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 Superconference 2023: First Round Of Speakers Announced!

October 5, 2023 by Elliot Williams 7 Comments

Hackaday Supercon 2023 is almost upon us, and looking over the roster of fantastic talks gets us in the mood already. We hope that it has the same effect on you too.

Supercon is the Ultimate Hardware Conference and you need to be there! We’ll announce the rest of the speakers, the workshops, and give you a peek at the badge over the next couple weeks. Supercon will sell out so get your tickets now before it’s too late. And stay tuned for the next round of reveals on Tuesday! Continue reading “Hackaday Superconference 2023: First Round Of Speakers Announced!” →

Weird Lens Allows Light Field Passthrough For VR Headset

August 10, 2023 by Donald Papp 16 Comments

Light Fields are a subtle but critical element to making 3D video look “real”, and it has little to do with either resolution or field of view. Meta (formerly Facebook) provides a look at a prototype VR headset that provides light field passthrough video to the user for a more realistic view of their surroundings, and it uses a nifty lens and aperture combination to make it happen.

As humans move our eyes (or our heads, for that matter) to take in a scene, we see things from slightly different perspectives in the process. These differences are important cues for our brains to interpret our world. But when cameras capture a scene, they capture it as a flat plane, which is different in a number of important ways from the manner in which our eyes work. A big reason stereoscopic 3D video doesn’t actually look particularly real is because the information it presents lacks these subtleties.

Continue reading “Weird Lens Allows Light Field Passthrough For VR Headset” →

Making Your Own VR Headset? Consider This DIY Lens Design

August 1, 2023 by Donald Papp 11 Comments

Lenses are a necessary part of any head-mounted display, but unfortunately, they aren’t always easy to source. Taking them out of an existing headset is one option, but one may wish for a more customized approach, and that’s where [WalkerDev]’s homebrewed “pancake” lenses might come in handy.

Engineering is all about trade-offs, and that’s especially true in VR headset design. Pancake lenses are compact units that rely on polarization to bounce light around internally, resulting in a very compact assembly at the cost of relatively poor light efficiency. That compactness is what [WalkerDev] found attractive, and in the process discovered that stacking two different Fresnel lenses and putting them in a 3D printed housing yielded a very compact pancake-like unit that gave encouraging results.

This project is still in development, and while the original lens assembly is detailed in this build log, there are some potential improvements to be made, so stay tuned if you’re interested in using this design. A DIY headset doesn’t mean you also must DIY the lenses entirely from scratch, and this option seems economical enough to warrant following up.

Want to experiment with mixing and matching optics on your own? Not only has [WalkerDev]’s project shown that off-the-shelf Fresnel lenses can be put to use, it’s in a way good news that phone-based VR is dead. Google shipped over 10 million cardboard headsets and Gear VR sold over 5 million units, which means there are a whole lot of lenses in empty headsets laying around, waiting to be harvested and repurposed.

Hackaday Podcast 227: Open Source Software, Decoupling Caps, DIY VR

July 14, 2023 by Tom Nardi 1 Comment

Elliot Williams and Tom Nardi start this week’s episode by addressing the ongoing Red Hat drama and the trend towards “renting” software. The discussion then shifts to homebrew VR gear, a particularly impressive solar-powered speaker, and some promising developments in the world of low-cost thermal cameras. Stay tuned to hear about color-changing breadboards, an unofficial logo for repairable hardware, and five lines of Bash that aim to unseat the entrenched power of Slack. Finally, we’ll take the first steps in an epic deep-dive into the world of DisplayPort, and take a journey of the imagination aboard an experimental nuclear ocean liner.

Check out the complete show notes below, and as always, let us know what you think in the comments.

Or download the episode directly in glorious DRM-free MP3.

Continue reading “Hackaday Podcast 227: Open Source Software, Decoupling Caps, DIY VR” →

Behold A DIY VR Headset Its Creator Will “Never” Build Again

July 10, 2023 by Donald Papp 13 Comments

Unsatisfied with commercial VR headset options, [dragonskyrunner] did what any enterprising hacker would: gathered parts over time and ultimately made their own. Behold the Hades Widebody (HWD), a DIY PC VR headset that aims for a wide field of view and even manages to integrate some face and eye tracking.

The Fresnel elements hugging the primary lenses provide a way of extending the display into the wearer’s peripheral vision.

[dragonskyrunner] is — and we quote — “NEVER building one of these again.” The reason is easily relatable to anyone who has spent a lot of time and effort creating something special: it does the job it was created for, but it also has limitations and is a lot of work. If one were to do it all over again, there would be a host of improvements and changes to consider. But one won’t be doing it all over again any time soon because it’s done now.

The good news is that [dragonskyrunner] made an effort to document things, so there is at least a parts list and enough details for any suitably motivated hacker to replicate the work and perhaps even put their own spin on it.

The Hades Widebody has a dual-lens arrangement and wide displays that aim to provide a wider field of view than most setups allow. There’s a main lens in front of the user’s eyes and a cut Fresnel lens providing a sort of extension to the side. [dragonskyrunner] claims that while there is certainly not a seamless transition between the lens elements, it does a better job than an Ambilight at providing a sense of visuals extending into the wearer’s peripheral vision.

The DIY spirit of making a piece of hardware to suit one’s own needs is exactly the sort of thing that would fit into our 2023 Cyberdeck content, and while a headset by itself isn’t quite enough to qualify (devices must have some form of usable input and output), it just might get those creative juices flowing.

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.

Continue reading “Enhance VR Immersion By Shoehorning An Ambilight Into A Headset” →