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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Stage Lighting Hack Keeps La Bohème From Becoming A Dumpster Fire

October 22, 2023 by Dan Maloney 20 Comments

With all due respect to the Utah Opera’s production of La bohème, we just couldn’t resist poking a little fun at master electrician [David Smith]’s quick lighting hack for the opera. And who knew an opera from 1896 would need a garbage can fire? Live and learn.

In what appears to be a case of “The show must go on,” [David] was called on to improve an existing fire effect for one scene in the opera, which was reportedly a bit “artificial and distracting.” This is a pretty common problem in live productions of all types; it’s easy to throw light at a problem, but it’s often hard to make it both convincing and unobtrusive. Luckily, he had both the time to come up with something, and a kit full of goodies to make it happen. A balled-up strip of Neopixels provided the light, with an Arduino running some simple code to randomize the intensity and color of the RGBs. [David] stuck with the warm white, red, and green colors, to keep the color temperature about right for a fire, and drove the LEDs with a couple of MOSFETs that he keeps in his kit to fix busted dimmer packs.

The overall effect worked well, but the holes knocked in the side of the greatly abused garbage can let too much light out, making the effect distracting on stage. The remedy was simple: a cylinder of printer paper surrounding the LED tape. The paper not only acted as a diffuser but held the tape in place inside the can. The electrical crew ran two circuits to the can — one to keep the Arduino running throughout the show, and one to power the LED tape. The former made sure the audience didn’t see the microcontroller boot sequence, and the latter gave the electrician a way to control the effect from the dimmer console. The brief video below shows it in action during a rehearsal.

Hats off to [David] and the whole crew for the stagecraft heroics and for getting this thrown together so quickly.

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A WiFi RGB Camera Grip Is Probably Not Ideal For Night Shoots

August 29, 2023 by Lewin Day 1 Comment

RGB LEDs can be found on everything from motherboards to sticks of RAM these days. [dslrdiy] wanted to bring this same visual flair to his camera setup, so built what he’s calling the world’s first RGB camera grip.

The build is based on an existing off-the-shelf camera grip. It’s disassembled for the build, with a pair of 18650 lithium batteries installed inside as a power supply. They run a small DC-DC converter, which powers a Raspberry Pi Zero and a WS2812B LED strip which provides the lovely colorful lighting effects. The LEDs light up a translucent spacer installed in the camera grip solely for the purpose of aesthetics.

So far, so straightforward. However, [dslrdiy] also implemented one more useful feature. The Pi Zero is able to scrape photos from the camera, and automatically load them on to a Windows network share. That’s a nice zero-fuss way to get pictures off your camera when you return to your home network.

We’re not sure too many professional photographers will rush after the RGB grip, as it’s often poor practice to introduce strange uncontrolled colorful lights into a scene. However, the wireless tethering feature does seem attractive depending on your usual workflow. Video after the break.

Continue reading “A WiFi RGB Camera Grip Is Probably Not Ideal For Night Shoots” →

Enhance VR Immersion By Shoehorning An Ambilight Into A Headset

July 9, 2023 by Donald Papp 6 Comments

Everyone wants a wider field of view in their VR headsets, but that’s not an easy nut to crack. [Statonwest] shows there’s a way to get at least some of the immersion benefits with a bit of simple hardware thanks to the VR Ambilight.

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