Microcontrollers

2216 Articles

Add A Little WOPR To Your Server Rack

February 19, 2025 by 29 Comments

Like so many of us, [aforsberg] found themselves fascinated with the WOPR computer from WarGames — something about all those blinking LEDs must speak to nerds on some subconscious level. But rather than admire the light show from afar, they decided to recreate it at a scale suitable for a 1U server rack.

So what goes into this WOPR display? In this case, the recipe simply calls for three MAX7219 dot matrix LED modules and a Raspberry Pi Pico, although you could swap that out for your favorite microcontroller if you wish. You should probably stick with something that at least runs MicroPython though, or else you won’t be able to use the included Python code to mimic the light patterns seen in the film.

What we like most about this project is how simple and inexpensive it is to recreate. There’s no custom PCB, and all the parts are mass produced enough that the economies of scale have made them comically cheap. Even at Amazon prices, you’re looking at around $50 USD in parts, and quite a bit less if you’ve got the patience to order everything through AliExpress.

Critics will note that, in its current state, this display just shows gibberish (admittedly stylish gibberish, but still). But as we’ve seen with similar projects, that’s simply a matter of software.

Space Monitor Points Out Celestial Objects

February 18, 2025 by 22 Comments

Logically we understand that the other planets in the solar system, as well as humanity’s contributions to the cosmos such as the Hubble Space Telescope and the International Space Station, are zipping around us somewhere — but it can be difficult to conceptualize. Is Jupiter directly above your desk? Is the ISS currently underneath you?

If you’ve ever found yourself wondering such things, you might want to look into making something like Space Monitor. Designed by [Kevin Assen], this little gadget is able to literally point out the locations of objects in space. Currently it’s limited to the ISS and Mars, but adding new objects to track is just a matter of loading in the appropriate orbital data.

In addition to slewing around its 3D printed indicator, the Space Monitor also features a round LCD that displays the object currently being tracked, as well as the weather. Reading through the list of features and capabilities of the ESP32-powered device, we get the impression that [Kevin] is using it as a sort of development platform for various concepts. Features like remote firmware updates and the ability to point smartphones to the device’s configuration page via on-screen QR aren’t necessarily needed on a personal-use device, but its great practice for when you do eventually send one of your creations out into the scary world beyond your workbench.

If you’re interested in something a bit more elaborate, check out this impressive multi-level satellite tracker we covered back in 2018.

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A Guide To Making The Right Microcontroller Choice

February 14, 2025 by 50 Comments

Starting a new microcontroller project can be pretty daunting. While you have at least a rough idea of where you want to end up, there are so many ways to get there that you can get locked into “analysis paralysis” and never get the project off the ground. Or arguably worse, you just throw whatever dev board you have in the junk bin and deal with the consequences.

While it’s hard to go wrong with relying on a familiar MCU and toolchain, [lcamtuf] argues in this recent guide to choosing microcontrollers that it’s actually not too much of a chore to make the right choice. Breaking the microcontroller universe down into three broad categories makes the job a little easier: simple process control, computationally intensive tasks, and IoT products. Figuring out where your project falls on that spectrum narrows your choices considerably.

For example, if you just need to read some sensors and run a few servos or solenoids, using something like a Raspberry Pi is probably overkill. On the other hand, a Pi or other SBC might be fine for something that you need wireless connectivity. We also appreciate that [lcamtuf] acknowledges that intangible considerations sometimes factor in, such as favoring a new-to-you MCU because you’ll get experience with technology you haven’t used before. It might not override technical considerations by itself, but you can’t ignore the need to stretch your wings once in a while.

There’s nothing earth-shattering here, but we enjoy think pieces like this. It’s a bit like [lcamtuf]’s recent piece on rethinking your jellybean op-amps.

A Tiny Computer With A 3D Printed QWERTY Keyboard

February 11, 2025 by 10 Comments

The ESP32 family are the microcontrollers which just keep on giving, as new versions keep them up-to-date and plenty of hackers come up with new things for them. A popular device is a general purpose computer with a QWERTY keypad, and the latest of many we’ve seen comes from [StabbyJack]. It’s a credit card sized machine whose special trick is that its keyboard is integrated in the 3D printing of its case. We’ve seen rubber membranes and push in keys, but this one has flexible print-in-place keys that line up on the switches on its PCB.

It’s not complete yet but the hardware appears to be pretty much there, and aside from that keyboard it has an ESP32-S3 and a 1.9″ SPI LCD. When finished it aims for an ambitious specification, with thermal camera and time-of-flight range finder hardware, along with an OS and software to suit. We like it a lot, though we suspect it might be a little small for our fingers.

If you like this project you may appreciate another similar one, and perhaps your version will need an OS.

RC Cars With First Person Video, All With An ESP32

February 6, 2025 by 8 Comments

Those little ESP32-CAM boards which mate the WiFi-enabled microcontroller with a small parallel-interface camera module have been with us for years, and while they are undeniably cool to play with, they sometimes stretch the available performance in trying to process and stream video. [Mattsroufe] has made a very cool project with one of them, not only managing to stream video from a small model car, but also to control the steering and motor by means of servos and a little motor driver.

Sadly it’s not entirely a stand-alone device, as the ESP32 streams video to a web server with some Python code to handle the controls. The server can aggregate several of them on one page though, for perhaps a little real-life quad-screen Mario Kart action if you have enough of the things. We can see that this idea has plenty of potential beyond the mere fun of driving a toy car around though, but to whet your appetite there’s a demo video below.

We’ve seen enough of the ESP32-cam before, but perhaps more as a photographic device.

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T1 Is A RISC-V Cray

February 6, 2025 by 16 Comments

The crux of most supercomputers is the ability to operate on many pieces of data at once — something video cards are good at, too. Enter T1 (short for Torrent-1), a RISC-V vector inspired by the Cray X1 vector machine.

T1 has support for features, including lanes and chaining. The chip contains a version of the Rocket Core for scalar operations, but there’s no official support for using it. The project claims you could easily replace that core with any other RISC-V CPU IP.

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BLE Rain Gauge Sips Water And Batteries

February 3, 2025 by 23 Comments

It isn’t that hard to make an electronic rain gauge if you have a steady source of power or you don’t mind changing batteries often. But [Matthew Ford] offers a third option: a simple device with a Bluetooth Low Energy (BLE) module that can get a few years of a pair of AA batteries.

The approach has several advantages. Batteries make the device self-contained, and changing them infrequently is an obvious win. In addition, the BLE allows the device to be wireless and send data directly to an Android device. Thanks to a WH-SP-RG rain gauge, there’s not much to that part. The smart part is an nRF52832 module and some minor parts. The phone side uses an off-the-shelf Android app.

In a project like this, it is critical to have timers that really put the CPU to sleep. [Matthew] had to modify the Arduino libraries to allow the lp_timer objects to make it to an hour. Without the modifications, the timer can only reach 8.5 minutes. Sure, you could stack them, but that means taking a power hit multiple times an hour which would affect battery life.

Not the most complex project, but more complexity would mean lower battery life, so — as they say — less is more. We couldn’t help but think that with rechargeable batteries and a small solar panel, this could last a very long time.

LoRa, of course, is another choice. You can make 3D print a tipping bucket device, too.