This M5Stack Game Is Surprisingly Addictive

For those of us lucky enough to have been at Hackaday Europe in Berlin, there was a feast of hacks at our disposal. Among them was [Vladimir Divic]’s gradients game, software for an M5Stack module which was definitely a lot of fun to play. The idea of the game is simple enough, a procedurally generated contour map is displayed on the screen, and the player must navigate a red ball around and collect as many green ones as possible. It’s navigated using the M5Stack’s accelerometer, which is what makes for the engaging gameplay. In particular it takes a moment to discover that the ball can be given momentum, making it something more than a simple case of ball-rolling.

Underneath the hood it’s an Arduino .ino  file for the M5Stack’s ESP32, and thus shouldn’t present a particular challenge to most readers. Meanwhile the M5Stack with its versatile range of peripherals has made it onto these pages several times over the years, not least as a LoRA gateway.

An automatic color mixer, dispensing a mixture of red and yellow

The M5Stack Color Maker Can Mix Paint To Match Your Subject

We’ve all learned in primary school art classes that blue and yellow make green, and that adding a little black to a color will make it darker. But what if you want to paint with a color that exactly matches something else? Usually, that requires a lot of trial and error (and paint), and the end result may not look the way you wanted after all.

To help aspiring artists, [Airpocket] made the M5Stack Color Maker. This is a device that reads out a color sensor and automatically mixes watercolor paint in the right proportions to match what it sensed. It dispenses drops of cyan, magenta, yellow and black paint (CMYK) into a small bowl, from which you can then apply it with a paintbrush.

An automatic color mixer, with labels explaining each partThe color sensor is similar in use to the color picker (or “dropper”) tool present in most graphics programs: simply point it at something that has the right color, and it will generate the correct values for you. It is based on an AMS TCS34725 color sensor, which is housed in a 3D-printed shell that also includes a white LED. The sensor outputs Red, Green and Blue (RGB) values, which are converted into the corresponding CMYK values by a Raspberry Pi Pico. A touch-sensitive screen allows the user to make adjustments before activating the paint pumps.

Those pumps are tube pumps, which have been specifically designed (and also 3D printed) to allow them to move tiny amounts of liquid while minimizing the pulsing motion typical with this type of pump. They are driven by stepper motors which are controlled by the Pi Pico.

Although many artists might prefer to mix their colors manually, the M5Stack makes mixing that exact shade of blue just that little bit easier. We can also imagine it might help those who are color blind and unable to clearly tell different colors apart. We’ve seen simple paint mixers for larger quantities of paint, and even robots that can do the actual painting for you. If you need a refresher on color theory, we’ve got you covered too.
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M5Stack Device Disassembled

Putting M5Stack On LoRa And The Things Network

LoRa is the new hotness in low-power, long-range communications. Wanting to let the packets fly, [Xose] was faced with a frequecny problem and ended up developing a Europe-friendly LoRa module for the M5Stack system. The hardware is aimed at getting onto The Things Network, a LoRa based network that provides connectivity for IoT devices. While there was an existing M5Stack module for LoRa, it only supported 433 MHz. Since [Xose] is in Europe, an 868 MHz or 915 MHz radio was needed. To solve this, a custom board was built to connect the HopeRF RFM69 series of modules to the M5Stack.

If you haven’t heard of it before, the M5Stack platform is a stackable development board platform. Like Arduino, you can add functionality by stacking PCBs using a standard header. Unlike Arduino, M5Stack fits in a case nicely and is designed for building devices with user interfaces. For $35, you get an ESP32 based system with WiFi, Bluetooth, a color LCD, battery, buttons, a speaker, and IO connectors.

With the hardware in place, [Xose] 3D printed a custom case to hold the board and added it to the stack. The firmware acts as a monitor for The Things Network, showing live coverage. The final product looks very clean for a prototype, maintaining the finished look of M5Stack.

The firmware, board design, and case design files for the project are all available on Github.

Close up of a Sony FX-300 'Jackal' radio

Packing Even More Features Into A Classic Radio

When it comes to hacking niches, breathing new life into vintage devices is always an exciting challenge. [t0mg]’s recent project exemplifies this with his 1978 Sony FX-300 ‘Jackal’ radio. He’d already upgraded the radio in 2021 and turned it into a feature-packed marvel, but there’s always room for improvement.

[t0mg]’s initial 2021 build had its quirks: noisy sound, a subpar display, and a non-functional radio module. Determined to enhance these aspects, he sourced an IPS version of the original 3.2″ ILI9431 LCD, significantly improving viewing angles. To tackle the audio issues, he integrated an M5Stack Atom microcontroller, utilizing its Bluetooth A2DP capabilities to deliver cleaner digital sound via I2S to the Teensy audio board. The Teensy itself got a complete wire overhaul just for the sake of good craftmanship.

The new setup also enabled the display of song metadata. Additionally, [t0mg] incorporated a dedicated Arduino Nano clone to manage inputs, streamlining the overall design. The revamped ‘Jackal’ now boasts a bunch of impressive features such as displaying RDS data for FM stations, voice recording, and an NFC reader for personalized playlists.

If you’re into radio makeovers, look into this post for a real golden oldie, or start out with the basics. For [t0mg]’s earlier improved version of this Jackal, read our article on it here.

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Tactility; The ESP32 Gets Another OS

Doing the rounds this week is a new operating system for ESP32 microcontrollers, it’s called Tactility, and it comes from [Ken Van Hoeylandt]. It provides a basic operating system level with the ability to run apps from an SD card, and it has the choice of a headless version or an LVGL-based touch UI.

Supported devices so far are some Lillygo and M5Stack boards, with intriguingly, support in the works for the Cheap Yellow Display board that’s caught some attention recently. The term “ESP32” is now a wide one encompassing Tensilica and RISC-V cores and a range of capabilities, so time will tell how flexible it is for all branches of the family.

We find this OS to be interesting, both in its own right and because it joins at least two others trying to do the same thing. There’s [Sprite_TM]’s PocketSprite mini console, and the operating system used by the series of Netherlands hacker camp badges,  We’ll be trying to get a device running it, in order to give you a look at whether it’s suitable for your projects. If it runs well on the cheaper hardware, it could be a winner!

Exercise Wheel Tracker Confirms Suspicions About Cats

What do cats get up to in the 30 minutes or so a day that they’re awake? Being jerks, at least in our experience. But like many hackers, [Brent] wanted to quantify the activity of his cat, and this instrumented cat exercise wheel was the result.

To pull this off, [Brent] used what he had on hand, which was an M5Stack ESP32 module, a magnetic reed switch, and of course, the cat exercise wheel [Luna] seemed to be in the habit of using at about 4:00 AM daily. The wheel was adorned with a couple of neodymium magnets to trip the reed switch twice per revolution, with the pulse stream measured on one of the GPIOs. The code does a little debouncing of the switch and calculates the cat’s time and distance stats, uploading the data to OpenSearch for analysis and visualization. [Brent] kindly includes the code and the OpenSearch setup in case you want to duplicate this project.

As for results, they’re pretty consistent with what we’ve seen with similar cat-tracking efforts. A histogram of [Luna]’s activity shows that she does indeed hop on the wheel at oh-dark-thirty every day, no doubt in an effort to assassinate [Brent] via sleep deprivation. There’s also another burst of “zoomies” around 6:00 PM. But the rest of the day? Pretty much sleeping.

A Simple Laser Harp MIDI Instrument

Craig Lindley is a technical author and a prolific maker of things. This simple project was his first attempt to create a laser harp MIDI device. While on vacation, Craig saw a laser harp with only three strings and decided to improve upon it by expanding it to twelve strings. The principle of operation is straightforward: twelve cheap diode laser modules aim a beam towards an LDR, which changes resistance if the light level changes when the beam is interrupted.

The controller is a simple piece of perf board, with a Wemos D1 mini ESP32 module flanked by some passives, a barrel socket for power, and the usual DIN connector for connecting the MIDI instrument. Using the ESP32 is a smart choice, removing all the need for configuration and user indication from the physical domain and pushing it onto a rarely-needed webpage. After a false start, attempting to use a triangular frame arrangement, [Craig] settled upon a simple linear arrangement of beams held within a laser-cut wooden box frame. Since these laser modules are quite small, some aluminium rod was machined to make some simple housings to push them into, making them easier to mount in the frame and keeping them nicely aligned with their corresponding LDR.

Sadly, the magnetic attachment method [Craig] used to keep the LDRs in place and aligned with the laser didn’t work as expected, so it was necessary to reach for the hot glue. We’ve all done that!

An interesting addition was using an M5 stack Unit-Synth module for those times when a proper MIDI synthesiser was unavailable. Making this luggable was smart, as people are always fascinated with laser harps. That simple internal synth makes travelling to shows and events a little easier.

Laser harps are nothing new here; we have covered plenty over the years. Like this nice build, which is more a piece of art than an instrument, one which looks just like a real harp and sounds like one, too, due to the use of the Karplus-Strong algorithm to mimic string vibrations.