The BAPPR Keeps Your Addressable LED System Cool

July 27, 2024 by Alexander Rowsell 17 Comments

We all love a nice strip or grid of addressable LEDs. It can add flair or an artistic touch to many projects, and it can make gaming computers look extra 1337. However, providing enough current to a long strip of addressable LEDs can sometimes be difficult. Often a separate voltage rail is needed to supply enough juice. At the same time, continually sending out data to animate them can often use 100% of the microcontroller’s CPU power, especially if the serial bus is being bit-banged. A crash or badly timed interrupt can leave the system in a weird state and sometimes with the LEDs not displaying the correct colours. Or you might just want to enter a power-saving mode from time to time on your main MCU? Well, the BAPPR is designed to address all of these problems.

[TheMariday] created the BAPPR and made it fully open-source. It’s a switch-mode power supply that can accept anywhere from 7 V to 17 V and converts it into a strong 5 V rail for typical addressable LEDs. It also has a “smart” mode where it monitors the data line going to the LEDs to see if there is activity. If for some reason the system stops sending data, the BAPPR can intervene and shut off the power to the LEDs, which can help prevent strange colour combinations from being displayed while the system recovers. Once data starts flowing again, power is restored and the light party can resume.

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How To Cram 945 LEDs Into A Teeny Tiny Vegas-Style Sphere

May 31, 2024 by Donald Papp 18 Comments

[Carl Bugeja] finds the engineering behind the Las Vegas Sphere fascinating, and made a video all about the experience of designing and building a micro-sized desktop version. [Carl]’s version is about the size of a baseball and crams nearly a thousand RGB pixels across the surface.

A four-layer flexible PCB is the key to routing data and power to so many LEDs.

Putting that many addressable LEDs — even tiny 1 mm x 1 mm ones — across a rounded surface isn’t exactly trivial. [Carl]’s favored approach ended up relying on a flexible four-layer PCB and using clever design and math to lay out an unusual panel shape which covers a small 3D printed geodesic dome.

Much easier said that done, by the way. All kinds of things can and do go wrong, from an un-fixable short in the first version to adhesive and durability issues in later prototypes. In the end, however, it’s a success. Powered over USB-C, his mini “sphere” can display a variety of patterns and reactive emojis.

As elegant and impressive as the engineering is in this dense little display, [Carl] has some mixed feelings about the results. 945 individual pixels on such a small object is a lot, but it also ends up being fairly low-resolution in the end. It isn’t very good at displaying sharp lines or borders, so any familiar shapes (like circles or eyes) come out kind of ragged. It’s also expensive. The tiny LEDs may be only about 5 cents each, but when one needs nearly a thousand of them for one prototype that adds up quickly. The whole bill of materials comes out to roughly $250 USD after adding up the components, PCB, controller, and mechanical parts. It’s certainly a wildly different build than its distant cousin, the RGB cube.

Still, it’s an awfully slick little build. [Carl] doubts there’s much value in pursuing the idea further, but there are plenty of great images and clips from the build. Check out the video, embedded below.

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Keep Tabs On PC Use With Custom Analog Voltmeter

April 26, 2024 by Bryan Cockfield 8 Comments

With the demands of modern computing, from video editing, streaming, and gaming, many of us will turn to a monitoring system of some point to keep tabs on CPU usage, temperatures, memory, and other physical states of our machines. Most are going to simply display on the screen but this data can be sent to external CPU monitors as well. This retro-styled monitor built on analog voltmeters does a great job of this and adds some flair to a modern workstation as well.

The build, known as bbMonitor, is based on the ESP32 platform which controls an array of voltmeters via PWM. The voltmeters have been modified with a percentage display to show things like CPU use percentage. Software running on the computers sends this data in real time to the ESP32 so the computer’s behavior can be viewed at a glance. Each voltmeter is also augmented with RGB LEDs that change color from green to red as use increases as well. The project’s creator, [Corebb], also notes that the gauges will bounce around if the computer is under heavy load but act more linearly when under constant load, also helping to keep an eye on computer status.

While the build does seem to rely on a Windows machine to run the software for export to the monitor, all of the code is open-sourced and available on the project’s GitHub page and could potentially be adapted for other operating systems. And, as far as the voltmeters themselves go, there have been similar projects in the past that use stepper motors as a CPU usage monitor instead.

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Displays We Love Hacking: Parallel RGB

January 25, 2024 by Arya Voronova 8 Comments

You might have seen old display panels, from 3″ to 10″, with 40-pin FFC connectors where every pin seems to be used for some data signal. We call these displays parallel RGB, or TTL RGB, or DPI, and you can find them in higher-power MCU, Raspberry Pi, and other Linux SBC projects. You deserve to know what to do with those – let’s take a look.

The idea is simple – this interface requires you to constantly send a stream of pixels to the display, and you need to send those pixels through a parallel bus. You can send up to 8 bits per color channel per pixel, which makes for 24 bits, and the 24-bit mode is indeed the standard, but in practice, many parallel RGB implementations don’t bother with more than 5-6 bits of color – two common kinds of parallel RGB links are RGB565 and RGB666. The parallel RGB interface is a very straightforward approach to sending pixels to your display, and in many cases, you can also convert parallel RGB to LVDS or VGA interfaces relatively easily!

If you’re new to it, the easiest way you can drive a parallel RGB display is from a Raspberry Pi, where the parallel RGB interface is known as DPI. This is how 800 x 480 display Pi HATs like the Pimoroni HyperPixel work – they use up almost all of the GPIOs on your Pi, but you get a reasonably high-resolution display with a low power footprint, and you don’t need any intermediate ICs either. FPGAs and some higher-grade MCUs also often have parallel RGB output capability, and surely, someone could even use the RP2040 PIO as well!

Throughout the last decade, parallel RGB has been used less and less, but you will still encounter it – maybe you’re working with an old game console like the PSP and would like to put new guts into it, maybe you’re playing with some tasty display that uses parallel RGB, or maybe you’d like to convert parallel RGB into something else while treating it with respect! Let’s go through what makes parallel RGB tick, what tools you have got to work with it, and a few tips and tricks. Continue reading “Displays We Love Hacking: Parallel RGB” →

Hackaday Links: January 7, 2024

January 7, 2024 by Dan Maloney 27 Comments

Oh, perfect — now our cars can BSOD. At least that’s how it looks from a forum post showing a Blue Screen of Death on a Ford Mustang Mach E, warning that an over-the-air software update failed, and now the car can’t be driven. The BSOD includes a phone number to reach Ford’s Customer Relationship Center and even presents a wall of text with specific instructions to the wrecker driver for loading the bricked vehicle onto a flatbed. Forum users questioned the photo’s veracity, but there are reports of other drivers getting bricked the same way. And we’ve got to point out that even though this specific bricking happened to an EV, it could just have easily happened to an ICE vehicle too; forum members were particularly prickly about that point. It would be nice if OTA software updates on vehicles could always roll back to the previous driveable state. Still, we suppose that’s not always possible, especially if memory gets corrupted during the update. Maybe the best defense against a bricked vehicle would be to keep a beater around that doesn’t need updates to keep running.

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Mini Meters Monitor Microprocessor Maximization

December 4, 2023 by Adam Fabio 11 Comments

[Lex] over at Computing: The Details loves to make fun projects. Recently, they have created a hardware CPU monitor that displays how PCs are parallelizing compile tasks at a glance. The monitor is built from 14 analog meters, along with some WS2812 RGB LEDs.

Each meter represents a core on [Lex]’s CPU, while the final two meters show memory and swap usage. The meters themselves are low-cost 5 mA devices. Of course, the original milliamps legends wouldn’t do much good, so [Lex] designed and printed graduations that glue over the top. The RGB LED strip is positioned so two LEDs fit under each meter. The LEDs allow a splash of color to draw attention to the current state of the machine. The whole bank going red would sure get our attention!

The system is controlled by an Arduino Mega, with the meters driven using the PWM pins. The only extra part is a 1 kΩ resistor. The Arduino wrangles the LEDs as well. Sadly [Lex] did not include the software. They did describe it though. Basically they are using a Rust program to call systemstat, obtaining the current CPU utilization data in Linux. A bit of math converts this into pointer values and LED colors. The data is then sent via USB-serial to the Arduino Mega. The software savvy will say it’s pretty easy to replicate, but the hardware-only hackers among us might need a bit of help.

This isn’t the first custom meter we’ve seen on Hackaday. Your author’s first project covered by Hackaday was for a meter created using an automotive gauge stepper motor. I didn’t include source code either – but only because [Guy Carpenter]’s Switec X25 library had me covered.

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ColorReplica Is A Rainbow At Your Fingertips

November 16, 2023 by Kristina Panos 15 Comments

Have you ever wanted to match paint to the color of a pillow, or make a website where the primary color matches your favorite shade of electrolytic capacitor? Then ColorReplica is the project for you.

At the heart of this build are two ESP32s, one of which controls the color picker, and the other lights up the 18 WS2812 LEDs and displays information on the OLED screen.

ColorReplica has two modes, ColorPicker and ColorCube. In ColorPicker mode, you just choose what color you want, adjust the brightness level, and choose between static and dynamic modes for the LEDs. [CiferTech] used the ESP32 touch pins extended to pads on the PCB to control different menu variables, which is a nice touch.

In ColorCube mode, there’s a secondary circuit with a color sensor an another ESP32. Once detected, it transmits the color data to the main device at the push of a button. The RGB LEDs turn that color, and shows the RGB, HEX, and HSV values on the OLED screen. If you’d like to make one of these yourself, everything is available on GitHub.

Want something a big more tangible? Check out this color picker that types HEX codes for you.

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