eink

39 Articles

Better Air Quality Sensing With CO2

November 21, 2022 by 19 Comments

Measuring air quality, as anyone who has tried to tackle this problem can attest, is not as straightforward as it might seem. Even once the nebulous term “quality” is defined, most sensors use something as a proxy for overall air health. One common method is to use volatile organic compounds (VOCs) as this proxy but as [Larry Bank] found out, using these inside a home with a functional kitchen leads to a lot of inaccurate readings. In the search for a more reliable sensor, he built this project which uses CO2 to help gauge air quality.

Most of the reason that CO2 sensors aren’t used as air quality sensors is cost. They are much more expensive than VOC sensors, but [Larry] recently found one that was more affordable and decided to build this project around it. The prototype used an Arduino communicating over I2C to the sensor and an OLED screen, which he eventually put in a 3D printed case to carry around to sample CO2 concentration in various real-world locations. The final project uses a clever way of interfacing with the e-paper display that we featured earlier.

While CO2 concentration doesn’t tell the full story of air quality in a specific place, it does play a major role. [Larry] found concentrations as high as 3000 ppm in his home, which can cause a drop in cognitive function. He’s made some lifestyle changes as a result which he reports has had a beneficial impact. For human-occupied indoor spaces, CO2 can easily be the main contributor to poor air quality, and we’ve seen at least one other project to address this concern directly.

Liberated E-Ink Shelf Labels Turned 10×2 Display

August 4, 2022 by 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.

A Tshwatch on a table

TshWatch Helps You Learn More About Yourself

April 3, 2022 by 13 Comments

TshWatch is a project by [Ivan / @pikot] that he’s been working on for the past two years. [Ivan] explains that he aims to create a tool meant to help you understand your body’s state. Noticing when you’re stressed, when you haven’t moved for too long, when your body’s temperature is elevated compared to average values – and later, processing patterns in yourself that you might not be consciously aware of. These are far-reaching goals that commercial products only strive towards.

At a glance it might look like a fitness tracker-like watch, but it’s a sensor-packed logging and measurement wearable – with a beautiful E-Ink screen and a nice orange wristband, equipped with the specific features he needs, capturing the data he’d like to have captured and sending it to a server he owns, and teaching him a whole new world of hardware – the lessons that he shares with us. He takes us through the design process over these two years – now on the fifth revision, with first three revisions breadboarded, the fourth getting its own PCBs and E-Ink along with a, and the fifth now in the works, having received some CAD assistance for battery placement planning. At our request, he has shared some pictures of the recent PCBs, too!

Continue reading “TshWatch Helps You Learn More About Yourself” →

Wearable colour eink display in watch format showing additional internal details

Bendable Colour EPaper Display Has Touch Input Too

October 12, 2021 by 8 Comments

The Interactive Media Lab at Dresden Technical University has been busy working on ideas for user interfaces with wearable electronics, and presents a nice project, that any of us could reproduce, to create your very own wearable colour epaper display device. They even figured out a tidy way to add touch input as well. By sticking three linear resistive touch strips, which are effectively touch potentiometers, to a backing sheet and placing the latter directly behind the Plastic Logic Legio 2.1″ flexible electrophoretic display (EPD), a rudimentary touch interface was created. It does look like it needs a fair bit of force to be applied to the display, to be detectable at the touch strips, but it should be able to take it.

The rest of the hardware is standard fayre, using an off-the-shelf board to drive the EPD, and an Adafruit Feather nRF52840 Sense board for the application and Bluetooth functionality. The casing is 3D printed (naturally) and everything can be built from items many of us have lying around. The video below shows a few possible applications, including interestingly using the display as part of the strap for another wearable. Here is also is a report on adding interactive displays to smart watches. After all, you can’t have too many displays.

Many wearables projects can be found in the HaD archives, including this dubious wearable scope, a method for weaving OLED fibres into garments. Finally, for a good introduction to wearable DIY tech, you could do worse than this Supercon talk from Sophy Wong.

Continue reading “Bendable Colour EPaper Display Has Touch Input Too” →

Take Note: An E-Paper Tablet From Pine64

August 17, 2021 by 20 Comments

Over the years we’ve seen a variety of interesting pieces of hardware emerging from the folks at Pine64, so it’s always worth a second look when they announce a new product. This time it’s the PineNote, a tablet that packs the same Rockchip RK3566 as used in the company’s Quartz64 single board computers behind a 10.1″ 1404 x 1872 16-tone greyscale e-paper screen.

Fitted with 4 GB of LPDDR4 RAM and 128 GB eMMC flash storage, it will feature the same Linux support as previous Pine64 products, with the slight snag of the display driver not yet being complete for 5.xx kernels. They are thus at pains to point out that this is not a ready-to-go consumer device and that early adopters will be expected to write code rather than notes on it.

That last sentence sums up Pine64’s offering perfectly, they produce interesting hardware with open-source support, but sometimes the path from hardware release to stable and usable product can be a rocky one. If you’re interested in hardcore hacking of an e-paper tablet, then you may want to be an early adopter. Otherwise, hang back for a while and buy one once some of the bugs have been ironed out. Meanwhile you can see the whole update in the video below; it has a few other things including a nifty keyboard for the PinePhone.

We’ve mentioned Pine64 a few times over the years, it’s worth noting that their products also lie outside the realm of Linux boxen.

Continue reading “Take Note: An E-Paper Tablet From Pine64” →

A Fresh E-Ink Newspaper Delivered Every Morning

April 11, 2021 by 28 Comments

[Greg Raiz] recently set out to make it easy to read multiple newspapers in the morning over breakfast. Inspired by a similar project, he built an e-ink newspaper that hangs on his wall, delivering fresh news every ten minutes.

The project started with a 32″ Visionect e-ink display configured as a thin client. With a battery life measured in months thanks to the low power electronics, most of the work here was focused on the backend. A docker container running on a local NAS server collects newspapers via freedomforum.org, formats them to fit the aspect ratio of the display, and serves them up. [Greg] is really trying to preserve the design and thought that goes into the front page of each of these publications as traditional newspaper layouts are often designed by hand.

We love the simplicity and the “it-just-works” feel of this project as there are no buttons, wires, or anything that you need to fiddle with. [Greg] points out that it could also be used for other purposes, and we’d love to see a large calendar such as this e-ink calendar or perhaps even a 32″ version of this e-ink laptop. The code for this is on his GitHub with a video after the break.

Continue reading “A Fresh E-Ink Newspaper Delivered Every Morning” →

A Deep Dive Into E-Ink Tag Hacking

March 28, 2021 by 7 Comments

Over the last decade or so, e-ink price tags have become more and more ubiquitous, and they’ve now reached the point where surplus devices can be found inexpensively on various websites. [Dmitry Grinberg] found a few of these at bargain-basement prices and decided to reverse engineer and hack them into monochrome digital picture frames.

Often, the most difficult thing about repurposing surplus hardware is the potential lack of documentation. In the two tags [Dmitry] hacked, not only are the labels not documented at all, one even has an almost-undocumented SoC controlling it. After some poking around and some guesswork, he was able to find connections for both a UART and an SWD debugging interface. Fortunately, the manufacturers left the firmware unprotected, so dumping it was trivial.

Even with the firmware dumped, code for controlling peripherals (especially wireless devices) is often inscrutable. [Dmitry] overcomes this with a technique he calls “Librarification” in which he turns the manufacturer’s firmware into libraries for his custom code. Once he was able to implement his custom firmware, [Dmitry] developed his own code to wirelessly download and display both gray-scale and two-color images.

Even if you’re not interested in hacking e-ink tags, this is an incredible walk-through of how to approach reverse-engineering an embedded or IoT device. By hacking two different tags with completely different designs, [Dmitry] shows how to get into these systems with intuition, guesswork, and some sheer persistence.

If you’d like to see some more of [Dmitry]’s excellent reverse-engineering work, take a look at his reverse-engineering and ROM dump of the PokeWalker. If you’re interested in seeing what else e-ink tags can be made to do, take a look at this weather station made from the same 7.4″ e-ink tag.