Reverse-Engineering A Shahed-136 Drone Air Data Computer

July 15, 2024 by 22 Comments
Top of the air data computer module, with pressure sensors, RS232 driver and DC-DC converter visible. (Credit: Le Labo de Michel, YouTube)

An air data computer (ADC) is a crucial part of an avionics package that can calculate the altitude, vertical speed, air speed and more from pressure (via pitot tubes) and temperature inputs. When your airplane is a one-way attack drone like Iran’s Shahed-136, you obviously need an ADC as well, but have to focus on making it both cheap and circumvent a myriad of sanctions. As [Michel] recently found out while reverse-engineering one of these ADCs. Courtesy of the Russo-Ukrainian war, hundreds of these Shahed drones are being destroyed every month, with some making it back down again intact enough for some parts to end up on EBay.

The overall design as captured in the schematic is rather straightforward, with the component choice probably being the most notable, as it uses an STM32G071 MCU and Analog Devices ADM3232 RS-232 driver, in addition to the two pressure sensors (by Silicon Microstructures Inc., now owned by TE). The DC-DC converter is a Mornsun URB24055-6WR3.

With the board in working condition, [Michel] hooks it up to a test setup to see the output on the serial interface when applying different pressures to the pressure sensor inputs. This results in a lot of ASCII data being output, all containing different values that were calculated by the firmware on the STM32 MCU. In the drone this data would then be used by the flight computer to make adjustments. Overall it’s a rather basic design that doesn’t seem to have a dedicated temperature sensor either, though [Michel] is still analyzing some details. A firmware dump would of course be rather fascinating as well.

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A Solar-Powered Wristwatch With An ATtiny13

March 13, 2024 by 22 Comments

Wristwatches come in many shapes, sizes, and types, but most still have at least one thing in common: they feature a battery that needs to be swapped or recharged somewhere been every other day and every few years. A rare few integrate a solar panel that keeps the internal battery at least somewhat topped up, as environmental light permits.

This “Perpetual” wristwatch designed by [Serhii Trush] aims to keep digitally ticking along using nothing but the integrated photodiodes, a rechargeable LIR2430 cell, and a power-sipping face that uses one LED for each hour of the day.

The face of the perpetual wristwatch. (Credit: Serhii Trush)
The face of the perpetual wristwatch. (Credit: Serhii Trush)

The wristwatch’s operation is demonstrated in the linked video (in Ukrainian, auto-generated subtitles available): to read out the current time, the button in the center is pressed, which first shows the hour, then the minutes (in 5 minute intervals).

After this the ATtiny13 MCU goes back to sleep, briefly waking up every 0.5 seconds to update the time, which explains why there’s no RTC crystal. The 12 BPW34S photodiodes are enough to provide 2 mA at 0.5 V in full sunlight, which together keep the LIR2430 cell charged via a Zener diode.

As far as minimalistic yet practical designs go, this one is pretty hard to beat. If you wish to make your own, all of the design files and firmware are provided on the GitHub page.

Although we certainly do like the exposed components, it would be interesting to see this technique paired with the PCB watch face we covered recently.

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Gentoo Linux, Now A Bit Less For The 1337

December 29, 2023 by 37 Comments

Among users of Linux distributions there’s a curious one-upmanship, depending on how esoteric or hardcore  your distro is. Ubuntu users have little shame, while at the other end if you followed Linux From Scratch or better still hand-compiled the code and carved it onto the raw silicon with a tiny chisel, you’re at the top of the tree*. Jokes aside though, it’s fair to say that if you were running the Gentoo distribution you were something of a hardcore user, because its source-only nature meant that everything had to be compiled to your liking. We’re using the past tense here though, because in a surprise announcement, the distro has revealed that it will henceforth also be available as a set of precompiled binary packages.

There may be readers with long and flowing neckbeards who will decry this moment as the Beginning of the End, but while it does signal a major departure for the distro if it means that more people are spurred to take their Linux usage further and experiment with Gentoo, this can never be a bad thing. Gentoo has been on the list for a future Jenny’s Daily Drivers OS review piece, and while we’re probably going to stick with source-only when we do it, it’s undeniable that there will remain a temptation to simply download the binaries.

Meanwhile this has been written on a machine running Manjaro, or Arch-for-cowards as we like to call it, something that maybe confers middle-ranking bragging rights. Read a personal tale of taking off those Linux training wheels.

* Used a magnifying glass? You’re just not cutting it!

Tektronix’s Ceramic CRT Production And The Building 13 Catacombs

November 27, 2023 by 17 Comments

As a manufacturer of test equipment and more, Tektronix has long had a need for custom form factors with its CRT displays. They initially went with fully glass CRTs as this was what the booming television industry was also using, but as demand for the glass component of CRTs increased, so did the delays in getting these custom glass components made. This is where Tektronix decided to use its existing expertise with ceramic strips during the pre-PCB era to create ceramic funnels for ceramic CRTs, as described in this 1967 video.

The Tektronix ceramic CRT molds underneath Building 13.
The Tektronix ceramic CRT molds underneath Building 13.

Recently, underneath Building 13 at the Tektronix campus, a ‘catacomb’ full of the molds for these funnels was discovered, covering a wide range of CRT types, including some round ones that were presumably made for military purposes, such as radar installations. These molds consist out of an inner part  (the mandrel) made from 7075-T6 aluminium, and an outer cast polyurethane boot. The ceramic (forsterite) powder is then formed under high pressure into the ceramic funnel, which is then fired in a kiln before a full inspection and assembly into a full CRT, including the phosphor-coated glass front section and rear section with the electron guns.

The advantages of ceramic funnels over glass ones are many, including the former being much harder and resilient to impact forces, while offering a lot of strength for thinner, lighter structures, all of which is desirable in (portable) lab equipment. Although LCDs would inevitably take over from CRTs here as well, these ceramic CRTs formed an integral part of Tektronix’s products, with every part of production handled in-house.

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Life Imitates ART (ART-13, That Is)

November 23, 2023 by 4 Comments

[Mr. Carlson] has been restoring vintage military radios, and as part of his quest, he received an ART-13 transmitter. Before he opened the shipping box, he turned on the camera, and we get to watch from the very start in the video below. These transmitters were originally made by Collins for the Navy with an Army Air Corps variant made by Stewart-Warner. Even the Russians made a copy, presumably by studying salvaged units from crashed B-29s.

The transmitter puts out 100 watts at frequencies up to 18.1 MHz. The tubes needed a plate supply, and so, like many radios of the era, this one used a dynamotor. Think of it as a motor running at one voltage and turning a generator that produces a (usually) higher voltage. If you ever used a radio with one, you know you didn’t need an “on the air” sign — the whine of the thing spinning would let everyone know you had the key or microphone button pushed down. It’s an interesting piece of bygone tech that we’ve looked into previously.

The transmitter wasn’t in perfect shape, but we’ve seen worse. When the lid comes off, you can practically smell the old radio odor. There are tubes, coils, and even a vacuum relay, presumably for transmit/receive switching of the antenna. [Carlson] also tears open the dynamotor which is something you don’t see every day.

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$13 Scope And Logic Analyzer Hits 18 Msps

September 26, 2023 by 31 Comments

We aren’t sure what’s coolest about [Richard Testardi’s] Flea-Scope. It costs about $13 plus the cost of making the PCB. It operates at 18 million samples per second. It also doesn’t need any software — you connect to it with your browser! It works as an oscilloscope, a logic analyzer, and a waveform generator. Not bad. The board is basically a little life support around a PIC32MK and the software required to run it.

Of course, for $13, you need to temper your expectations. One analog input reads from -6 to 6V (hint: use a 10X probe). The goal was for the instrument to be accurate within 2%.  There are also nine digital inputs sampled simultaneously with the analog sampling. The signal generator portion can output a 4 MHz square wave or a 40 kHz arbitrary waveform.

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Hackaday Links: August 13, 2023

August 13, 2023 by 14 Comments

Remember that time when the entire physics community dropped what it was doing to replicate the extraordinary claim that a room-temperature semiconductor had been discovered? We sure do, and if it seems like it was just yesterday, it’s probably because it pretty much was. The news of LK-99, a copper-modified lead apatite compound, hit at the end of July; now, barely three weeks later, comes news that not only is LK-99 not a superconductor, but that its resistivity at room temperature is about a billion times higher than copper. For anyone who rode the “cold fusion” hype train back in the late 1980s, LK-99 had a bit of code smell on it from the start. We figured we’d sit back and let science do what science does, and sure enough, the extraordinary claim seems not to be able to muster the kind of extraordinary evidence it needs to support it — with the significant caveat that a lot of the debunking papers –and indeed the original paper on LK-99 — seem still to be just preprints, and have not been peer-reviewed yet.

So what does all this mean? Sadly, probably not much. Despite the overwrought popular media coverage, a true room-temperature and pressure superconductor was probably not going to save the world, at least not right away. The indispensable Asianometry channel on YouTube did a great video on this. As always, his focus is on the semiconductor industry, so his analysis has to be viewed through that lens. He argues that room-temperature superconductors wouldn’t make much difference in semiconductors because the place where they’d most likely be employed, the interconnects on chips, will still have inductance and capacitance even if their resistance is zero. That doesn’t mean room-temperature superconductors wouldn’t be a great thing to have, of course; seems like they’d be revolutionary for power transmission if nothing else. But not so much for semiconductors, and certainly not today.

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