lcd

328 Articles

“Cheap Yellow Display” Builds Community Through Hardware

October 28, 2023 by 29 Comments

For the most part, Hackaday is all about hardware hacking projects. Sometimes, though, the real hack in a project isn’t building hardware, but rather building a community around the hardware.

Case in point: [Brian Lough]’s latest project, which he dubs “CYD,” for the “cheap yellow display” that it’s based on; which is a lot easier to remember than its official designation, ESP32-2432S028R. Whatever you call it, this board is better than it sounds, with an ESP32 with WiFi, Bluetooth, a 320×480 resistive touch screen, and niceties like USB and an SD card socket — all on aforementioned yellow PCB. The good news is that you can get this thing for about $15 on Ali Express. The bad news is that, as is often the case with hardware from the Big Rock Candy Mountain, the only documentation available comes from a website we wouldn’t touch with a ten-foot pole.

To fix this problem, [Brian] started what he hopes will be a collaborative effort to build a knowledge base for the CYD, to encourage people to put these little gems to work. He has already kick-started that with a ton of quality documentation, including setup and configuration instructions, tips and gotchas, and some sample projects that put the CYD’s capabilities to the test. It’s all on GitHub and there’s already at least one pull request; hopefully that’ll grow once the word gets out.

Honestly, these look like fantastic little boards that are a heck of a bargain. We’re thinking about picking up a few of these while they last, and maybe even getting in on the action in this nascent community. And hats off to [Brian] for getting this effort going.

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Adobe Scientist Cuts A Dash With LCD Shifting Dress

October 22, 2023 by 63 Comments

Adobe research scientist [Christine Dierk] showed off an interesting new project at the Adobe Max conference: Project Primrose, a dress covered with a series of liquid crystal panels that could react to movement, changing the design of the dress. Now, Adobe has released a paper showing some of the technical details of the process.

The paper is from the User Interface & Software (UIST) conference in 2022, so the examples it uses are older: it discusses a canvas and handbag. The dress uses the same technology, though, draped over a scientist rather than a frame. If you can’t access the version from UIST, [Dierk] has a free version here.

The dress uses Polymer-dispersed Liquid Crystal (PDLC) panels from the wonderfully named Shanghai HO HO Industry Co and is designed for use in windows and doors for privacy. It uses an Indium Tin oxide-coated PET film that is opaque by default but becomes transparent when a voltage difference is applied across the material.

These panels are shaped to a hexagonal shape, then wired together with flexible PCBs in a daisy chain. Interestingly, [Dierk] found that the smaller the panels were made, the lower the voltage was required to trigger them. For their canvas example, they dropped the voltage to a much safer -15V to 15V levels to trigger the two states, which is much safer for a wearable device.

The panels are also not completely transparent when triggered: the paper describes them as having a “soft ivory” look when they are overlaying a reflective material. Greyscales can also be made using Pulse Coded Modulation (PCM) to vary the panel’s transparency. Driving the panels at 3.2KHz, they created 64 shades of grey.

The main controller is a custom PCB with a Teensy 4.1 and a BlueFruit LE SPI module. The power comes from two 14.8V LiPo batteries, with converters to power the chips and switch modules so the Teensy can switch the -15 and +15V levels for the panels directly from each battery.

The array is made from modules, each with four panels connected to a controller PCB, which has several Analog Signal Device (ASD) ADG1414 chips. These receive the signals from the bus with switch registers to switch the panels individually.

Rather cleverly, [Dierk] uses the bus that daisy chains the modules together to deliver both power and the bus signal that controls the panels, using the -15 and +15V levels modulated with a 50Hz square wave to create the bus signal and power the panels at the same time. That’s a neat hack that reduces the complexity of the modules significantly.

The Teensy 4.1 controls the whole system and can use its IMU to sense movement and change the pattern accordingly. You don’t get to see the system’s electronics in the dress video, but they claim that the canvas example took just 0.58 Watts to drive, so the dress probably only needs a few watts.

It is a fascinating build (and a rather cute dress), and has a lot of potential. What would you do with this?

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Cheap LCD Uses USB Serial

September 11, 2023 by 19 Comments

Browsing the Asian marketplaces online is always an experience. Sometimes, you see things at ridiculously low prices. Other times, you see things and wonder who is buying them and why — a shrimp pillow? But sometimes, you see something that probably could have a more useful purpose than the proposed use case.

That’s the case with the glut of “smart displays” you can find at very low prices. Ostensibly, these are being sold as system monitors. A business-card-sized LCD hooks up via USB and shows your CPU speed, temperature, and so on. Of course, this requires sketchy Windows software. I don’t run Windows, and if I did, I wouldn’t be keen to put some strange service on just so I could see tiny displays of my system information. But a 3.5-inch IPS LCD screen for $15 or less probably has some other uses. But how to drive it? Turns out, it is easier than you think and the hardware looks reasonably hackable, too.

Like a lot of this cheap stuff, these screens are sold under a variety of names, and apparently, there are some subtle differences. Two of the main makers of these screens are Turing and XuanFang, although you rarely see those names in the online listings. As you might expect, though, someone has reverse-engineered the protocol, and there is Python software that will replace the stock Windows software the devices use. Even better, there is an example of using the library for your own purposes.

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Raspi-Powered Typewriter Is A Real MUSE

September 5, 2023 by 4 Comments

Thanks to parenting and life in general, [Brendan] had fallen out of the habit of writing and wasn’t happy about it. If you write anything ever, you already know there are endless distractions when it comes to doing so on a computer. Sure, there always typewriters, but it’s difficult to do anything with the fruits of a typewriter other than scan it in or make copies, and it’s basically un-editable except by hand.

Instead of just sitting down and writing, [Brendan] did what any of us would do — took the time to create an elegant solution. The Most Unusual Sentence Extractor, or MUSE, is a Raspberry Pi-based typewriter with the best of both worlds. It’s essentially a word processor, but it can save to the cloud.

[Brendan] found beautiful inspiration in the Olympia Traveller de Luxe typewriter, a delightfully boxy affair made in the 1960s and 70s with lovely keys. Starting with a 68Keys.io board, [Brendan] set about re-creating the lines of the Traveller de Luxe in Tinkercad.

Since it doesn’t really need a platen, this was the perfect place to mount a screen using black PVC. At first, [Brendan] was going to use an e-ink screen, but a mishap led to a better solution — an LCD touchscreen that makes document navigation a breeze.

We absolutely love the look of this machine, which was obviously a labor of love. And yeah, it does the trick:[Brendan] is writing again. Though it maybe be inconvenient, we agree that it really is nice to have a dedicated workstation for certain things.

Looking for the complete opposite of this project? How about a Chat GPT-assisted daisywheel typewriter?

Tiny Spheres Hiding In Your Display

August 20, 2023 by 6 Comments

Liquid crystal and Organic LED displays have revolutionized portable computing. They’re also made of glass. Which presents a problem: How do we get electrical signals from fiberglass circuit boards to the glass displays? The answer is double-sided adhesive tape. But we’re not talking about packing tape here. As [Breakingtaps] explains,  this tape has a trick up its sleeve.

The magic is that the tape conducts only in the vertical plane. Even more so, any two conducting sections of the tape are insulated from each other. How does it do that? Magic beans balls, of course!

The tape and adhesive are insulators. Embedded in the adhesive are tiny spheres. The spheres are made of plastic and coated with metal. When the tape (also known as ACF or Anisotropic Conductive Film) is pressed between a PCB with conductors and glass, a few spheres are squished down between the layers. Electrical signals pass between the squished spheres, allowing an image to be displayed on the glass screen. The final step uses heat and pressure to bond the adhesive and cure it. You can also get the material in paste form if you don’t like the tape.

The system works so well that it can be used for connections from a silicon chip directly to the glass.  This is how many display controllers are mounted right to the module — definitely an improvement on the rubber strips used on LCDs of the past.

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A Look At Sega’s 8-Bit 3D Glasses

April 19, 2023 by 6 Comments

From around 2012 onwards, there was a 3D viewing and VR renaissance in the entertainment industry. That hardware has grown in popularity, even if it’s not yet mainstream. However, 3D tech goes back much further, as [Nicole] shows us with a look at Sega’s ancient 8-bit 3D glasses [via Adafruit].

[Nicole]’s pair of Sega shutter glasses are battered and bruised, but she notes more modern versions are available using the same basic idea. The technology is based on liquid-crystal shutters, one for each eye. By showing the left and right eyes different images, it’s possible to create a 3D-vision effect even with very limited display hardware.

The glasses can be plugged directly into a Japanese Sega Master System, which hails from the mid-1980s. It sends out AC signals to trigger the liquid-crystal shutters via a humble 3.5mm TRS jack. Games like Space Harrier 3D, which were written to use the glasses, effectively run at a half-speed refresh rate. This is because of the 60 Hz NTSC or 50 Hz PAL screen refresh rate is split in half to serve each eye.  Unfortunately, though, the glasses don’t work on modern LCD screens, as their inherent display lag throws off the timing of the pulses the console sends to the glasses.

It’s a neat look at an ancient bit of display tech that had a small resurgence with 3DTVs in the 2010s. By and large, it seems like humans just aren’t that into 3D, at least beneath a full-VR experience. Meanwhile, if you’re wondering what 8-bit 3D looked like, we’ve got a 3D video (!) after the break.

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Spice Up The Humble 16×2 LCD With Big Digits

April 7, 2023 by 16 Comments

The 16×2 LCD display is a classic in the microcontroller world, and for good reason. Add a couple of wires, download a library, mash out a few lines of code, and your project has a user interface. A utilitarian and somewhat boring UI, though, and one that can be hard to read at a distance. So why not spice it up with these large-type custom fonts?

As [upir] explains, the trick to getting large fonts on a display that’s normally limited to two rows of 16 characters each lies in the eight custom characters the display allows to be added to its preprogrammed character set. These can store carefully crafted patterns that can then be assembled to make reasonable facsimiles of the ten numerals. Each custom pattern forms one-quarter of the finished numeral, which spans what would normally be a two-by-two character matrix on the display. Yes, there’s a one-pixel wide blank space running horizontally and vertically through each big character, but it’s not that distracting.

Composing the custom patterns, and making sure they’re usable across multiple characters, is the real hack here, and [upir] put a lot of work into that. He started out in Illustrator, but quickly switched to a spreadsheet because it allowed him to easily generate the correct binary numbers to pass to the display for each pattern. It seems to have really let his creative juices flow, too — he came up with 24 different fonts! Our favorite is the one he calls “Tron,” which looks a bit like the magnetic character recognition font on the bottom of bank checks. Everyone remembers checks, right?

Hats off to [upir] for a creative and fun way to spice up the humble 16×2 display. We’d love to see someone pick this up and try a complete alphanumeric character set, although that might be a tall order with only eight custom characters to work with. Then again, if Bad Apple on a 16×2 is possible…

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