Back to Video Basics with an ESP32 VGA Display

In a world where standards come and go with alarming speed, there’s something comforting about VGA. It’s the least common denominator of video standards, and seeing that chunky DB15 connector on the back of a computer means that no matter what, you’ll be able to get something from it, if you can just find a VGA cable in your junk bin.

But that’s the PC world; what about microcontrollers? Can you coax VGA video from them? Yes, you can, with an ESP32, a handful of resistors, and a little bit of clever programming. At least that’s what [bitluni] has managed to do in his continuing quest to push the ESP32 to output all the signals. For this project, [bitluni] needed to generate three separate signals – red, green, and blue – but with only two DACs on board, he had to try something else. He built external DACs the old way using R/2R voltage divider networks and addressed them with the I2S bus in LCD mode. He needed to make some compromises to fit the three color signals and the horizontal and vertical sync pulses into the 24 available bits, and there were a few false starts, but the video below shows that he was able to produce a 320×240 signal, and eventually goosed that up to a non-native 460×480.

It’s a pretty impressive hack, and we learned a lot about both the ESP32 and the VGA standard by watching the video. He’s previously used the ESP32 to build an AM radio station and to output composite PAL video, and even turned his oscilloscope into a vector display with it. They’re all great learning projects too.

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LEDs and Pi Let You Virtually Decorate This Online Christmas Tree

Anyone who has decorated a Christmas tree knows that the lights are what really make the look. But no matter how many strings you wrap around it, there never seems to be enough. Plus the standard sets either sit there and do nothing, or just blink on and off at regular intervals. Yawn.

But hackers aim higher, and [leo.currie]’s interactive “paintable” Christmas tree takes the lighting game a step beyond. The standard light strings are replaced with strings of WS2811 RGB LEDs which are wired to an ESP8266. A camera connected to a Raspberry Pi is setup up to stream images of the tree to all and sundry on the Interwebz, but with a special twist: it also creates a map of every light on the tree. That allows the lights to be controlled individually in response to user inputs on a web page hosted on the Pi. The upshot is that you can paint the tree with any color you like in real time, or upload various animated GIFs to display on the tree. You can play with the tree directly, or watch a replay on the video below when that Pi inevitably gets hugged to death.

Imagine the possibilities with this. Why not hang a lot of LED strings vertically from the eaves of your house and make a huge, low-resolution display? We’ve featured plenty of large, interactive LED Christmas displays before, and we’d love to see what you come up with.

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Code Review Lamp Subtly Reminds You To Help Your Fellow Developer

[Dimitris Platis] works in an environment with a peer review process for accepting code changes. Code reviews generally are a good thing. One downside though, is that a lack of responsiveness from other developers can result in a big hit to team’s development speed. It isn’t that other developers are unwilling to do the reviews, it’s more that individuals are often absorbed in their own work and notification emails are easily missed. There is also a bit of a “tragedy of the commons” vibe to the situation, where it’s easy to feel that someone else will surely attend to the situation, but often no one does. To combat this, [Dimitris] built this Code Review Lamp, a subtle notification that aims to prod reviewers into action.

The lamp is based on a ring of RGB LEDs and a Wemos D1 Mini board. The Wemos utilizes the popular ESP8266, so it’s easy to develop for. The LED ring and Wemos are tied together with a slick custom PCB. Mounting the LED ring on the top of the PCB and the Wemos on the bottom allows for easy powering via a USB cable while directing light upward.  The assembly is placed in a translucent 3D printed enclosure creating a pleasant diffuse light source.

Every developer gets a Code Review Lamp. The lamps automatically log in to the change management system to check whether anything is awaiting review. If a review is ready, the Lamp glows in a color specific to the individual developer. All this serves as a gentle but persistent reminder that someone’s work is being held up until a review is completed.

We love the way that the device has a clear purpose: it does its job without any unnecessary features or parts. It’s similar to this ESP8266 IoT Motion Sensor in that it has a single job to do, and focuses on it well.

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Circuit Bending A TV For Better Input

If you haven’t noticed, CRTs are getting hard to find. You can’t get them in Goodwill, because thrift stores don’t take giant tube TVs anymore. You can’t find them on the curb set out for the trash man, because they won’t pick them up. It’s hard to find them on eBay, because no one wants to ship them. That’s a shame, because the best way to enjoy old retrocomputers and game systems is with a CRT with RGB input. If you don’t already have one, the best you can hope for is an old CRT with a composite input.

But there’s a way. [The 8-Bit Guy] just opened up late 90s CRT TV and modded it to accept RGB input. That’s a monitor for your Apple, your Commodore, and a much better display for your Sega Genesis.

There are a few things to know before cracking open an old CRT and messing with the circuits. Every (color) CRT has three electron guns, one each for red, green, and blue. These require high voltage, and in CRTs with RGB inputs you’re looking at a circuit path that takes those inputs, amplifies them, and sends them to the gun. If the TV only has a composite input, there’s a bit of circuitry that takes that composite signal apart and sends it to the guns. In [8-bit guy]’s TV — and just about every CRT TV you would find from the mid to late 90s — there’s a ‘Jungle IC’ that handles this conversion, and most of the time there’s RGB inputs meant for the on-screen display. By simply tapping into those inputs, you can add RGB inputs with fancy-schmancy RCA jacks on the back.

While the actual process of adding RGB inputs to a late 90’s CRT will be slightly different for each individual make and model, the process is pretty much the same. It’s really just a little bit of soldering and then sitting back and playing with old computers that are finally displaying the right colors on a proper screen.

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Unphotogenic Lighting As A Feature

Have you ever taken a picture indoors and had unsightly black bars interrupt your otherwise gorgeous photo? They are caused by lighting which flickers in and out in its normal operation. Some people can sense it easier than others without a camera. The inconsistent light goes out so briefly that we usually cannot perceive it but run-of-the-mill camera phones scan rows of pixels in sequence, and if there are no photons to detect while some rows are scanned, those black bars are the result. Annoying, right?

What if someone dressed that bug of light up as a feature? Instead of ruining good photos, researchers at the University of California-San Diego and the University of Wisconsin-Madison have found out what different frequencies of flicker will do to a photograph. They have also experimented with cycling through red, green, and blue to give the effect of a poorly dubbed VHS.

There are ways an intelligent photographer could get around the photo-ruining effect with any smartphone. Meanwhile DSLR cameras are already immune and it won’t work in sunlight, so we are not talking about high security image protection. The neat thing is that this should be easy to replicate with some RGB strips and a controller. This exploits the row scanning of new cameras, so some older cameras are immune.

Blinging Buttons for Pick and Place

With 3D-printing, cheap CNC machines, and the huge variety of hardware available these days, really slick-looking control panels are getting to be commonplace. We’re especially fond of those nice indicators with the chrome bezels, and the matching pushbuttons with LED backlighting; those can really make a statement on a panel.

Sadly for [Proto G], though, the LEDs in his indicator of choice were just boring old one-color units, so he swapped them out and made these addressable RGB indicators. The stock lamps are not cheap units, but they do have a certain look, and they’re big enough to allow room for a little modification. The original guts were removed with a Dremel to make way for a Neopixel board. [Proto G] wanted to bring the board’s pads out to screw terminals, so he had to adapt the 3.0-mm pitch blocks he had on hand to the 2.54-mm pitch on Neopixel board, but that actually came out neater than you’d think. With a little hot glue to stick it all back together, he now has fully-addressable indicators that can be daisy-chained together and only take up a single GPIO pin.

These indicators and the nice looking panel they’re on is part of a delta pick-and-place robot build [Proto G] has been working for a while. He’s had some interesting side projects too, like the clickiest digital clock in the world and easing ESP32 setup for end-users. While we like all his stuff, we can’t wait to write up the finished delta.

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A YouTube Subscriber Counter With A Tetris Twist

When it comes to YouTube subscriber counters, there’s not much wiggle room for creativity. Sure, you can go with Nixies or even more exotic displays, but in the end a counter is just a bunch of numbers.

But [Brian Lough] found a way to jazz things up with this Tetris-playing YouTube sub counter. For those of you not familiar with [Brian]’s channel, it’s really worth a watch. He tends toward long live-stream videos where he works on one project for a marathon session, and there’s a lot to learn from peeking over his virtual shoulder. This project stems from an earlier video, posted after the break, which itself was a condensation of several sessions hacking with the RGB matrix that would form the display for this project. He’s become enamored of the cheap and readily-available 64×32 pixel RGB displays, and borrowing an idea from Mc Lighting author [toblum], he decided that digits being assembled from falling Tetris blocks would be a nice twist. [Brian] had to port the Tetris-ifying code to Arduino before getting the ESP8266 to do the work of getting the subs and updating the display. We think the display looks great, and the fact that the library is open and available means that you too can add Tetris animations to your projects.

None of this is to say that more traditional sub counters can’t be cool too. From a minimalist display to keeping track of all your social media, good designs are everywhere. And adding a solid copper play button is a nice touch too.

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