Driving a Controllerless LCD With the Humble Arduino Uno

These days, you could be forgiven for thinking driving an LCD from a microcontroller is easy. Cheap displays have proliferated, ready to go on breakout boards with controllers already baked in. Load up the right libraries and you’re up and running in a matter of minutes. However, turn your attention to trying to drive a random LCD you’ve yanked out of a piece of old equipment, and suddenly things get harder. [Ivan Kostoski] was in just such a position and decided to get down to work.

[Ivan]’s LCD was a 320×240 STN device salvaged from an old tape library. The display featured no onboard controller, and the original driver wasn’t easily repurposed. Instead, [Ivan] decided to drive it directly from an Arduino Uno.

This is easier said than done. There are stringent timing requirements that push the limits of the 8-bit platform, let alone the need for a negative voltage to drive the screen and further hardware to drive the backlight. These are all tackled in turn, with [Ivan] sharing his tips to get the most flexibility out of the display. Graphics and text modes are discussed, along with optimizations that could be possible through the varied use of available RAM and flash.

The code is available on Github. If you need inspiration for your own controllerless LCD driver. [Ben Heck] has done similar work too, using FPGA grunt to get the job done.

ESP32 Drives Controllerless Display Using I2S Hack

It’s possible to find surplus LCDs in all kinds of old hardware. Photocopiers, printers – you name it, there’s old junk out there with displays going to waste. Unfortunately, unlike the displays on sale at your favourite maker website, these often lack a controller and can be quite difficult to drive. [pataga] took on the challenge to drive a LCD of unknown provenance, using the power of the ESP32.

The LCD in question is a 240×160 monochrome device, that was initially being driven successfully with a Microchip PIC24 with a dedicated LCD driver peripheral. This allowed [pataga] to study the display interface under working conditions with the help of an oscilloscope. Inspiration was then taken from a project by [Sprite_tm], which used the I2S peripheral to drive a small LED display without placing load on the CPU.

Using the ESP32’s I2S peripheral in parallel mode makes it possible to shift data out in the correct format to drive the LCD without bit-banging IO pins and using up precious CPU time. This leaves processor cycles free to do interesting things, like generating 3D images using [cnlohr]’s routines from the Channel 3 project. There’s a little extra work to be done, with the frame signal being generated by an external flip flop and some fudging with the arrangement of various registers, but it’s a remarkably tidy repurposing of the I2S hardware, which seems to be the gift that keeps on giving. (Here it is spitting out VGA video through a resistor DAC.)

Code is available on Github for those looking to get at the nuts and bolts of the hack. It’s another build that goes to show, it’s not the parts in your junk box that count, but how you use them.

Corn Starch Fixes A Game Boy Screen

Nintendo’s Game Boy was the handheld of the 1990s. Like many of their products, it was famous for its ability to stand up to punishment from angry children and military strikes alike. Its biggest weakness is perhaps its unbacklit LCD screen. Retrogamers and chiptuners alike find themselves modifying and replacing these regularly.

A common problem during these swaps is “Newton rings” – an issue where the polarizer comes into contact with the LCD glass, causing unsightly visual artifacts. Thankfully, there is a simple fix. It’s possible to keep the two separated with the application of microscopic particles, too small to see. [esotericsean] uses cornstarch, while [bogamanz] favors diatomaceous earth. For best results, a makeup brush can be used to apply a fine coating, and compressed air used to clean out the Game Boy and remove any excess.

It’s rare to fix a delicate screen problem with a household staple, but gratifying when it works. The results are hard to see on camera, but many report this fixing the frustrating issue. So, if you’re planning to backlight your Game Boy, keep this in your bag of tricks. It’ll allow you to get the best possible result, and may be useful on other old-school LCDs as well. Video after the break.

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Designing Custom LCDs To Repair Retrocomputers

China, we’re told, can make anything. If you need some PCBs in a few weeks, there are a few factories in China that will do it. If you need a nuclear reactor, yep, there’s probably a factory in China that’ll do it because nuclear reactors are listed as one of the items facing new tariffs when imported into the United States. No, I am not kidding. What about LCDs? What about old-school character LCDs? Is it possible to find a factory in China that will make you the LCD you want? That’s what [Robert Baruch] will find out, because he’s repairing an old computer with new parts.

The object of this repair and restomod is a TRS-80 Pocket Computer (PC-1), otherwise known as the Sharp PC-1211. It looks like a calculator, but no, it’s a legitimate computer you can program in BASIC. [Robert] bought this computer for a bit more than $5 on eBay ‘for repair’, which means the zinc-air battery was dead, and unfortunately, the LCD was shot. The LCD technically works, but it just doesn’t look good. Sometime in the last thirty years, moisture got in between the layers of glass, polarizing film, and liquid crystal. This is not unique to [Robert]’s unit — a lot of these PC-1s have the same problem, many of these broken seals rendering the computers themselves useless.

This is an ancient computer, and replacements for this LCD are impossible to find, but because the Sharp PC-1211 is well documented, it is possible to find the datasheet for the original display. With that, it’s just a question of finding an LCD manufacturer that will do it. So far, the costs look good — $800 USD ($300 for tooling and 10 samples, $500 for another 200 LCDs) is what it’ll take to get a few units. [Robert] already has a few people interested in repairing their own Pocket Computers. You can follow the eevblog thread here, or check out the video below.

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Hack A ThinkPad Display

Hackers really like their tools. This leads to holy wars over languages, editors, keyboards, and even laptops. The problem with laptops is that they age, and not always gracefully. [Syonyk] likes his ThinkPad T430S, except for one thing, its TN display wasn’t really very good. These flat screens use an older technology and show color changes with different viewing angles among other problems. So he managed to upgrade the device’s screen to IPS with the help of a replacement screen and an adapter (see right). Apparently, many similar ThinkPads can take the same sort of upgrade.

The problem is that the laptop uses LVDS to talk to the TN screen, while newer screens are likely to use Embedded DisplayPort (eDP) which is a different protocol entirely. However, there’s now a converter that [Syonyk] found on eBay (from China, of course). For about $70, the motherboard’s LVDS output can transform to eDP. Of course, you also need an IPS display panel.

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Meat-Seeking Raspberry Pi Leads you to Flavortown

[Patrick McDavid] and his wife had a legitimate work-related reason for writing some Python code that would pull the exact latitude and longitude of the individual locations within a national retain chain from Google’s Geocoding API. But don’t worry about that part of the story. What’s important now is that this simple concept was then expanded into a pocket-sized device that will lead the holder to the nearest White Castle or Five Guys location.

The device, which [Patrick] lovingly referrers to as the “Cheeseburger Compass”, uses a Raspberry Pi 3, an Adafruit 16×2 LCD with keypad, a GPS module, and the requisite battery and charger circuit to make it mobile. With the coordinates for the various places one can obtain glorious artery clogging meat circles loaded up, the device will give the user the cardinal direction and current distance from the nearest location of the currently selected chain.

[Patrick] has published the source code for this meat-seeking gadget on GitHub, but notes that most of it is just piecing together existing libraries and tools. As with many Python projects, it turns out there’s already a popular library to do whatever it is you were trying to do manually, so his early attempts at calculating distances and bearings were ultimately replaced with turn-key solutions. Though he did come up with a quick piece of code that would convert a compass heading in degrees to a cardinal direction that he couldn’t find a better solution for. Maybe he should make it a library…

Sadly the original Cheeseburger Compass got destroyed from being carried around so much, but at least it died doing what it loved. [Patrick] says a second version of the device would likely switch over to a microcontroller rather than the full Raspberry Pi experience, as it would make the device much smaller and greatly improve on the roughly two hour battery life.

This project reminds us of the various geocache devices we’ve covered in the past, but with the notable addition of hot sizzling meat. Talk about improving on a good thing.

Digital Picture Frame Turned Vectrex Overlay

For Hackaday readers which might not be so well versed in the world of home video gaming before the 1983 crash, the Vectrex was an interesting attempt at bringing vector graphics into player’s living rooms. Priced around $500 in today’s dollars, the machine was unique in that it included its own black and white CRT display rather than requiring the owner to plug it into their television. To spice things up a little bit, games would include a thin plastic overlay you could put over the screen to give the game faux colors. What can we say? It was the 1980’s.

Like many vintage gaming systems, the Vectrex still commands a devoted following of fans, some of which continue to find ways to hack and mod the system nearly 40 years after its release. One such fan is [Arcade Jason], who’s recently been fiddling with the idea of creating a modern take on the overlay concept using a hacked LCD display. While it’s still a bit rough around the edges, it does hold promise. He hopes somebody might even run with the idea and turn it into a marketable product for the Vectrex community.

[Jason] started by getting an old digital picture frame and tearing it down until he liberated the LCD panel. By carefully disassembling it, he was able to remove the backlight and was left with a transparent display. He then installed the panel over the display of the Vectrex, leaving the picture frame’s PCB and controls dangling off to the side. Extending the display’s ribbon cable should be easy enough for a more robust installation.

He then loaded the frame with random psychedelic pictures he found online, as well as some custom overlays which he quickly whipped up using colored blocks in an art program. In the video after the break, [Jason] shuffles through images on the frame using the buttons on the PCB while loading different demos to show the kind of visual effects that are possible.

While a neat concept, there are a couple of issues that need to be resolved before this could really be put into practice. For one, the LCD panel isn’t the proper size or aspect ratio to match the Vectrex display, so it doesn’t cover the whole CRT. It’s also rather difficult to select images to show on the LCD panel; an improved version might use something like the Raspberry Pi to load images on the panel while exposing a control interface on a secondary screen of some type.

This isn’t the first time [Jason] has experimented with the Vectrex, or even the first time he’s tried to add color to the classic system. We’re interested to see what he comes up with next.

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