2 + c.\] Starting with a value \(z_0\), one can use the equation over and over to find a long sequence of \(z\)s. The fractals are images of the complex plane, where each point is colored depending on how the sequence \(z_n\) behaves. Depending on \(c\) and on the staring value \(z_0\), the magnitude of \(z_n\) either stays bounded or explodes when \(n\) grows. If the sequence explodes, the color is chosen according to how many iterations it took for \(|z_n|\) to become larger than some suitable constant. <br />
<br />
For the Mandelbrot fractal one always starts with \(z_0 = 0\), and choose \(c\) according to the point one wants to color. In the Julia fractal, \(z_0\) is the complex coordinate of the point you want to color, while \(c\) is a parameter of the fractal kept fixed for the whole image. Moving the mouse cursor over the image above changes the parameter \(c\).<br />
<br />
The connection between the Julia and Mandelbrot fractals is this: The parameter \(c\) of the Julia fractal corresponds to one point in the image of the Mandelbrot set. When \(c\) is inside the Mandelbrot set (the central area traditionally colored black), the corresponding Julia set is connected. Try different points! It seems that the Julia set keeps the looks (the curlyness and fuzzyness) of the place one chooses in the Mandelbrot set. Points at the edge of the Mandelbrot set tend to be the most interesting.<br />
<br />
While drawing this fractal, I learned that the color map is the key to getting nice pictures. It took some tweaking to get a nice-looking result. Coloring by the logarithm of the iteration count seems to be a good idea. You can have a look at the <a href="http://users.abo.fi/johagron/processing/fractals/fractals_pde.pde">fractal source code</a> here. Finally, one can choose some other complex function to iterate. Simply changing \(z^2\) to \(z^3\) or \(z^4\) gives interesting results.Anonymoushttp://www.blogger.com/profile/02726645543851535178noreply@blogger.com0tag:blogger.com,1999:blog-7754511132672954918.post-52706671978874180342013-02-23T10:50:00.000+01:002013-02-23T10:50:53.240+01:00Mini lanterns on a LED series<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZidMrcQ75nW00S2NI9mMw1e9H1bGB_1n5bqMc6uyhguEPcwLxDNYNDvMUyv8xfurB6sQrM2OcyJfpJYil2e-isJrJsDSqDHDunevXEYnAi74PtRSOgT-RJZ8Nf2KlVu0s2HcTQsbp3yY/s1600/fusenlights2.jpg" /><br />
<br />
I made a set of small paper lanterns for a LED light series we have on a wall (indoors!). The paper lanterns are stylish and easy to make - they are a standard type of origami called 'fusen', which means balloon. I learned about them from the book <a href="http://www.amazon.com/gp/product/1907563083/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1907563083&linkCode=as2&tag=itsacleanmach-20">The Simple Art of Japanese Papercrafts</a> by Mari Ono. These little cubes are inflated after folding, and the air hole was very convenient for putting the fusen on a LED lamp. <br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqT1qZ5j81WP5McA2im4Wp6mPf3sNecPdcCBJm6-NtJFZMv8o2iQhAxg2O39aw6d3kKieWDaRrY2EnRpdfDQLS6wH1pmkSXWKjyolslZEdM2-ZXEBMUEkzWRqWSZcW6iyEB-ZAYM6TxYw/s1600/fusencollection.jpg" /><br />
<br />
The ones I made for this project are quite small. I used 7.5x7.5 cm paper, and the side of the cube is always a quarter of the side of the paper you started with. Since the LEDs don't give off any heat, the small size is not a problem. The origami paper diffuses the light very nicely, and the colors of the papers show up very bright.<br />
<br />
Best of all, the color scheme infinitely adjustable, just by adding and removing colors according to seasons, holidays and moods!<br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiGMNd9WRB4fCn57Oqb5JHfIQPouPin6AZRvbqigO1YnV0xuMcZUxY8ZQKOMysnEbdaNHJqc0ZUq1rFHxfA3mwK-9P3J3wKSaQpoS-U6OkZmFPcXwlnmCt58ruBcpykYsrPp_4VjyvrIn0/s1600/fusenconstruction.jpg" />Anonymoushttp://www.blogger.com/profile/11894544550052182034noreply@blogger.com0tag:blogger.com,1999:blog-7754511132672954918.post-62071868103711676432013-02-19T19:40:00.003+01:002014-06-13T14:34:40.540+02:00WiFi access point with Raspberry Pi<img alt="Raspberry Pi as a WiFi router" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghGRu1TSD7mMCNi18aOWfJ8I6sjcC3ZA07m6eeYrSNqPbSwvenrZf4GYvHS1jXpoA0ZAyas8y-UkP21ulJY2X6XSzgv2uU7O24KIgnaPGhGnseubZidp_8Y_PPlvdoAGRZw9w3G-VDgxIG/s1600/wifirouter.jpg" /><br />
<br />
In a <a href="http://itsacleanmachine.blogspot.com/2012/11/raspberry-router.html">previous post</a>, I talked about using the Raspberry Pi as a router. Now I wanted to add a WiFi device, and use the Pi as an access point as well. The Pi has three network interfaces: <span style="font-family: "Courier New",Courier,monospace;">wlan0</span> is the newly added WLAN device, <span style="font-family: "Courier New",Courier,monospace;">eth0</span> is my LAN, and <span style="font-family: "Courier New",Courier,monospace;">ppp0</span> is a USB GSM modem connecting everything to the internet.<br />
<br />
The primary reason for all of this is to have an access point for an Android phone. It turns out that an ad-hoc network is not enough - Android connects only to real access points (unless rooted and configured to be less suspicious). So the task now is to set up a Linux access point.<br />
<br />
Software-wise, the access point functionality is provided by hostapd, which can be installed on the Pi easily. <br />
<blockquote>
<span style="font-family: "Courier New",Courier,monospace;">sudo apt-get install hostapd</span></blockquote>
The hardware part is quite tricky though - not every wlan card works in access point, or managed, mode in Linux. The state of support in the various drivers can be found at <a href="http://linuxwireless.org/en/users/Drivers/">linuxwireless.org</a>. Among the USB WiFi sticks, ath9k_htc seems well supported. I ended up buying a <a href="http://www.amazon.com/gp/product/B002WBX9C6/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=B002WBX9C6&linkCode=as2&tag=itsacleanmach-20" target="_blank">TL-WN722N</a>, since it is supported by the ath9k_htc drier, and the external antenna looks efficient. It has worked very well so far, and is in daily use. Below, I describe the steps required for setting up everything. I am using Raspbian, but most of the things should work on any distribution.<br />
<br />
<b>The steps</b><br />
Set up a DHCP server. Edit <span style="font-family: "Courier New",Courier,monospace;">/etc/dhcp/dhcpd.conf and add the following lines.</span><br />
<blockquote class="tr_bq">
<span style="font-family: "Courier New",Courier,monospace;">subnet 10.10.0.0 netmask 255.255.255.0 {</span><br />
<span style="font-family: "Courier New",Courier,monospace;">range 10.10.0.25 10.10.0.50;</span><br />
<span style="font-family: "Courier New",Courier,monospace;">option domain-name-servers 8.8.4.4;</span><br />
<span style="font-family: "Courier New",Courier,monospace;">option routers 10.10.0.1;</span><br />
<span style="font-family: "Courier New",Courier,monospace;">interface wlan0;</span><br />
<span style="font-family: "Courier New",Courier,monospace;">}</span></blockquote>
If you already have an entry for DHCP on another subnet on another interface, make sure that the old subnet declaration also specifies for which interface it applies. Next, execute the following commands in a terminal, as root.<br />
<br />
<blockquote class="tr_bq">
<span style="font-family: "Courier New",Courier,monospace;">ifconfig wlan0 10.10.0.1 #bring up the interface </span><br />
<span style="font-family: "Courier New",Courier,monospace;">/etc/init.d/isc-dhcp-server restart #restart the DHCP server</span><br />
<span style="font-family: "Courier New",Courier,monospace;">echo "1" > /proc/sys/net/ipv4/ip_forward #turn on IP forwarding </span><br />
<span style="font-family: "Courier New",Courier,monospace;">iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE #add a routing rule.</span><br />
<br /></blockquote>
Replace<span style="font-family: "Courier New",Courier,monospace;"> ppp0</span> on the last line by the interface connected to the internet. For me <span style="font-family: "Courier New",Courier,monospace;">ppp0</span> is a GSM modem.<br />
<br />
Edit <span style="font-family: "Courier New",Courier,monospace;"> /etc/hostapd/hostapd.conf</span> . Add these lines (as a starting point): <br />
<blockquote class="tr_bq">
<span style="font-family: "Courier New",Courier,monospace;">interface=wlan0</span><br />
<span style="font-family: "Courier New",Courier,monospace;">driver=nl80211</span><br />
<span style="font-family: "Courier New",Courier,monospace;">ssid=YOUR_STATION</span><br />
<span style="font-family: "Courier New",Courier,monospace;">hw_mode=g</span><br />
<span style="font-family: "Courier New",Courier,monospace;">channel=11</span><br />
<span style="font-family: "Courier New",Courier,monospace;">wpa=1</span><br />
<span style="font-family: "Courier New",Courier,monospace;">wpa_passphrase=SECRETPASSWORD</span><br />
<span style="font-family: "Courier New",Courier,monospace;">wpa_key_mgmt=WPA-PSK</span><br />
<span style="font-family: "Courier New",Courier,monospace;">wpa_pairwise=TKIP CCMP</span><br />
<span style="font-family: "Courier New",Courier,monospace;">wpa_ptk_rekey=600</span><br />
<span style="font-family: "Courier New",Courier,monospace;">macaddr_acl=0</span></blockquote>
<br />
Next, start the access point by running hostapd.<br />
<br />
<span style="font-family: "Courier New",Courier,monospace;">hostapd -d /etc/hostapd/hostapd.conf</span><br />
<br />
<span style="font-family: "Courier New",Courier,monospace;">-d</span> is for debugging output.<span style="font-family: "Courier New",Courier,monospace;"> -dd</span> shows even more. Can be useful while setting up.<br />
<br />
Now you should be able to connect to your new access point! Note that when hostapd quits, <span style="font-family: "Courier New",Courier,monospace;">wlan0</span> looses it's IP address. So the IP must be set each time before hostapd is run.<br />
<br />
<img alt="A TP-link TL-WN722N used as an access point" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjpYtTKhoNafdoOrGwUzHbVL5Y3aESCWl5vcelTfBFYj_ZoQXOXaRF30M1KtulaTfwcqeNVSKNBW4XWvIOnB1PWJPGVEdsCI-knDx2Jlf5JlQQHczqDbfbDBVqHt1yZSFz_vH3Df9W6aYTO/s1600/wifiinaction.jpg" /><br />
<br />
If everything works with this setup, it is convenient to automate the startup procedure, so that the access point is enabled at each boot.<br />
<br />
To bring up <span style="font-family: "Courier New",Courier,monospace;">wlan0</span> at boot, add the following to <span style="font-family: "Courier New",Courier,monospace;">/etc/network/interfaces</span><br />
<blockquote>
<span style="font-family: "Courier New",Courier,monospace;">auto wlan0</span><br />
<span style="font-family: "Courier New",Courier,monospace;">iface wlan0 inet static</span><br />
<span style="font-family: "Courier New",Courier,monospace;">address 10.10.0.1</span><br />
<span style="font-family: "Courier New",Courier,monospace;">netmask 255.255.255.0</span></blockquote>
To start hostapd automatically, add the command to <span style="font-family: "Courier New",Courier,monospace;">/etc/rc.local</span>:<br />
<blockquote>
<span style="font-family: "Courier New",Courier,monospace;">hostapd -B /etc/hostapd/hostapd.conf</span></blockquote>
<span style="font-family: "Courier New",Courier,monospace;">-B</span> is for running in the background, as a daemon. Messages are logged in<span style="font-family: "Courier New",Courier,monospace;"><span style="font-family: inherit;"> </span>/var/log/syslog.</span><br />
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For setting up the IP forwarding stuff permanently, see my previous <a href="http://itsacleanmachine.blogspot.de/2012/11/raspberry-router.html">router post</a>, and <a href="http://qcktech.blogspot.de/2012/08/raspberry-pi-as-router.html">this nice guide</a>.<br />
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So far I am very pleased with this setup. The only drawback is that the LAN on <span style="font-family: "Courier New",Courier,monospace;">eth0</span> and the wireless network are separate and isolated from each other. Perhaps it's possible to construct a network bridge between the LAN and the WLAN interface. Then the two networks would appear as one, but this I leave for the next hacking session.<br />
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<b><span style="font-family: "Courier New",Courier,monospace;">Add randomness!</span></b><br />
Finally a note about a puzzling message from hostapd. When run with the flag <span style="font-family: "Courier New",Courier,monospace;">-dd,</span> hostapd works, but outputs<br />
<span style="font-family: "Courier New",Courier,monospace;">Add randomness: count=1 entropy=0</span><br />
<span style="font-family: "Courier New",Courier,monospace;">Add randomness: count=2 entropy=1</span><br />
<span style="font-family: "Courier New",Courier,monospace;">Add randomness: count=3 entropy=2</span><br />
and so on, with a new line every second or so. I thought this had to do with <span style="font-family: "Courier New",Courier,monospace;">/dev/random</span> running out of random bits, but this is not the case. <br />
<br />
Reading the source code of hostapd<span style="font-family: "Courier New",Courier,monospace;"> (version 1.0, since this is what I have on the Pi)</span>, this turns out to be a normal and harmless debugging message. Hostapd keeps an internal pool of random bits (for encryption), in addition to the random numbers it reads from <span style="font-family: "Courier New",Courier,monospace;">/dev/random</span>. In different places in the program, random (or at least unpredictable) data is mixed into this pool. For example the signal strength of each received packet is used in this way. The "<span style="font-family: "Courier New",Courier,monospace;">Add randomness</span>" message is printed each time data is added to the pool. This is done in the function <br />
<blockquote>
<span style="font-family: "Courier New",Courier,monospace;">random_add_randomness (const void *buf, size_t len)</span></blockquote>
in the file <span style="font-family: "Courier New",Courier,monospace;">hostapd-1.0/src/crypto/random.c</span>. So, in summary, the message can safely be ignored, and goes away if one runs hostapd without the <span style="font-family: "Courier New",Courier,monospace;">-dd</span> flag.<br />
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However, on a small system like the Pi, there <i>is</i> a risk of depleting <span style="font-family: "Courier New",Courier,monospace;">/dev/random</span>, especially just after a boot. I observed these messages from hostapd:<br />
<blockquote>
<span style="font-family: "Courier New",Courier,monospace;">random: Got 18/20 bytes from /dev/random</span><br />
<span style="font-family: "Courier New",Courier,monospace;">random: Only 18/20 bytes of strong random data available from /dev/random</span></blockquote>
At this point I installed the program haveged, <br />
<blockquote>
<span style="font-family: "Courier New",Courier,monospace;">sudo apt-get install haveged</span></blockquote>
Haveged is a program that helps with providing randomness or entropy, which it collects faster than the kernel does by default. I have not seen the message since then.Anonymoushttp://www.blogger.com/profile/02726645543851535178noreply@blogger.com21tag:blogger.com,1999:blog-7754511132672954918.post-38874644110972585142013-02-16T19:09:00.000+01:002013-03-07T18:30:59.913+01:00A Pibow case!<img alt="My Raspberry Pi in its new Pibow housing." src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZMalWIVUllIAlckdpFl_J-znUdCgMDK5eK1Y4rHoTzjgwGTAgj3Qtt4FK9Cld04w1r3A1OqG7VlTM6893jw_4fzuihDN79-Ax42mpeK0kCaBpLU2yC42LtzLkoTi_PoFnVoLebpxLgdKE/s1600/pibow.jpg" /><br />
For Christmas I got a <a href="http://shop.pimoroni.com/products/pibow">Pibow</a> case. I like it very much! The Pi in the Pibow case feels nice and robust. The Pi gets slightly warmer in the case than without one, but this has not been a problem at all. Anonymoushttp://www.blogger.com/profile/02726645543851535178noreply@blogger.com0tag:blogger.com,1999:blog-7754511132672954918.post-70599828980512686992013-02-14T16:41:00.000+01:002013-02-14T16:41:50.605+01:00Happy Valentine!<script type="text/x-mathjax-config;executed=true">MathJax.Hub.Config({ TeX: { equationNumbers: { autoNumber: "AMS" } }});</script><script src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML" type="text/javascript"></script><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhYraWOK0WYgjyDq1ZFVw13fnUhjuG1WnBWj7RRxecSfc50tiZEzqTQK6_LONgXjEJWanpYclvfKdq8p7d_f8DygsJYwSKyTQXHPhCSCX4Q1kGxCpl_a57_noOIK0AEYn_1i5k2HlCdWGI/s1600/heartsandtulips_blog.jpg" /><br />
<br />
We wish you all a happy Valentine's day with origami hearts and an equation.<br />
<br />
Let's make a plot in polar coordinates, of \( r = |\phi|^p\). The angle \(\phi\) goes from \(-\pi\) to \(\pi\), and \(p \approx 1 \). Here is the plot, in processing, with \(\phi = 0 \) pointing up. Move the mouse to change \(p\)! <br />
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<a href="http://mathworld.wolfram.com/HeartCurve.html">Mathworld</a> has more equations for hearts, but none of them is as simple as ours. As \(p = 1\) gives a nice shape, \(p\) can be left out for an even simpler equation. <br />
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<iframe frameborder="0" height="550" scrolling="no" src="http://users.abo.fi/johagron/processing/heart/index.html" width="550"></iframe><br />
<br />Anonymoushttp://www.blogger.com/profile/02726645543851535178noreply@blogger.com0tag:blogger.com,1999:blog-7754511132672954918.post-59414090913791476102013-02-10T21:21:00.000+01:002013-02-10T21:51:25.050+01:00Storage system for wrapping paper<img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwIZ3zQD3w1EClHb-gsh2sb6LtWtpK7ePCHEWUK2sn2RqdXbUm7gd9lFe3tUb74nSP0YZ1Cfm-nZXH9zJpxzWN3zRan9K30fkYF-fRdoDqDKDiINV1yD44tN8mFW9EhHfjE3bqFkMY0uM/s1600/stages.jpg" /><br />
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Gift wrapping paper has always been a pain to store. Inspired by several similar arrangements on Pinterest, we made our own gift wrapping organization and storage system, on the inside of a clothes cabinet door. <br />
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For storing rolls of gift-wrapping paper, we used one of the (in Finland) ubiquitous Lanka & Muovi bathroom shelves, which consist of metal wire covered with a softer white plastic. We removed the lower parts of the two upper shelves with a wire cutter. The leftover wire stubs were smoothed down with a Dremel. <br />
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<img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhAbjlBy8rNCudoYjK15621MWXT8dp9iOx5uCVLe1nCI_3CZb9NTjPZbFM5GDxJhCdkSwuzC17lARbRJ2UqEJI_F2-rIXOOrtJfI-jG-RgmLCXBvof2umMBF-Hr_Oevz-ebu90_rfZ3UnA/s1600/paperbasket.jpg" /><br />
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The result was two square ring-like supports over a deeper shelf, good for an almost infinite number of paper rolls!<br />
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Next, we used two Lanka & Muovi bars to make a holder for gift wrapping ribbon rolls. The bars (I really don't know what they're meant for in their original form) needed to be separated from the wall to make space for the ribbon rolls, we did this with some pieces of wood we had lying around. <br />
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<img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhkHQ26shLxIbK829Sr9IgfMch8mpuMbmqOXHCKkSywfmuvRbqx0nZlkbO3hBmDofO0lq8HJdLHE9R0rxXzEBtOJ8lxqWQDZe6qnt0NbIUmezp1uKbQ8IEIdhrTsR0WgbS-GBNUUr1rxKw/s1600/ribbonholder.jpg" /><br />
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We sawed off one end of the metal bars, and put in a hook for that end to rest on. This makes the ribbon rolls re-arrangeable without having to remove the entire thing! <br />
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Another bathroom shelf serves as storage for other gift-wrapping miscellanea: scissors, tape, gift bags, cards, markers...<br />
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<img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjp5aanQMinjRirpInvTqo3SwBIxBL4uMD7FqTo238SSMKXZRPoDMaIriyydOFz-GmF8bDlXtPDdedMwifzXEnTlK_kX1KjWjP_OzFXbZMsbHGij_NRE2h9ROCXPGLD34elQ6t-lX1mjVo/s1600/organizerdone.jpg" /><br />
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Anonymoushttp://www.blogger.com/profile/11894544550052182034noreply@blogger.com2tag:blogger.com,1999:blog-7754511132672954918.post-29964756750378486052013-01-30T20:12:00.001+01:002013-01-30T20:12:18.505+01:00Ice Waves<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZu9C7wXSvCUS8IcgGyzfSMJtR6lWNzUXSN41ImVoH11XielKDFVu024IxqYkylWLMoC_KbOBZX561_ALVaiNHoIlYlXAEIcEEckSwOdvt9jHUyWg0r3e7BNXvnwoMUPgBr8UEthYPp3U/s1600/mushroomice.jpg" /><br />
On a walk in my home town, I came across something which I at first couldn't understand at all - it was water slowly running down an icy rock face, which had created a weird mushroom-like structure.Anonymoushttp://www.blogger.com/profile/11894544550052182034noreply@blogger.com3Turku, Finland60.449249 22.2592389999999860.198521 21.613791999999979 60.699977000000004 22.90468599999998tag:blogger.com,1999:blog-7754511132672954918.post-70062195637071263532013-01-25T23:39:00.000+01:002013-01-25T23:39:38.490+01:00Wintry Moiré<img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAAz2Yx5OpO2-invTUFSeDelgI80MITpB7mFhVVDrr_m7TznF4iaKNkbK0L5hmc6zVd43xDxwZDUFS7KCv0sx3U23KhctinNeNT0mMG1fwJlQkMlW0eDIx8Dv_TMcZkZoBHL74ktjWpVY/s1600/moirecloseup.jpg" /><br />
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<img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOv80tt5ZHHOS3ktS3Wba5qIcr7euILwWW_sMkS6B6FLt-fM-D8wGqlr6W1MHmo2AXyHkgHjy8EdIEXIgNrUEJLX-HY9di6Y2dIPkBE5_-oAdfYLO63bU_6VifubvopUGPDKHjMblOtU0/s1600/moirebox.jpg" /><br />
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I saw an awesome <a href="http://en.wikipedia.org/wiki/Moir%C3%A9_pattern" target="_blank">Moiré</a> pattern, formed from two perforated sheets of metal at slightly different distances from the camera. This gives a slight size difference, and therefore a slight frequency mismatch for the two sheets. It's nice how the original hexagonal pattern of the holes is repeated, hugely, in the Moiré pattern (much nicer than the boring examples on Wikipedia)!Anonymoushttp://www.blogger.com/profile/11894544550052182034noreply@blogger.com0Jyväskylä, Finland62.244747 25.74721840000006536.7227125 -15.561375599999934 87.7667815 67.055812400000065tag:blogger.com,1999:blog-7754511132672954918.post-69409277618183317602013-01-14T23:01:00.000+01:002013-01-15T17:11:26.574+01:00New Hama Anti-Ad Sign<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhqfFKelasF-uCcl-DvUY7d-IzLPxIoj7n0yEz1YDx1Yj87l4yyWHiY2A9xvsA1b8i8DNuk06lHKEK4sHrQrGHAP_EbKefhAWGFz5O3XLh8hHijPJofuGezCQQ7fKCpSv_gu-SzNQOh3dc/s1600/eimainoksia.jpg" />Our previous 'no advertisements' sign proved so popular that it was actually stolen (or anyway, it disappeared, most likely it fell down and was cleaned away or something). So I made a new one.<br />
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The new sign is made with Hama beads, like the old one. The sign has 01 White text on a 17 Grey background. I also made a glow-in-the-dark frame, with 55 Glow-in-the-dark green and 57 Glow-in-the-dark blue. It looks quite nice, a pop of bright color in the dark hallway, but it was very difficult to photograph!<br />
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The text, "Ei mainoksia kiitos!", is Finnish for "No advertisements please".Anonymoushttp://www.blogger.com/profile/11894544550052182034noreply@blogger.com2tag:blogger.com,1999:blog-7754511132672954918.post-74612712359358885752013-01-06T16:54:00.000+01:002013-01-06T19:00:28.154+01:00Nut Domains<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8_GMVXuklPDZHENHwy3f2WzEYg-OoKHlfQPxBt2Z0tV1sjm_iGNjN_qKNg1zZLprImgwr2hbtfmt9KAQq17Q7MB-O8fpuIAvOlHgS3vCCeWalqB342A1JKgDYSxbFmf6IPKsA5sojfsM/s1600/meccano+square+nuts.jpg" /><br />
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The square nuts from our Meccano set. Pushed together randomly, they form nice orientation domains - little areas where each square lines up with its neighbors. Gaps open up between these domains, since they are not lined up with each other.<br />
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The pattern reminds me of a city map, where rectangular buildings on a block are lined up, and then at a bigger street, the angle changes. <br />
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Anonymoushttp://www.blogger.com/profile/11894544550052182034noreply@blogger.com0tag:blogger.com,1999:blog-7754511132672954918.post-718146855371441882013-01-02T22:37:00.000+01:002013-01-02T22:37:02.872+01:00Wiring A Wireless Doorbell<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6Kiqnjcd04CUI_VYMbHLnSyZSNoRSQEmGPPkcxRVC1aRbaqV2k8C4_vEAgPbqCWbzxz9XTpUtCFLK43M1idLGA9QhpUozD7m6TcE0QISrPgtqpIpi9SCzUUVlzklYy6K84yE0jW8odZI/s1600/done.jpg" alt="Wireless doorbell" /><br />
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My father-in-law installed a wireless doorbell. The ring-button outside the door contains a battery and a radio transmitter, the indoor unit contains a radio receiver and a speaker. It turned out that the battery in the ring-button outside does not like the cold Finnish winter, so it went flat. It seems this doorbell is best suited for indoors use...<br />
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We planned to replace the transmitter with an old-fashioned switch with wires, and move the transmitter indoors. Opening up both the receiver and the transmitter first revealed a rather sloppy soldering job, then something about the design of the transmitter and receiver.<br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjp5PiFR4Dq3reKkLnG21XmJ062T_82F0KsP2MbdzwjJVhoRkZPGiUo_ryLlI8QYmjb1VQIxFCEMFXSJChwAbV-xRMJ7_qvS_BpvuJGZkbw4SEzJ8bAPF3J8I2pPpZqHLZJpkgbRcmq_6A/s1600/parts.jpg" alt="Wireless doorbell LP8029" /><br />
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The transmitter contains an encoder chip LP801B, while the receiver contains a LP8029 decoder. The radio circuitry appears to be built with discrete components in both units. The transmitter circuit board has two push-buttons: one for ringing and one for changing the melody. Only the ring-button is accessible when the cover is closed.<br />
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The receiver contains a melody generator chip, under a black plastic blob. Both units have a bank of four dip switches. Pressing the transmitter button causes a noise inside only if the switches in the receiver and transmitter are in identical positions, this is to avoid hearing the doorbells of all neighbors. <br />
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<img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi80ssM4yGoj-4e2EJ8pdMRT3QcFYtZhWwAsvMJUX_RzDwzCjXb18qMK1L5JAXBShNFAA71EDJnF3jpiJdmjLaBeK6Bfj47kevhEcnb4lEIm2h2bJ3daagaA6WXbb6tVLEo0qI5miAjWMA/s1600/wiring.jpg" alt="modified wireless doorbell" /><br />
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The initial plan was to move the transmitter inside, and connect the ring-button outside in parallel with the ring button on the transmitter. After a look at the Japanese <a href="http://aitendo3.sakura.ne.jp/aitendo_data/product_img/wireless/9915B/LP8029L4.pdf">LP8029 data sheet</a>, I found a point in the receiver circuit that starts the ringing noise when momentarily connected to the positive supply. I wired the outdoors button to this point. The transmitter module is now needed only for selecting the melody, the receiver on its own works as an old-fashioned wired doorbell.<br />
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<img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgktfXBElcOaX5djAVGeTGUDsPJXZEXl7z2Id69j4YLahCEXsMAxjQrixw49yLO3KsS75L_etV1ZB1akZl9x1jS5pbpezSgCN1zu2Xl-i93P8Dq1kXYBNnwV_oiB33jTljcAb6M9YDe1kg/s1600/schematic.png" alt="schematic" /><br />
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It was hard to find any information in English about the LP801B and LP8029 chips. An <a href="http://thomaskropf.at/index.php?option=com_content&task=view&id=19&Itemid=28">Austrian hacker</a> found the same encoder chip in the transmitter for radio controlled mains switches. He figured out how to connected the transmitter to a microcontroller, to switch things on and off from a program.<br />
Anonymoushttp://www.blogger.com/profile/02726645543851535178noreply@blogger.com5tag:blogger.com,1999:blog-7754511132672954918.post-81349444791156710002012-12-30T23:35:00.000+01:002012-12-31T10:41:56.030+01:00Five-sided Christmas Star Pastries<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikTC4vhJWHJjuW0jazwkKNwEfrEPokqvc90nNch9BMVyzrYy_5aXtDV9XWXScmOhyphenhyphenOfyUNUnLZaQ1IC4agD4xShYTYVaIUBEPl7eiy9tdTb4d5gcZgxjFS8E2IqdrcZXWx5Ls529_VSUk/s1600/fivesidedchristmasstar.jpg" /><br />
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This is my version of a julstjärna, a <a href="http://sv.wikipedia.org/wiki/Jult%C3%A5rta">traditional scandinavian Christmas pastry</a>, which always has four arms. I wanted to expand the concept a bit. <br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhk3kbp702rA85ldbV_rOf0fB-5ZZZiM-ArFDsvlsw0B1OTQfJA0ekNew6xA2f3z4sGNRMPx1EEHJrDTF-fRgBVw0MQTIQNHmsZPUx-QHCdvn2WwCvXRkYSx1U1Oc21Q0AD9UE2B7n69Wo/s1600/cutting.jpg" /><br />
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Here is how to make it! The traditional four-sided julstjärna is made from a square piece of dough, so our five-sided ones are made from pentagons. A pentagon is of course a much less optimal shape for cutting up the dough sheet, but this is compensated for by the sublime beauty of the finished product!<br />
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Cut from each corner towards the middle, add a blob of plum jam. Fold one corner from each flap over the middle of the pastry. Adding some water to the surface as glue, squeeze until the folded corners stick together.<br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVix6BihjyozHI3GE5AwtKAknJ8D_rILI3E5pItXb9E5PEwvifsRG-j43b3YLP-BJfuhWy1UvRVj3CquvvLZy7VDRflpX4_7dgv4x0YaSsUuxgHbSTzGgWe6-uHRJ2f_02VG6QpPfmcA8/s1600/foldingbaking.jpg" /><br />
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Anonymoushttp://www.blogger.com/profile/11894544550052182034noreply@blogger.com0tag:blogger.com,1999:blog-7754511132672954918.post-22699232312268968452012-12-29T17:36:00.002+01:002013-06-20T17:30:40.465+02:00Color mixes for pastel beads<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVkw-nDJBBf0dV6pWvaYyK7UGG7Rt8XR3UBivnjAQdOAKTlsX9bm-tbeqZmVSwppjIAvOR9Ue-z4jkiHMWKNvvyUbe4HSSTt5GDvvszIp7-iy5LLb6Q0WNBHxl0n1o7i65cpXqNjPKQK4/s1600/pastelbeadsall.jpg" /><br />
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I wanted to make colored translucent beads from <a target="_blank" href="http://www.amazon.com/s/?_encoding=UTF8&camp=1789&creative=390957&field-brandtextbin=Fimo&linkCode=ur2&node=1055398&tag=itsacleanmach-20">Fimo</a> polymer clay. I think the ready-made colored 'translucent' Fimo is too strongly pigmented, and not so translucent. The idea here is to reduce the amount of pigment, by mixing in unpigmented (i. e. 'white') translucent polymer clay.<br />
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Unpigmented clay is very soft, almost too soft to form into beads with any precision. The unpigmented clay in the reddish-violet beads above on the left was a bit dry, which made it much easier to control. But when baking, the dry clay produced a lot more of whitish flakes or stripes you can see in the picture above. I don't mind so much though, it looks a bit like some kind of stone.<br />
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I played around a bit with mixing different colors with varying intensity and lightness, to get the shades I wanted. The glass beads in the picture below served as inspiration and goal, to keep the colors subtle and counteract the temptation to create super-bright shades.<br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibMQvGfYGzjkNXACOwc8lsgnSxPNEdtFRsQA-2TbIFeGEBSW_7DrKqGzGi-j9D4sDG1DmT7hPtLUGgD7J68zMRX8QHxXwEC54NfMJ4M10c20Bh6xFeO6NgfUUtRtBCiZxhOcy_G_BnCdM/s1600/pastelbeadsmisc.jpg" /><br />
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It's impossible to get an accurate idea of the color of these low-pigmented mixes while actually mixing them. Unbaked (in the upper half of picture above) they look almost completely white, since they get translucent only during baking. That's why a color chart comes in handy!<br />
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<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEge1_MQoc-gTjyLn058cLURBCBc16YFKQCTIjgZKvZYONVJ0Upmc9gcD3yfZTMyz2FO5dOZ4o9Dq-t9bZJLlKcUH-axwgTv2FkYeiiyngNeWTLNApxRfvqGBZolOxa6P_MkLGD3JSTlGcc/s1600/specified.jpg" /><br />
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<b>To read the chart:</b> '1 blue + 1 violet + 32 white' means that I mixed 1 part translucent blue, 1 part translucent violet, and 32 parts 'translucent white' (i.e. unpigmented) Fimo polymer clay. In practice, I used one stripe (one eight of a packet) of unpigmented clay, and one 32th of a stripe each of the blue and violet clays. So one part is here just a tiny amount - unless you want to end up with piles of pastel clay.<br />
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The conical turquoise beads are made with a bead roller, the other ones I formed by hand. They were all sanded and polished after baking.<br />
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For the brownish ones, I mixed in a bit of green, as you can see, to get the saturation down. The result it a bit too reddish for my taste. My favorites are the darker turquoise and the bluish violet. Most of these semitransparent pastel colors would probably look nice layered with opaque white!Anonymoushttp://www.blogger.com/profile/11894544550052182034noreply@blogger.com4tag:blogger.com,1999:blog-7754511132672954918.post-84288786212072692622012-12-09T18:11:00.000+01:002012-12-09T21:03:11.954+01:00Iridescent frying pan<img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjz3XJBjIWFC8Mg-YWs_tW3aYk4_U81ilZxokOAwUGeClme4TThPiGVoquUj8TMzgTt_t_znPJDIu6nxaZoGMFet-8BLGxhTdb9YnK92Kn2xyAXHeWvw5Cpsm6YyeoGtGpoPTUkATGQvIW2/s1600/iridescentfryingpan.jpg" /><br />
Our stainless steel frying pan with colorful patterns. Frying stuff in this pan is not particularly nice, since everything, including bacon, seems to stick unless I add lots of fat. The colors offer some consolation, though. I suspect these colors appear due to light <a href="http://en.wikipedia.org/wiki/Thin_film_interference" target="_blank">interference</a> in a thin film of oxide on the pan's surface.<br />
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<a href="http://www.blogger.com/en.wikipedia.org/wiki/File:Wismut_Kristall_und_1cm3_Wuerfel.jpg" target="_blank"><img border="0" width="550px" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEimhdX8h0oLamcfhtNI0LdOmHe_nrqn9Iq_vyPlzgFup-4XIXrTj8fGV5iR6DJD_LNtI7kTMOm42PVPs4nXMQUkiquz6S-M6-93VLqAFKS5LDjEwQbYmQGlkEO3Lg60j5ZuXDeXgzlGRsuY/s1600/640px-Wismut_Kristall_und_1cm3_Wuerfel.jpg" /><br />
This picture of a Bismuth crystal from Wikipedia</a> shows the same effect. The crystal is covered with a thin oxide layer. When light reflected from the top and bottom of the oxide layer interfere, the colors appear. I like the G-shaped growth patterns in this picture even more than the rainbow coloration.Anonymoushttp://www.blogger.com/profile/02726645543851535178noreply@blogger.com0tag:blogger.com,1999:blog-7754511132672954918.post-69291941922307622932012-12-02T19:17:00.002+01:002013-03-15T20:53:54.407+01:00Favorite Games: Nethack<img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQE436X1Kfbz9C8bmI5TKo_lxgOz0Pp8kUMo-ATFNpfK1sdxypPPdz_DvZEd1oeACrW4Kv10z1XrylF_3OLOYYNQGNc6SVedRrBo2BmeZPaTMPCEqtWxXZXiBhSKnXob00orS5lC5AJtQ/s1600/turnintozruty.png" /><br />
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<a href="http://www.nethack.org/">Nethack</a> A classic. You are an @-shaped hero, and your goal is to explore a dungeon filled with monsters (mostly letters) and treasures (gold <span style="background-color: black; color: yellow; font-family: monospace; font-size: 120%;">$</span> and gems <span style="background-color: black; color: red; font-family: monospace; font-size: 120%;">*</span>) and other objects. I haven't played this one seriously for a while - it is much nicer to play on a full keyboard with a number pad, and I seem to usually sit at a laptop. This is a very addictive game, once you get past the initial steep learning curve. For this post we wanted a couple of screenshots, and once we started playing we got hooked again. We even learned to play without the number pad.<br />
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While exploring the dungeon one finds weapons <span style="background-color: black; color: deepskyblue; font-family: monospace; font-size: 120%;">(</span>, armor <span style="background-color: black; color: darkgoldenrod; font-family: monospace; font-size: 120%;">[</span>, and spell books <span style="background-color: black; color: magenta; font-family: monospace; font-size: 120%;">+</span>, and gets tougher by gaining experience and by learning new skills. Nethack is fun because it is so unpredictable. The ascii graphics is very simple, but the world of Nethack is complex. Monsters can interact with each other and with the world around them. You never know what will happen next, and the text description of the events in the dungeon forms an unpredictable story - sometimes a completely absurd fairy tale. <br />
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I grew up playing Nethack on DOS, and liked the way the map is drawn there with full lines for the walls. It is tricky to get this graphic mode to work in a unix terminal, for some reasons connected with different character sets. Anyway, there are several <a href="http://nethack.wikia.com/wiki/IBMgraphicshttp://nethack.wikia.com/wiki/IBMgraphics">solutions</a>. I installed the program konwert, and ran Nethack in this way on one of the text mode consoles (control+alt+f1):<br />
<blockquote>nethack | konwert cp437-utf8</blockquote>Then simply enabling IBMgraphics in the in-game options make the graphics look as it was meant to.<br />
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<img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxz__q0Q8wHSQI9FAeN_aeU5sImFApva4zDmEaArIyLrJkvxHlWoH1xEC-u3rZU-6dz_nH53-qbXyceNUJNcAS0qFYGLmQ4KFFAJc2WFSRdlJjpSROJi7WFPdiB5CsMtR0zIUsO2bO3O0/s1600/nethack-scenes.png" /><br />
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Taking screen shots of a text mode terminal is something I have never needed to do before, but it is possible with the <a href="http://bisqwit.iki.fi/source/snapscreenshot.html">snapscreenshot</a> program. I ran it in this way, in a text-mode console, with Nethack running in console 1:<br />
<blockquote class="tr_bq">sudo snapscreenshot -f8 -c1 -x1 > screenshot1.tga</blockquote>In an X-term window snapscreenshot does not work.<br />
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<h4>The Favorite Game series<br />
</h4><ul class="cm-list"><li><a href="http://itsacleanmachine.blogspot.com/2012/11/favourite-games-openttd.html">OpenTTD a.k.a. the Train Game</a></li>
<li><a href="http://itsacleanmachine.blogspot.com/2012/12/favourite-games-nethack.html">Nethack</a></li>
<li><a href="http://itsacleanmachine.blogspot.com/2013/03/favourite-games-widelands.html">Widelands</a></li>
</ul>Anonymoushttp://www.blogger.com/profile/02726645543851535178noreply@blogger.com0