Button Debouncing With Smart Interrupts

January 4, 2025 by Bryan Cockfield 55 Comments

Debouncing button or switch inputs on microcontrollers can be a challenging problem for those first starting to program these devices. Part of the reason for this difficulty is that real-world buttons don’t behave like the idealized textbook components we first learn about, and therefore need special consideration to operate like one would expect. There are simple ways to debounce inputs like adding a delay after a button is pressed, but for more efficient use of computer resources as well as adding some other capabilities to inputs you might want to look at this interrupt service routine (ISR) method from [Lee] aka [stockvu].

The strategy with this debounce method is not simply to use a single ISR for the button input, but to activate a second timer-based ISR at that time that runs at a certain interval which timestamps any button press and checks the amount of time the button has been active. If it’s under a certain threshold the ISR assumes it’s caused by bounce and blocks the bounce. If the timestamp ages past another longer threshold it knows the button has been released. This method allows on-the-fly adaptation between long button presses and rapid button presses and is capable of debouncing both types.

For those wanting to try this out, [stockyu] has included some example Arduino code for others to use. It’s an interesting take on a solution for a common problem, and puts very little load on the microcontroller. There are about as many ways to debounce inputs as there are microcontroller platforms, though, and you can even use a 555 timer to get this job done which frees up 100% of the microcontroller’s CPU.

Front and rear views of a lander circuit sculpture that retrieves weather data and displays it on a screen.

Landing Soon: This Beautiful Weather Display

January 3, 2025 by Kristina Panos 5 Comments

All wiring is beautiful, except when it isn’t. But is there anything more lovely to behold than circuit sculpture? Once again, [Mohit Bhoite] has made this process look easy like Sunday morning. This time, he’s created a weather display in the form of a lander.

This lander runs on the Particle Photon 2, which connects over Wi-Fi and retrieves the weather forecast for the day, along with sunrise and sunset times and wind conditions. Everything is beautifully displayed on a vertically-oriented Adafruit 170×320 TFT screen.

There’s also a pulse-density microphone (PDM) breakout board and a buzzer, and the build is capped off with a red 0805 LED. We’re not sure what the feet are made of, but they sure make this lander cute (and accurate).

All the project logs are picture-rich, which is really the most we could ask for when trying to imitate this level of greatness. This is apparently an ongoing project, and we’re excited for the end result, although it looks fairly complete from here.

Do you want to bend it like Bhoite? Then be sure to check out his Hackaday Supercon talk on the subject.

Pico Pal Puts RP2350 Into Game Boy Color Shell

January 3, 2025 by Tom Nardi 14 Comments

While modern gaming systems deliver ever more realistic experiences, there’s still something to be said for the consoles and handhelds of the 80s and 90s. For many, the appeal is nostalgic. Others are attracted to the “lo-fi” graphical and sound design of these games, necessitated by the limited hardware of the time.

That said nobody would claim those old systems were perfect. Which is why a hybrid approach like [Peter Khouly] has been working on with the Pico Pal might be the ultimate solution. This replacement motherboard for the Game Boy Color (GBC) is powered by the RP2350, meaning the external hardware will have the same look and feel as it did back in 1998, but you’ll still be able to reap the benefits of modern emulation.

While the origins of the project go a bit farther, [Peter] has been working on this particular variation of the Pico Pal GBC since August, and has kept a fascinating log of his progress. Just getting the RP2350 to emulate Pokémon isn’t really that big of a deal, but getting all the ancillary hardware implemented and fitted inside the case of the GBC is a different story. Especially since [Peter] intends to pack plenty of features into the final product, such as rechargable batteries, Bluetooth audio, real-time clock support, and digital video out.

The most recent status update is from just last week, where [Peter] goes over some of the new features he’s been working on. A major one is the soft power solution, where the physical power switch doesn’t just pull the plug like it did back in the 1990s. Instead, the switch triggers the board to save the game and enter into a low-power mode so that it can come right back on to where you left off. This does impact battery life, but so far, it looks like the Pico Pal GBC will be able to run for at least five hours on a charge, and more than twice that if you don’t mind turning off the audio.

It sounds like there’s still several gremlins to track down in the design, but even in its current state, the Pico Pal GBC looks very interesting. We’re immediately reminded of the phenomenal work [Bucket Mouse] has put in on a similar refit for the original DMG-1 Game Boy.

LED Wall Clock Gets Raspberry Pi Pico Upgrade

January 1, 2025 by Tom Nardi 11 Comments

When [Rodrigo Feliciano] realized that the reason his seven-segment LED wall clock wasn’t working was because the original TG1508D5V5 controller was fried, he had a decision to make. He could either chuck the whole thing, or put in the effort to reverse engineer how the displays were driven and replace the dead controller with something a bit more modern. Since you’re reading this post on Hackaday, we bet you can guess which route he decided to take.

If you happen to own the same model of clock as [Rodrigo], then you really lucked out. He’s done a fantastic job documenting how he swapped the original controller out for a Raspberry Pi Pico W, which not only let him bring the clock back to life, but let him add new capabilities such as automatic time setting via Network Time Protocol (NTP).

But even if you don’t have this particular clock there’s probably something you can learn from this project, as it’s a great example of practical reverse engineering. By loading a high-resolution image of the back of the PCB into KiCad, [Rodrigo] was able to place all the components into their correct positions and following traces to see what’s connected to what.

Pretty soon he not only had a 3D model of the clock’s PCB, but a schematic he could use to help wire in the Pi Pico. Admittedly this is a pretty straightforward PCB to try and reverse engineer, but hey, you have to start somewhere.

We had high hopes for KiCad’s image import feature when it was introduced, and it’s great to see real-world examples like this trickle in as more folks learn about it.

Continue reading “LED Wall Clock Gets Raspberry Pi Pico Upgrade” →

VPlayer Puts Smart Display In Palm Of Your Hand

December 31, 2024 by Tom Nardi 18 Comments

It’s not something we always think about, but the reality is that many of the affordable electronic components we enjoy today are only available to us because they’re surplus parts intended for commercial applications. The only reason you can pick up something like a temperature sensor for literal pennies is because somebody decided to produce millions of them for inclusion in various consumer doodads, and you just happened to luck out.

The vPlayer, from [Kevin Darrah] is a perfect example. Combining a 1.69 inch touch screen intended for smartwatches with the ESP32-S3, the vPlayer is a programmable network-connected display that can show…well, pretty much anything you want, within reason. As demonstrated in the video below, applications range from showing your computer’s system stats to pulling in live images and videos from the Internet.

Continue reading “VPlayer Puts Smart Display In Palm Of Your Hand” →

38C3: Xobs On Hardware Debuggers

December 29, 2024 by Elliot Williams 3 Comments

If you just want to use a debugger for your microcontroller project, you buy some hardware device, download the relevant driver software, and fire up GDB. But if you want to make a hardware debugger yourself, you need to understand the various target chips’ debugging protocols, and then you’re deep in the weeds. But never fear, Sean [Xobs] Cross has been working on a hardware debugger and is here to share his learnings about the ARM, RISC-V, and JTAG debugging protocols with us.

He starts off with a list of everything you need the debugger hardware to be able to do: peek and poke memory, read and write to the CPU registers, and control the CPU’s execution state. With that simple list of goals, he then goes through how to do it for each of the target chip families. We especially liked [Xobs]’s treatment of the JTAG state machine, which looks pretty complicated on paper, but in the end, you only need to get it in and out of the shift-dr and shift-ir states.

Continue reading “38C3: Xobs On Hardware Debuggers” →

38C3: Towards An Open WiFi MAC Stack On ESP32

December 28, 2024 by Elliot Williams 15 Comments

At the 38th Chaos Communications Congress, [Frostie314159] and [Jasper Devreker] gave us a nice update on their project to write an open-source WiFi stack for the ESP32. If you’re interested in the ESP32 or WiFi in general, they’ve also got a nice deep dive into how that all works.

On the ESP32, there’s a radio, demodulator, and a media access controller (MAC) that takes care of the lowest-level, timing-critical bits of the WiFi protocol. The firmware that drives the MAC hardware is a licensed blob, and while the API or this blob is well documented — that’s how we all write software that uses WiFi after all — it’s limited in what it lets us do. If the MAC driver firmware were more flexible, we could do a lot more with the WiFi, from AirDrop clones to custom mesh modes.

The talk starts with [Jasper] detailing how he reverse engineered a lot of Espressif’s MAC firmware. It involved Ghidra, a Faraday cage, and a lucky find of the function names in the blob. [Frostie] then got to work writing the MAC driver that he calls Ferris-on-Air. Right now, it’s limited to normal old station mode, but it’s definite proof that this line of work can bear fruit.

This is clearly work in progress — they’ve only been at this for about a year now — but we’ll be keeping our eyes on it. The promise of the ESP32, and its related family of chips, being useful as a more general purpose WiFi hacking tool is huge.