Driving E-Paper Displays With Memory Limited MCUs

November 21, 2022 by Tom Nardi 20 Comments

It’s easy to become jaded by modern microcontrollers: for just a few bucks you can get a MCU that’s powerful enough to give a desktop computer from the early 90s a run for its money while packing in contemporary technology like WiFi and Bluetooth. For many projects we don’t even have to consider optimizing our code, because we aren’t even scratching the surface of what the hardware is capable of.

But sometimes you don’t have the luxury of using the latest-and-greatest chip, and have to play the hand you’re dealt. That’s when folks like [Larry Bank] really shine. In a recent write-up, he goes over his experiments with driving e-paper displays (specifically, salvaged electronic shelf labels) with 8-bit MCUs that on paper shouldn’t have the resources to run them.

The problem is that these displays generally expect to be handed a fully-formed image, which can easily exceed the free RAM on a low-end chip. For example, a 1-bit 128 x 128 image would consume 2 KB of RAM — more than four times the available memory on an ATtiny85.

As [Larry] explains, his alternate approach is to write data to the display in columns that are only one byte wide. Combined with his existing work with image decompression on constrained hardware, he’s able to rapidly draw out full-screen TIFF images using an Arduino UNO as demonstrated in the video after the break. He hopes the work will inspire others to experiment with what’s possible using the dinky MCUs you generally find in second-hand shelf labels.

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Cyberdeck Contest 2022: Gibson Rev 001 Thinks Outside The Pelican Case

October 25, 2022 by Kristina Panos 5 Comments

As we’ve gushed previously in these pages, we saw an incredible turnout for our first-ever cyberdeck contest — so many cool ‘decks rolled in that it made judging them all quite the feat, and we would be remiss if we didn’t feature the favorites that, for whatever reason, didn’t make the cut. One of these is the aptly-named Gibson Rev 001 from [Gadjet].

This cyberdeck may be on the pocket-sized side of things, but don’t let that fool you, because it’s loaded with I/O and sensors galore. A Pimoroni Breakout Garden provides particle/smoke and pulse oximetry, temperature/pressure/altitude, an air quality sensor, and a UVA/UVB light sensor — plenty of feelers for judging conditions on the fly. As you might expect, the brains of the operation is a Raspi 4, which is running Twister OS.

We love the dual-display thing going on with the 7″ touchscreen and the color e-ink display — really gives it a cobbled-together-yet-polished, futuristic feel. May the rest of the post-apocalypse gadgetry have such clean lines and cheerful colors (if that’s what you’re into).

Macintosh Classic II With E-Ink Display

August 24, 2022 by Bryan Cockfield 30 Comments

As various antique computers age, it becomes increasingly hard to operate them as hardware begins to physically fail. Keeping these systems up and running often requires scavenging parts from other machines which are only becoming harder to find as time goes on. But if you throw out the requirement of using only era-appropriate components, there are some interesting ways to revive older devices with a few touches of modern tech, like this Mac Classic with a unique display.

The Macintosh Classic II was the successor to the first Macintosh computer Apple sold that had a price tag under $1000. As such, there were some lower specs for this machine such as the monochrome 512×342 display. This one has been retrofitted with an e-ink display which actually gives it some of the same grayscale aesthetic as the original. The e-ink display is driven by a Raspberry Pi which displays a replica System 7 environment and a set of photos.

While the only part of the computer that’s original is the shell at this point, the project’s creator [Dave] also built in support for the Apple Desktop Bus through an Arduino so the original Apple mouse and keyboard can be used. While it’s largely an illusion of a working Mac Classic, we still appreciate the aesthetic.

If you’re more of a classic Apple purist, though, take a look at this SE/30 which uses almost entirely original parts with the exception of a Raspberry Pi to allow it to communicate with the modern Internet.

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Every Frame A Work Of Art With This Color Ultra-Slow Movie Player

August 19, 2022 by Dan Maloney 15 Comments

One of the more recent trendy builds we’ve seen is the slow-motion movie player. We love them — displaying one frame for a couple of hours to perhaps a full day is like an ever-changing, slowly morphing work of art. Given that most of them use monochrome e-paper displays, they’re especially suited for old black-and-white films, which somehow makes them even more classy and artsy.

But not every film works on a monochrome display. That’s where this full-color ultra-slow motion movie player by [likeablob] shines. OK, full color might be pushing it a bit; the build centers around a 5.65″ seven-color EPD module. But from what we can see, the display does a pretty good job at rendering frames from films like Spirited Away and The Matrix. Of course there is the problem of the long refresh time of the display, which can be more than 30 seconds, but with a frame rate of one every two hours, that’s not a huge problem. Power management, however, can be an issue, but [likeablob] leveraged the low-power co-processor on an ESP32 to handle the refresh tasks. The result is an estimated full year of battery life for the display.

We’ve seen that same Waveshare display used in a similar player before, and while some will no doubt object to the muted color rendering, we think it could work well with a lot of movies. And we still love the monochrome players we’ve seen, too.

Liberated E-Ink Shelf Labels Turned 10×2 Display

August 4, 2022 by Al Williams 27 Comments

How expensive is it to make a panel that uses e-ink technology? That might depend on how flexible you are. [RBarron] read about reverse engineering point-of-sale shelf labels and found them on eBay for just over a buck apiece. Next thing you know, 20 of them were working together in a single panel.

The panels use RF or NFC programming, normally, but have the capability to use BLE. Naturally you could just address each one in turn, but that isn’t very efficient. The approach here is to use one label as a BLE controller and it then drives the other displays in a serial daisy chain, where each label’s receive pin is set to the previous label’s transmit pin.

That allows a simple piece of code to read incoming messages and process the ones addressed to that label. Anything else just gets sent out the serial port. Only the BLE node has special firmware. At first, we thought each label would need an address and we wondered how it would be set other than having unique firmware for each one since there doesn’t appear to be a handy way to do a hardware-based configuration.

The actual solution is clever. Each message has a hop counter that each node decrements before passing the message along the chain. When the hop count is zero, the message is at its destination. Simple and very easy to configure. In theory, you could replace any of the labels after the first one with any other label and the system would still work correctly.

Even the wiring is clever, with a jig to bend the wire to ensure even spacing of each element on the panel. A laser-cut box finishes the project off nicely. The code is all available on GitHub. We’ve seen these kinds of tags used for things like weather stations. Not to mention conference badges.

Hackaday Links: June 19, 2022

June 19, 2022 by Dan Maloney 11 Comments

The James Webb Space Telescope has had a long and sometimes painful journey from its earliest conception to its ultimate arrival at Lagrange point L2 and subsequent commissioning. Except for the buttery-smooth launch and deployment sequence, things rarely went well for the telescope, which suffered just about every imaginable bureaucratic, scientific, and engineering indignity during its development. But now it’s time to see what this thing can do — almost. NASA has announced that July 12 will be “Image Release Day,” which will serve as Webb’s public debut. The relative radio silence from NASA on Webb since the mirror alignment was completed — apart from the recent micrometeoroid collision, of course — suggests the space agency has been busy with “first light” projects. So there’s good reason to hope that the first released images from Webb will be pretty spectacular. The images will drop at 10:30 AM EDT, so mark your calendars and prepare to be wowed. Hopefully.

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A wooden picture frame with an e-ink display

Receive Virtual Postcards On This Beautiful E-Ink Photo Frame

May 22, 2022 by Robin Kearey 12 Comments

Sending postcards to loved ones used to be standard procedure for travelers back when travel was glamorous and communications were slow. While some travelers still keep this tradition alive, many have replaced stamps and post offices with instant messaging and social media — faster and more convenient, but a lot less special than receiving a postcard with a handwritten message from a faraway land.

[Cameron] designed a postcard picture frame that aims to bring back a bit of that magic. It’s a wooden frame that holds an e-ink display, which shows pictures sent to it by your friends. All they need to do is open the unique link that you sent them beforehand and upload an interesting photo; the picture frame will cycle through the submissions based on an adjustable schedule. A web interface allows you to change settings and delete any inappropriate images.

The wooden frame is beautifully made, but the sleek black PCB inside is an true work of art. It holds a battery and a USB-C charging circuit, as well as an ESP32 that connects to WiFi, stores images and downscales them to the 800×480 monochrome format used by the display. [Cameron] has not accurately measured the current consumption, but estimates that it should work for about one year on a single charge thanks to the extremely low power requirements of e-ink displays.

Having your friends decide on the images shown in your house is an interesting idea, if you can trust them to keep it decent. If you like to have more control over your e-ink display, have a look at this solar-powered model or this wall-mounted newspaper display.

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