Fast LED Matrix Graphics For The ESP32

Many of you will have experimented with driving displays from your microcontroller projects, and for most people that will mean pretty simple status information for which you’d use standard libraries and not care much about their performance. If however any of you have had the need for quickly-updating graphics such as video or game content, you may have found that simpler software solutions aren’t fast enough. If you are an ESP32 user then, [Louis Beaudoin] may have some good news for you, because he has ported the SmartMatrix library to that platform. We’ve seen his demo in action, and the results as can be seen in the video below the break are certainly impressive.

In case you are wondering what the SmartMatrix library is, it’s an LED matrix library for the Teensy. [Louis]’s port can be found on GitHub, and as he was explaining to us over a beer at our Cambridge bring-a-hack, it takes extensive advantage of the ESP32’s DMA capabilities. Making microcontrollers talk with any sort of speed to a display is evidently a hot topic at the moment, [Radomir Dopieralski]’s talk at our Dublin Unconference a few weeks ago addressed the same topic.

We have to admit a soft spot for LED panels here at Hackaday, and given the ESP32’s power we look forward to writing up the expected projects that will come our way using this library.

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Automating The Design Of Word Clocks

Word clocks, or a matrix of light-up letters that spell out the time, are a standard build for all enterprising electronics enthusiasts. The trouble is finding the right way to drive a matrix of LEDs and the significant amount of brainpower that goes into creating a matrix of letters that will spell out the time without making it look like it’s supposed to spell out the time.

For his Hackaday Prize entry this year, [Stephen Legge] is creating a standard toolkit that makes word clocks easier to build. It’s a hardware and software project, allowing for LED matrices of any reasonable size, and the software to make a grid of letters that only spells out the words you want and not the four-letter ones you don’t.

The hardware for this project is built around the IS31FL3733 LED driver from ISSI. This is an interesting chip that takes I2C in and spits out a LED matrix with very few additional support components. This chip provides [Stephen] with a 12×16 single-color LED matrix, which is more than enough for a word clock.

Where this build gets slightly more interesting is the creation of a custom matrix of letters that will still spell out ‘quarter to noon’ when lit in the appropriate way. This is a big challenge in creating a customized word clock; you could always borrow the layout of the letters from another word clock, but if you want customized phrases, you’ll either have to sit down with a pencil and graph paper, or write some software to do it automatically.

It’s a great project, and since all of [Stephen]’s work is being released under Open Source licenses, it’s a great entry to the first portion of the Hackaday Prize where we’re challenging hardware creators to build Open Hardware.

4-Stroke Clock Fires On All Cylinders

We love a good clock build around here, especially if it tells time in a unique way. This 4-stroke digital clock designed by [lagsilva] takes the checkered flag in that category. As it displays the time, it also demonstrates the operation of an internal combustion engine. The numbers take the form of pistons and dance an endless repetition of intake, compression, combustion, exhaust.

The clock’s digits are made from two LED matrices driven by an Arduino Uno and a couple of MAX7219 driver boards. The dots that form the digits move up and down the matrices in 1-3-4-2 firing order. As each piston-digit reaches top dead center, its number lights up. This makes it easy to see the firing order, even at higher RPM values.

Our favorite thing about this clock is the variable RPM setting. There’s a 10k pot around back that adjusts the speed of the pistons between 100 and 800 RPM, and it’s configured to accurately represent piston movement at each increment. Floor it past the break to watch the clock rev up and slow back down.

Although it’s difficult to read the time at 800 RPM, it’s awesome to see a real-time visualization of cylinder movement at the average idle speed of a passenger car. We think it might be neat to rev the engine another way, like with an arcade throttle lever or a foot pedal.

If you like the idea of a constantly-moving clock but prefer an analog readout, take a minute to look at this clock without a face.

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Count YouTube Subscribers with this Red Play Button Award

Professional YouTubers live and die by the number of subscribers they have. It seems like a brutal way to make a living to us, but to each his own. Still, if you’re going to do it, you might as well do it right, and keeping track of how you’re doing with this Play Button Award subscriber counter might make sense. Or it might drive you nuts.

YouTuber [ibuynewstuff] has reached the vaunted 100,000 subscriber mark, the number required to earn the Silver Play Button award. Sadly, 100k is the bare minimum needed to get YouTube’s attention, and tales of waiting for months for the award to arrive are not uncommon. [ibuynewstuff] worked around the issue by 3D-printing his own temporary play button badge. Mounted to a picture frame with an ESP8266 and an 8 x 80 LED display behind a diffuser, [ibuynewstuff] can keep track of his progress toward the Gold Play Button award at 1,000,000 subs. Hopefully, his Silver award will arrive before then.

Want to replicate this but would rather have something a little more permanent than a plastic play button? Try casting your own Copper Play Button award.

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Multifunction Raspberry Pi Chiptune Player

General Instrument’s AY-3-8910 is a chip associated with video game music and is popular with arcade games and pinball machines. The chip tunes produced by this IC are iconic and are reminiscent of a great era for electronics. [Deater] has done an amazing job at creating a harmony between the old and new with his Raspberry Pi AY-3-8910 project.

[Deater] already showed us an earlier version of the project on a breadboard however after having made some PCBs and an enclosure the result is even more impressive. The system consists of not one but two AY-3-8910 for stereo sound that feed a MAX98306 breakout for amplification. A Raspberry Pi 2 sends six channels worth of data via 74HC595 shift registers driven by SPI. There is a surplus of displays ranging from a matrix to bar graph and even 14-segment displays. The entire PCB is recognized as a hat courtesy an EEPROM which sits alongside a DS1307 RTC breakout board. The enclosure is simple but very effective at showing the internals as well as the PCB art.

The software that [Deater] provides, extends the functionality of the project beyond the chiptunes player. There is a program to use the devices as an alarm clock, CPU meter, electronic organ and even a playable version of Tetris as seen in the demo video below. The blog post is very informative and shows progress in a chronological fashion with pictures of the design at various stages of development. [Deater] provides a full set of instructions as well as the schematic along with code posted on GitHub.

If you have a soft spot for the Arduino you may want to check out the 8-bit version of a chip tune player and if you are craving some old hardware peripheral information, do check out the computer curiosities from the Iron Curtain periodContinue reading “Multifunction Raspberry Pi Chiptune Player”

DIY Grid Eye IR Camera

Tindie is a great place to find uncommon electronic components or weird/interesting boards. [Xose Pérez] periodically “stroll the isles” of Tindie to keep up on cool new components, and when he saw Panasonic’s Grid_EYE AMG88 infrared sensor, [Xose] knew that he had to build something with it. The awesome find is an 8×8 IR array sensor on a breakout board… the hack is all in what you do with it.

Already taken by “LED fever,” [Xose’s] mind immediately fixated on an 8×8 IR array with an 8×8 LED matrix display. With a vision, [Xose] threw together an IR sensor matrix, a LED matrix, a small microcontroller, a Li-Ion battery, a charger, and a step-up to power the LEDs. What did he end up with? A bulky but nice camera that looks fantastic.

While commercially available IR Cameras have thousands of pixels and can overlay a normal image over an IR image among other fancy stuff, they are sometimes prohibitively expensive and, to quote [Xose], “waaaaaay less fun to build”. Like any engineer, [Xose] still has ideas for how to improve his open source camera. From more color patterns to real time recording, [Xose] is only limited by the memory of his microcontroller.

Moreover, [Xose’s] camera is inspired by the Pibow cases made by Pimoroni and this is only one project in a series that uses a stack of laser cut pieces of MDF and acrylic for the project enclosure. What’s not to love: short fabrication times and a stunning result. Want more project enclosures? We’ve got plenty.

World’s Smallest LED Cube – Again

There’s a new challenger on the block for the title of the “Worlds Smallest 4x4x4 RGB LED Cube“. At 13x13x36 mm, [nqtronix]’s Cube Pendant is significantly smaller than [HariFun’s] version, which measures in at about 17x17x17 mm just for the cube, plus the external electronics. It took about a year for [nqtronix] to claim this spot, and from reading the comments section, it seems [HariFun] isn’t complaining. The Cube Pendant is small enough to be used as a key fob, and [nqtronix] has managed to really cram a lot of electronics in it.

The LED’s used are 0606 RGB’s which are 1.6mm square, although he did consider using 0404’s before scrubbing the idea. There’s many ways of driving 192 IO’s, but in this case, Charlieplexing seemed like the best solution, requiring 16 IO’s. Unlike [HariFun]’s build, this one is fully integrated, with micro-controller, battery and everything else wrapped up in a case made entirely from PCB — inspired by [Voja Antonic]’s FR4 enclosure technique, and the LED array is embedded in clear resin.

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