Reverse Engineering on Sarah's Microbloghttp://salr.cc/tags/reverse-engineering/Recent content in Reverse Engineering on Sarah's MicroblogHugoen-usWed, 26 Aug 2026 23:00:02 +0200Got absolutely sniped todayhttp://salr.cc/tmp/post/tech/post/1787769902/Wed, 26 Aug 2026 23:00:02 +0200http://salr.cc/tmp/post/tech/post/1787769902/<p>I was asked <em>so how does this thing work?</em><br> <figure> <a href="http://salr.cc/tmp/post/tech/post/1787769902/papanek-tin-can-radio_hu_92efe24de91a5a3e.jpg" target="_blank"> <img src="http://salr.cc/tmp/post/tech/post/1787769902/papanek-tin-can-radio_hu_d52da476cd7bd118.webp" alt="The Tin Can Radio by Papanek and Seeger"> </a> </figure></p> <p>From <a href="https://papanek.org">papanek.org</a> via <a href="https://www.smjny.com/ex20240209williamcordovaradioreceiver">smjny.com</a></p> <p>This is the &lsquo;Tin Can Radio&rsquo; by Victor Papanek and George Seeger. There appears to exist exactly three images of this thing online. It&rsquo;s a radio reciever from 1962 intended for &rsquo;third world&rsquo; countries. From texts referencing it, it&rsquo;s generally explained that the radio is not selective (it can not be tuned), that it is somehow powered by burning candle wax or cow dung in the tin can, it features a transitor (?), a 9 cent bill of materials and is possible to assemble by hand.</p><link>http://salr.cc/tmp/post/tech/post/1787418190/</link><pubDate>Sat, 22 Aug 2026 19:03:10 +0200</pubDate><guid>http://salr.cc/tmp/post/tech/post/1787418190/</guid><description><figure> <a href="http://salr.cc/tmp/post/tech/post/1787418190/FrekvensOriginal.svg" target="_blank"> <img src="http://salr.cc/tmp/post/tech/post/1787418190/FrekvensOriginal.svg" alt="Full reverse engineered schematic of the Frekvens boards"> </a> </figure><p>Complete RE of the original Frekvens controller and LED matrix board.</p></description></item><item><title/><link>http://salr.cc/tmp/post/tech/post/1787155297/</link><pubDate>Wed, 19 Aug 2026 18:01:38 +0200</pubDate><guid>http://salr.cc/tmp/post/tech/post/1787155297/</guid><description><figure> <a href="http://salr.cc/tmp/post/tech/post/1787155297/PXL_20260819_160339872~2_hu_77f250a3fd0d49a0.jpg" target="_blank"> <img src="http://salr.cc/tmp/post/tech/post/1787155297/PXL_20260819_160339872~2_hu_a8a071cd74f37520.webp" alt="The MCU on the controller board, reading 89F112 000"> </a> </figure><p>The MCU on the controllerboard has the markings <code>89F112 000</code>, which appears to be the CMS89F112 from Cmsemicon. It&rsquo;s listed <a href="https://jlcpcb.com/partdetail/Cmsemicon-CMS89F112/C497640">on jlc</a>, for an estimated unit price of 0.3 USD. Hard to beat. The <a href="C497640.pdf">datasheet</a> is in chineese, but looks to have</p> <ul> <li>A 2K x 14 bit flash memory (I&rsquo;m unfamiliar with the practicality of 14 bit memory?).</li> <li>144 bytes of RAM.</li> <li>Inbuilt ADC, comparators, timers, PWM outputs, buzzer driver and a sleep mode.</li> <li>A voltage range of 1.8-5.5V (at 4MHz, or from 2.5V at 8MHz).</li> </ul> <p>A very capable little device. 144 bytes of RAM is not a lot, a bitfield for the LED matrix would take up 32 bytes, almost a quarter of memory. Still, that is absolutely enough for more complex or interesting effects on the matrix, like iterative or dynamic animations. My claim still stands: TE&rsquo;s embedded developers dropped the ball on this one.</p></description></item><item><title/><link>http://salr.cc/tmp/post/tech/post/1787089778/</link><pubDate>Tue, 18 Aug 2026 23:49:39 +0200</pubDate><guid>http://salr.cc/tmp/post/tech/post/1787089778/</guid><description><p>Scans and sketch of the original circuit:</p> <span class="gallery"> <figure> <a href="http://salr.cc/tmp/post/tech/post/1787089778/pcb1-f-crop_hu_de739a219b40f04b.jpg" target="_blank"> <img src="http://salr.cc/tmp/post/tech/post/1787089778/pcb1-f-crop_hu_9ebfa21f2a6eb91d.webp" alt="Controller PCB Front"> </a> </figure> <figure> <a href="http://salr.cc/tmp/post/tech/post/1787089778/pcb1-b-crop_hu_fe9a24fa881f234.jpg" target="_blank"> <img src="http://salr.cc/tmp/post/tech/post/1787089778/pcb1-b-crop_hu_603f043d5431f2fa.webp" alt="Controller PCB Back"> </a> </figure></span> <span class="gallery"> <figure> <a href="http://salr.cc/tmp/post/tech/post/1787089778/pcb2-f-crop_hu_7c861daca80b15b7.jpg" target="_blank"> <img src="http://salr.cc/tmp/post/tech/post/1787089778/pcb2-f-crop_hu_d2bc6df4b78b1247.webp" alt="LED Matrix PCB Front"> </a> </figure> <figure> <a href="http://salr.cc/tmp/post/tech/post/1787089778/pcb2-b-crop_hu_9a6f9c83e15b2a26.jpg" target="_blank"> <img src="http://salr.cc/tmp/post/tech/post/1787089778/pcb2-b-crop_hu_56fe4130aeb64160.webp" alt="LED Matrix PCB Back"> </a> </figure></span> <span class="gallery"> <figure> <a href="http://salr.cc/tmp/post/tech/post/1787089778/IMG_0017-crop_hu_ccdeda012b8bb3b8.jpg" target="_blank"> <img src="http://salr.cc/tmp/post/tech/post/1787089778/IMG_0017-crop_hu_540604832d5213e0.webp" alt="Sketch of the original frekvens circuitry part 1."> </a> </figure> <figure> <a href="http://salr.cc/tmp/post/tech/post/1787089778/IMG_0019-crop_hu_2559b7fe2b369cf6.jpg" target="_blank"> <img src="http://salr.cc/tmp/post/tech/post/1787089778/IMG_0019-crop_hu_70581ca3e9a00a02.webp" alt="Sketch of the original frekvens circuitry part 2."> </a> </figure></span> <p>Cleaner sketch to follow&hellip;</p></description></item></channel></rss>