Microcontrollers

2293 Articles

Tinycorder Isn’t Quite A Tricorder, But…

April 28, 2025 by 12 Comments

The Star Trek tricorder was a good example of a McGuffin. It did anything needed to support the plot or, in some cases, couldn’t do things also in support of the plot. We know [SirGalaxy] was thinking about the tricorder when he named the Tinycorder, but the little device has a number of well-defined features. You can see a brief video of it working below the break.

The portable device has a tiny ESP32 and a battery. The 400×240 display is handy, but has low power consumption. In addition to the sensors built into the ESP32, the Tinycorder has an AS7341 light sensor, an air quality sensor, and a weather sensor. An odd combination, but like its namesake, it can do lots of unrelated things.

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Atomic Clock Trades Receiver For An ESP8266

April 7, 2025 by 20 Comments

The advantage of a radio-controlled clock that receives the time signal from WWVB is that you never have to set it again. Whether it’s a little digital job on your desk, or some big analog wall clock that’s hard to access, they’ll all adjust themselves as necessary to keep perfect time. But what if the receiver conks out on you?

Well, you’d still have a clock. But you’d have to set it manually like some kind of Neanderthal. That wasn’t acceptable to [jim11662418], so after he yanked the misbehaving WWVB receiver from his clock, he decided to replace it with an ESP8266 that could connect to the Internet and get the current time via Network Time Protocol (NTP).

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Multifunctional USB controlled PCB on blue background

How A Tiny Relay Became A USB Swiss Army Knife

April 5, 2025 by 17 Comments

Meet the little board that could: [alcor6502]’s tiny USB relay controller, now evolved into a multifunction marvel. Originally built as a simple USB relay to probe the boundaries of JLCPCB’s production chops, it has become a compact utility belt for any hacker’s desk drawer. Not only has [alcor6502] actually built the thing, he even provided instructions. If you happened to be at Hackaday in Berlin, you now might even own one, as he handed out twenty of them during his visit. If not, read on and build it yourself.

This thing is not just a relay, and that is what makes it special. Depending on a few solder bridges and minimal components, it shape-shifts into six different tools: a fan controller (both 3- and 4-pin!), servo driver, UART interface, and of course, the classic relay. It even swaps out a crystal oscillator for USB self-sync using STM32F042‘s internal RC – no quartz, less cost, same precision. A dual-purpose BOOT0 button lets you flash firmware and toggle outputs, depending on timing. Clever reuse, just like our mothers taught us.

It’s the kind of design that makes you want to tinker again. Fewer parts. More function. And that little smile when it just works. If this kind of clever compactness excites you too, read [alcor6502]’s build log and instructions here.

First PCB With The Smallest MCU?

April 4, 2025 by 30 Comments

[Morten] works very fast. He has already designed, fabbed, populated, and tested a breakout board for the new tiniest microcontroller on the market, and he’s even made a video about it, embedded below.

You might have heard about this new TI ARM Cortex MO micro on these very pages, where we asked you what you’d do with this grain-of-rice-sized chunk of thinking sand. (The number one answer was “sneeze and lose it in the carpet”.)

From the video, it looks like [Morten] would design a breakout board using Kicad 8, populate it, get it blinking, and then use its I2C lines to make a simple digital thermometer demo. In the video, he shows how he worked with the part, from making a custom footprint to spending quite a while nudging it into place before soldering it carefully down.

But he nailed it on the first try, and honestly it doesn’t look nearly as intimidating as we’d feared, mostly because of the two-row layout of the balls. It actually looks easy enough to fan out. Because you can’t inspect the soldering work underneath the chip, he broke out all of the lines to a header to make it quick to check for shorts between those tiny little balls. Smart.

We love to see people trying out the newest hotness. Let us know down in the comments what new parts you’re trying out.

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An ESP32 Pomodoro Timer

March 29, 2025 by 15 Comments

The Pomdoro technique of time management has moved on a little from the tomato-shaped kitchen timer which gave it a name, as [Rukenshia] shows us with this nifty ESP32 and e-paper design. It’s relatively simple in hardware terms, being a collection of off-the-shelf modules in a 3D printed case, but the software has a custom interface for the friend it was built for.

At its heart is a NodeMCU board and a Waveshare display module, with a rotary encoder and addressable LED as further interface components. A lot of attention has been paid to the different options for the interface, and to make the front end displayed on the screen as friendly and useful as possible. Power comes via USB-C, something that should be available in most working environments here in 2025.

We’ve tried a variant on this technique for a while now with varying success, maybe because a mobile phone doesn’t make for as good a timer as a dedicated piece of hardware such as this. Perhaps we should follow this example. If we did, the Hackaday timer couldn’t possibly use an ESP32.

Pi Pico Turns Atari 2600 Into A Lo-fi Photo Frame

March 27, 2025 by 7 Comments

The cartridge based game consoles of decades ago had a relatively simple modus operandi — they would run a program stored in a ROM in the cartridge, and on the screen would be the game for the enjoyment of the owner. This made them simple in hardware terms, but for hackers in the 2020s, somewhat inflexible. The Atari 2600 is particularly troublesome in this respect, with its clever use of limited hardware making it not the easiest to program at the best of times. This makes [Nick Bild]’s Atari 2600 photo frame project particularly impressive.

The 2600 has such limited graphics hardware that there’s no handy frame buffer to place image data into, instead there are some clever tricks evolved over years by the community to build up bitmap images using sprites. Only 64 by 84 pixels are possible, but for mid-70s consumer hardware this is quite the achievement.

In the case of this cartridge the ROM is replaced by a Raspberry Pi Pico, which does the job of both supplying the small Atari 2600 program to display the images, and feeding the image data in a form pre-processed for the Atari.

The result is very 8-bit in its aesthetic and barely what you might refer to as photos at all, but on the other hand making the Atari do this at all is something of a feat. Everything can be found in a GitHub repository.

If new hardware making an old console perform unexpected tricks is your bag, we definitely have more for you.

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Metal Detector Built With Smartphone Interface

March 25, 2025 by 8 Comments

If you think of a metal detector, you’re probably thinking of a fairly simple device with a big coil and a piercing whine coming from a tinny speaker. [mircemk] has built a more modern adaptation. It’s a metal detector you can use with your smartphone instead.

The metal detector part of the project is fairly straightforward as far as these things go. It uses the pulse induction technique, where short pulses are fired through a coil to generate a magnetic field. Once the pulse ends, the coil is used to detect the decaying field as it spreads out. The field normally fades away in a set period of time. However, if there is metal in the vicinity, the time to decay changes, and by measuring this, it’s possible to detect the presence of metal.

In this build, an ESP32 is in charge of the show, generating the necessary pulses and detecting the resulting field. It’s paired with the usual support circuitry—an op-amp and a few transistors to drive the coil appropriately, and the usual smattering of passives. The ESP32 then picks up the signal from the coil and processes it, passing the results to a smartphone via Bluetooth.

The build is actually based on a design by [Neco Desarrollo], who presents more background and other variants for the curious. We’ve featured plenty of [mircemk]’s projects before, like this neat proximity sensor build. Continue reading “Metal Detector Built With Smartphone Interface” →