Play Tetris on a Transistor Tester, Because Why Not?

[Robson] had been using the same multimeter since he was 15. It wasn’t a typical multimeter, either. He had programmed it to also play the Google Chrome jumping dinosaur game, and also used it as a badge at various conferences. But with all that abuse, the ribbon cable broke and he set about on other projects. Like this transistor tester that was just asking to have Tetris programmed onto its tiny screen.

The transistor tester is a GM328A made for various transistor testing applications, but is also an LCR meter. [Robson]’s old meter didn’t even test for capacitance but he was able to get many years of use out of that one, so this device should serve him even better. Once it was delivered he set about adding more features, namely Tetris. It’s based on an ATmega chip, which quite easy to work with (it’s the same chip as you’ll find in the Arduino Uno but [Robson’s] gone the Makefile route instead of spinning up that IDE). Not only did he add more features, but he also found a mistake in the frequency counter circuitry that he fixed on his own through the course of the project.

If you’ve always thought that the lack of games on your multimeter was a total deal breaker, this project is worth a read. Even if you just have a random device lying around that happens to be based on an ATmega chip of some sort, this is a good primer of getting that device to do other things as well. This situation is a fairly common one to be in, too.

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Low Power Weather Station Blows the Competition Away

Building a weather station isn’t too tall of an order for anyone getting into an electronics project. There are plenty of plans online, and you can even put your station on Weather Underground if it meets certain standards. These usually have access to a reliable source of power, though, and like any electronics project can get challenging quickly once it needs to work reliably in a remote location. The weather station from [Tegwyn☠Twmffat] has met this challenge though, and has been working reliably for three years now.

Getting that sort of reliability from any circuit that has to be powered by an unreliable source (solar, wind, etc.) and a battery is quite a challenge. Not only do you need to sort out the power management and make sure that you can get enough sun in the winter for your application, but you’ll need to do some extreme low power modifications to your circuitry as well. This weather station accomplishes all of that, helped by using LoRa for communication, and also comes complete with a separate hardware watchdog timer that can reboot the weather station if it loses power or hangs up for some reason.

If you’ve been looking for a weather station to build, this is a great place to start. [Tegwyn☠Twmffat] also goes through the assembly of the weather station, complete with a guy-wire-supported platform to mount it on. There are other weather stations out there too, if you need even more ideas about saving power in remote areas.

FemtoBeacon Is A Tiny ESP32 Coin-Shaped Dev Board

Our single board microcontroller platforms have become smaller over the years, from the relatively large classic Arduino and Beagleboard form factors of a decade ago to the postage stamp sized Feather and ESP boards of today. But just how small can they go? With current components, [Femtoduino] think they’ve cracked it, delivering an ESP32-based board with WiFi and Bluetooth, and an LDO regulator for 5 V operation in a circular footprint that’s only 9 mm in diameter.

There are some compromises from such a paucity of real-estate, of which perhaps the most obvious is a lack of space to make I/O lines available. It has SPI, a UART, and a couple of I/O lines, and aside from an onboard RGB LED that’s it. But SPI is versatile well beyond its number of lines, and even with so little there is much that can be done. Another potential compromise comes from the antenna, a Molex surface-mount component, which is an inevitable consequence of a 9 mm circular board.

There has to come a point at which a microcontroller platform becomes so small as to be unusable, but it’s clear that there is a little further for this envelope to be pushed. We’d love to see what other designers do in response to this board.

Making A Three Cent Microcontroller Useful

The Padauk PMS150C is a terrible microcontroller. There are only six pins, there’s only one kiloword of Flash, 64 bytes of RAM, and it doesn’t do multiplication. You can only write code to this chip once, and the IDE uses 8-bit ints. [Anders] got his hands on some of these chips and decided to do something useful with them. It turns out that you can do a lot with minimal hardware, such as driving 300 RGB LEDs with a three cent microcontroller.

There’s some work trying to make an Open Source toolchain for these chips, but [Anders] decided to just go with the manufacturer IDE and programmer. What to do with a three cent microcontroller, though? Obviously something blinky. [Anders] connected this microcontroller to a strip of Neopixels, or WS2812Bs, but instead of driving them by giving each pixel a few bytes of RAM, the entire strip is being bitbanged one bit at a time. It’s some clever code, and even if [Anders] won’t be able to send images to a gigantic graphic display made of Neopixels, it’s still a neat trick.

At three cents and nearly zero associated hardware, this is the cheapest microcontroller we’ve ever seen. Even the minimalist PIC and AVR parts are on the orders of dozens of cents per part, and they still only have the functionality of this three-cent part. The manufacturer’s page has more details on the microcontroller itself including the data sheet, and you can check out the sizzle reel of this project below.

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Python and the Internet of Things Hack Chat

Join us Wednesday at noon Pacific time for the Python and the Internet of Things Hack Chat!

Opinions differ about what the most-used programming language in right now is, but it’s hard to deny both the popularity and versatility of Python. In the nearly 30 years since it was invented it has grown from niche language to full-blown development environment that seems to be everywhere these days. That includes our beloved microcontrollers now with MicroPython, and Adafruit’s CircuitPython, greatly lowering the bar for entry-level hackers and simplifying and speeding development for old hands and providing a path to a Python-powered Internet of Things.

The CircuitPython team from Adafruit Industries – Dan Halbert​, Kattni Rembor​, Limor “Ladyada” Fried​, Phillip Torrone​, and Scott Shawcroft – will drop by the Hack Chat to answer all your questions about Python and the IoT. Join us as we discuss:

  • How CircuitPython came to be;
  • The range of IoT products that support Python;
  • Getting started with Python on IoT devices; and
  • What’s on the horizon for a Python-powered IoT?

And as extra enticement, we’ll be giving away five free one-year passes to ​Adafruit.io​! We’ll draw five names at random from the list of Hack Chat attendees. Stop by for a chance to win. And, the Adafruit team will be streaming video live during the Hack Chat as well.

You are, of course, encouraged to add your own questions to the discussion. You can do that by leaving a comment on the Python and the Internet of Things Hack Chat and we’ll put that in the queue for the Hack Chat discussion.

join-hack-chatOur Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, April 3, at noon, Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

Want a quick peek at what’s possible with CircuitPython? Check out this PyPortal event countdown timer that just happens to be counting down the hours till the next Hack Chat.

Live Hacking And A MIDI Keytar

We can’t think of where you’d buy a new, cheap, MIDI keytar that’s just a keyboard and a handle with some pitch and mod wheels or ribbon controllers. This is a format that died in the 90s or thereabouts. Yes, the Rock Band controller exists, but my point stands. In fact, the closest you can get to a cheap, simple MIDI keytar is the Alesis Vortex Wireless 2 Keytar, but the buttons on the handle don’t make any sense. [marcan] of Wii and Kinect hacking fame took note. (YouTube, embedded below.)

Reverse engineering is a research project, and all research projects begin with looking at the docs. When it comes to consumer electronics, the best resource is the documents a company is required to submit to the FCC (shout out to FCC.io), which gave [marcan] the user manual, and photos of the guts of the keytar. The ‘system update download’ files are living on the Alesis servers, and that’s really all you need to reverse engineer a keytar.

The first step is extracting the actual device firmware from whatever software package appears on the desktop when you download the software update. This is a simple job for 7zip, and after looking at a binary dump of the firmware, [marcan] discovered this was for an STM chip. With the datasheet of the chip, [marcan] got the entry point for the firmware, some values, and the real hardware hacking began. All of this was done with IDA.

This is a five-hour hacking session of cross-referencing the MIDI spec and a microcontroller built thirty years after this spec was developed. It’s an amazing bit of work just to find the bit of code than handled the buttons on the keytar grip, and it gets even better when the patched firmware is uploaded. If you want to ‘learn hacking’, as so many submitters on our tip line want to do, this is what you need to watch. Thanks [hmn] for the tip.

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Chris Gammell Talks Circuit Toolboxes

Chris Gammell wants to know: What’s in your circuit toolbox?

Personally, mine is somewhat understocked. I do know that in one of my journals, probably from back in the 1980s, I scribbled down a schematic of a voltage multiplier I had just built, with the classic diode and capacitor ladder topology. I probably fed it from a small bell transformer, and I might have gotten a hundred volts or so out of it. I was so proud at the time that I wrote it down for posterity with the note, “I made this today!”

I think the whole point of Chris’ 2018 Hackaday Superconference talk is precisely what I was trying to get at when I made my “discovery” — we all have circuits that just work for us, and the more you have, the better. Most readers will recognize Chris from such venues as The Amp Hour, a weekly podcast he hosts with Dave Jones, and his KiCad tutorial videos. Chris has been in electrical engineering for nearly twenty years now, and he’s picked up a collection of go-to circuits that keep showing up in his designs and making life easier, which he graciously shared with the crowd.

As Chris points out, it’s the little circuits that can make the difference. Slide after slide of his talk had schematics with no more than a handful of components in them, covering applications from dead-simple LED power indicators and switch debouncing to IO expansion using a 74HC595. And as any sensible engineer might, Chris’ toolbox includes a good selection of power protection circuits, everything from polarity reversal protection with a MOSFET and a zener to a neat little high-side driver shutoff using a differential amp and an optoisolator.

My favorite part of the talk was the “Codeless” section — things you can do with discrete components that make microcontroller circuits better. We see the “You could have used a 555!” comments from readers all the time, and Chris agrees, at least to a point. He aptly notes that microcontrollers can wake up with their IO pins in unknown states, and offered several circuits to keep the potential for mischief at bay, such as Schmitt trigger power-on reset or the simple addition of a pull-down resistor to default a MOSFET to a safe state. There’s a lot that code can accomplish, but adding just a few parts can make a circuit much safer and useful.

Chris acknowledges that in any audience, everyone is always at different places with regard to their hardware learning curve, so what’s old hat to someone might be a fresh revelation to another. Still, everything is new to someone at some point, and that’s often the best time to write it down. That’s what I did all those years ago with that voltage multiplier, and it never left me as a result. It’s good advice, and if you haven’t started building your own circuit toolbox, now’s the time.

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