stm32

216 Articles

Teardown: Impassa SCW9057G-433 Alarm System

September 9, 2021 by 15 Comments

This series of monthly teardowns was started in early 2018 as an experiment, and since you fine folks keep reading them, I keep making them. But in truth, finding a new and interesting gadget every month can sometimes be a chore. Which is why I’m always so thankful when a reader actually sends something in that they’d like to see taken apart, as it absolves me from having to make the decision myself. Of course it also means I can’t be blamed if you don’t like it, so keep that in mind as well.

Coming our way from the tropical paradise of Eastern Pennsylvania, this month’s subject is an ADT branded Impassa SCW9057G-433 alarm system that was apparently pulled off the wall when our kind patron was moving house. As you might have guessed from the model number, this unit uses 433 MHz to communicate with various sensors and devices throughout the home, and also includes a 3G cellular connection that allows it to contact the alarm monitoring service even if the phone line has been cut.

Diagram of Impassa home security setup
The alarm can connect to a wide array of 433 MHz devices.

From how many of these are on eBay, and the research I’ve done on some home alarm system forums, it appears that you can actually pick one of these up on the second-hand market and spin your own whole-house alarm system without going through a monitoring company like ADT. The extensive documentation from Impassa covers how to wire and configure the device, and as long as the system isn’t locked when you get it, it seems like wiping the configuration and starting from scratch isn’t a problem.

If it’s possible to put together your own homebrew alarm system with one of these units at the core, then it seems the least we can do is take it apart and see what kind of potentially modifiable goodies are waiting under that shiny plastic exterior.

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Incredibly Slow Films, Now Playing In Dazzling Color

August 12, 2021 by 8 Comments

Back in 2018 we covered a project that would break a video down into its individual frames and slowly cycle through them on an e-paper screen. With a new image pushed out every three minutes or so, it would take thousands of hours to “watch” a feature length film. Of course, that was never the point. The idea was to turn your favorite movie into an artistic conversation piece; a constantly evolving portrait you could hang on the wall.

[Manuel Tosone] was recently inspired to build his own version of this concept, and now thanks to several years of e-paper development, he was even able to do it in color. Ever the perfectionist, he decided to drive the seven-color 5.65 inch Waveshare panel with a custom STM32 board that he estimates can wring nearly 300 days of runtime out of six standard AA batteries, and wrap everything up in a very professional looking 3D printed enclosure. The end result is a one-of-a-kind Video Frame that any hacker would be proud to display on their mantle.

The Hackaday.IO page for this project contains a meticulously curated collection of information, covering everything from the ffmpeg commands used to process the video file into a directory full of cropped and enhanced images, to flash memory lifetime estimates and energy consumption analyses. If you’ve ever considered setting up an e-paper display that needs to run for long stretches of time, regardless of what’s actually being shown on the screen, there’s an excellent chance that you’ll find some useful nuggets in the fantastic documentation [Manuel] has provided.

We always love to hear about people being inspired by a project they saw on Hackaday, especially when we get to bring things full circle and feature their own take on the idea. Who knows, perhaps the next version of the e-paper video frame to grace these pages will be your own.

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Tamagotchis Everywhere

August 10, 2021 by 13 Comments

Tamagotchi’s relatively simple technical complexity pales in comparison to its huge cultural impact, with over 76 million sold. It has spawned comics, stories, numerous toys, and offshoots such as an anime and two films. [JC] was looking through some of his old stuff and came across a Tamagotchi P1 (the original Tamagotchi) and decided to create a portable emulator for it. The ROM for the P1 has long been dumped and can be run within a MAME emulator. After all, it’s just a 32MHZ E0C6S46 Epson MCU, 32×16 LCD with 8 additional icons, three buttons, and a piezo. The manual for the MCU is even available on Epson’s website. Here at Hackaday, we’ve seen Tamagotchis many times before, such as the infinite matrix of the Tamagotchi Singularity and a ROM dump of the latest generation of Tamagotchi based on a 6502 core.

So what’s different about what [JC] is trying to accomplish? For starters, the tooling. It is divided into two parts: TamaLIB and TamaTool. The first is a hardware-agnostic P1 emulation library that relies on a HAL layer to communicate with the hardware. The second is a frontend for the first, allowing debugging, RAM editing, and modifications to the ROM. In particular, it supports easy modification of images within the ROM and allows for custom eggs and Tamagotchis. The homage to the Jolly Wrencher is nice.

Given that the emulation is platform-agnostic and access to a low-resolution timer is not guaranteed, cycle counts become tricky. The rather clever solution [JC] stumbled upon was synchronizing against input polling, screen updates, and sound output. TamaLIb keeps track of how many CPU cycles have passed and regularly checks if the emulation is going too fast or too slow. Slowing down or speeding up the simulation allows it to seem to run in real-time.

The last goal [JC] had was to run it on embedded hardware. Using an STM32F072 board and a cheap OLED screen had a portable emulated Tamagotchi known as MCUGotchi. The code is available on GitHub and should work on most STM32 MCUs with a few small tweaks. Now that someone has gone through the effort to make it easy to run a Tamagotchi literally anywhere, it might not be long until we see a coffee maker or a smart light acting as a Tamagotchi. Perhaps the new joke will be, can it run Tamagotchi?

Video after the break.

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Wooden Linear Clock Aided By GPS

July 5, 2021 by 23 Comments

The notion of segmenting and quantizing the day into discrete segments of time is perhaps one of the most human things we do. Heralding back to a simpler era when a day was just a progression of sunrise to sunset, [James Wilson] created a beautiful linear clock that shows time as progress throughout the day.

For previous projects, [James] had used nixie tubes but the headache of the inverters, high voltages, and tight spaces led him to instead use mini-LED’s. Two PCBs were manufactured, one as the display and one to hold the GNSS module as it works best when mounted horizontally to point at the sky. Two rows of 112 tightly packed LEDs make a great stand-in for bar graph style tubes and are are controlled by TLC5926 shift registers. The venerable STM32G0 was chosen as the microcontroller to power the clock. With the help of some approximating functions and the location provided by the GNSS module [James] had the position of the sun which he then could turn into a % of progress through the sky.

The enclosure was modeled after the mid-century modern look and made of several pieces of wood CNC’d and then glued together. Machining it out of a solid piece of wood would have been difficult as finding long enough end mills that could carve out the interior is tricky. We think the resulting clock looks wonderful and the walnut accents the maple nicely.

The writeup is highly detailed and we love the honest explanations of what choices were made and why. The code is available on GitHub. Or if perhaps you’d rather eschew the LED’s and go for something more physical there’s always this ratcheting linear clock to draw inspiration from.

Test Your ‘Blue Pill’ Board For A Genuine STM32F103C8 MCU

June 23, 2021 by 38 Comments

With the market for STM32F103C8-based ‘Blue Pill’ boards slowly being overrun with boards that contain either a cloned, fake or outright broken chip, [Terry Porter] really wanted to have an easy, automated way to quickly detect whether a new board contains genuine STM32 silicon, or some fake that tries to look the part. After more than a year of work, the Blue Pill Diagnostics project is now ready for prime time.

We have covered those clone MCUs previously. It’s clear that some of those ‘Blue Pill’ boards obviously do not have a genuine STM32 MCU on them, as they do not have the STM32 markings on them, while others fake those markings on the package and identifying can be hard to impossible. Often only testing the MCU’s actual functionality can give clarity on whether it’s a real STM32 MCU.

These diagnostics allow one to test not only the 64 kB of Flash, but also the 64 kB of ‘hidden’ Flash that’s often found on these MCUs (rebadged 128 kB STM32F103 cores). It further checks the manufacturer JDEC code and uses a silicon bug in genuine STM32F1xx MCUs where the BGMCU_IDCODE cannot be read without either SWD or JTAG connected.

Another interesting feature of Blue Pill Diagnostics is using Mecrisp-Stellaris Forth as its foundation, which allows for easy access to a Forth shell via this firmware as well, not unlike MicroPython and Lua, only in a fraction of the Flash required by those. We have previously written about using Mecrisp-Stellaris in your projects.

Mickey’s Big Timer Makes Glider Competitions Better

June 13, 2021 by 2 Comments

There’s plenty of obscure sports in the world. Many of them could benefit from bespoke equipment like scoring displays, but are too obscure to support commercial efforts in this regard. Radio controlled glider competitions fit into just this category. This led a man named [Mickey] to develop what he calls Mickey’s Big Timer, to aid in the running of such events.

Glider events run outdoors in full sunlight, so the system uses big bright LED matrix displays to show its timing information. The system, built around the STM32 Discovery platform, uses several of the microcontroller boards to drive several displays as well as the main controller which handles timing. It also packs in an audio system for issuing instructions to competitors. It can also display pilot names as well as instructions such as when competitors should land at the end of a heat.

Some code is available on Github for those interested in how it all works. Word around the RC forums has it that [Mickey] built several systems, some of which ended up as far afield as New Zealand where they helped run many successful glider contests over the years.

We’ve seen plenty of scoreboard projects over the years; a little portable one could be useful for adding some spice to your pickup neighbourhood games. Video after the break.

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Portable, Digital Scoreboard Goes Anywhere

June 7, 2021 by 22 Comments

It’s that time of year in both hemispheres — time to get outside and play before it gets unbearably hot (or cold). No matter what your game, don’t keep score in your head or with piles of rocks — make yourself a portable, fold-able scoreboard like [LordGuilly] did and be on the bleeding edge of display technology. It’s really more roll-able than fold-able, which is awesome because you get to unfurl it like a boss.

All you need is a place to hang it up and you’re good to go. This thing runs on a beefy 10,000 mAH USB power bank, and [LordGuilly] says that it’s easy to read even on really sunny days. As you may have guessed, those are WS2812 strips and they are set into rectangular PVC bars. The bars are set equidistant from each other in a frame made from modified version of cable tracks — plastic chain links for cable management.

Good looks aside, we especially like that there are two controller options here. If you want to assign a dedicated scorekeeper, there’s a handled version that uses an STM32 blue pill and is wired to the display. But if you’re short on people, use the ESP8266 version and update the score with the accompanying app. Check out the demo after the break so you can see it in action.

We’ve seen a few scoreboards over the years, including this beauty that’s meant for indoor games.

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