E-paper displays are unusual in that power is only needed during a screen update. Once the display’s contents have been set, no power whatsoever is required to maintain the image. That’s pretty nifty. By making the display driver board communicate wirelessly over near-field communication (NFC) — which also provides a small amount of power — it is possible for this device to be both wireless and without any power source of its own. In a way, the technology required to do this has existed for some time, but the company Waveshare Electronics has recently made easy to use options available for sale. I ordered one of their 2.9 inch battery-less NFC displays to see how it acts.
Waveshare, known for e-ink components aimed at hobbyists among other cool parts, has recently released a very interesting addition to their product line. This is an enclosed e-ink display which gets updated over a wireless NFC connection. By that description, nothing head-turning, but the kicker is that there is no battery inside the device at all, as it harvests the energy needed from the wireless communication itself.
Just like wireless induction charging in certain smartphones, the communication waves involved in NFC can generate a small current when passing through a coil, located on this device’s PCB. Since microcontrollers and e-ink displays consume a very small amount of current compared to other components such as a backlit LCD or OLED display, this harvested passive energy is enough to allow the display to update. And because e-paper requires no power at all to retain its image, once the connection is ended, no further battery backup is needed.
E-paper is notorious for having very low refresh rates when compared to more conventional screens, much more so when driven in this method, but there are ways to speed them up a bit. Nevertheless, even when used as designed, they’re perfectly suited for being used in clocks which are easy on the eyes without a glaring backlight.
The Logitech SqueezeBox was a device you hooked up to your stereo so you could stream music from a Network Attached Storage (NAS) box or your desktop computer over the network. That might not sound very exciting now, but when [Aaron Ciuffo] bought it back in 2006, it was a pretty big deal. The little gadget has been chugging all these years, but the cracks are starting to form. Before it finally heads to that great electronics recycling center in the sky, he’s decided to start work on its replacement.
Thanks to the Raspberry Pi, building a little device to stream digital audio from a NAS is easy these days. But a Pi hooked up to a USB speaker isn’t necessarily a great fit for the living room. [Aaron] didn’t necessarily want his replacement player to actually look like the SqueezeBox, but he wanted it to be presentable. While most of us probably would have tried to make something that looked like a traditional piece of audio gear, he took his design is a somewhat more homey direction.
An OpenSCAD render of the enclosure.
The Raspberry Pi 4 and HiFiBerry DAC+ Pro live inside of a wooden laser cut case that [Aaron] designed with OpenSCAD. We generally associate this tool with 3D printing, but here he’s exporting each individual panel as an SVG file so they can be cut out. We especially like that he took the time to add all of the internal components to the render so he could be sure everything fit before bringing the design into the corporeal world.
While the case was definitely a step in the right direction, [Aaron] wasn’t done yet. He added a WaveShare e-Paper 5.83″ display and mounted it in a picture frame. Software he’s written for the Raspberry Pi shows the album information and cover art on the display while the music is playing, and the current time and weather forecast when it’s idle. He’s written the software to plug into Logitech’s media player back-end to retain compatibility with the not-quite-dead-yet SqueezeBox, but we imagine the code could be adapted to whatever digital media scheme you’re using.
It’s hard to beat the fidelity and durability of printed text on paper. But the e-paper display gets pretty close, and if you couple it will great design and dependable features, you might just prefer an e-reader over a bookshelf full of paperbacks. What if the deal is sweetened by making it Open Hardware? The Open Book Project rises to that challenge and has just been named the winner of the Take Flight with Feather contest.
This e-reader will now find its way into the wild, with a small manufacturing run to be put into stock by Digi-Key who sponsored this contest. Let’s take a closer look at the Open Book, as well as the five other top entries.
Like many of us, [Zach Archer] enjoys the comfort of his darkened room so much that he has trouble getting up and facing the day. To make things a little easier for himself, he decided to put together a custom alarm clock that would fill his mornings with the glorious glow of LEDs; and since he finds the mountains an inspirational sight he decided to wrap the whole thing up in a 3D printed enclosure that resembles snow capped peaks.
But even Bob Ross himself couldn’t have imagined a snowy mountain range that featured an integrated e-ink screen. The big 4.2″ panel is connected to a custom designed PCB by [romkey], which was graciously donated for this project. An ESP32 runs the show, providing a convenient web interface to control not only the clock, but various aspects of the mountain’s internal LEDs such as fade in time and total duration.
[Zach] says he originally printed the mountains in PLA, but the heat generated by the LEDs eventually started to cause things to warp. Switching over to translucent PETG not only solved the heat problem, but made for a very effective LED diffuser. Rather than complex animation patterns, he’s found that smoothly transitioning between different shades of blue and green seems to work best for him in the mornings.
For a long time it seemed like e-ink displays were outside the reach of us lowly hackers, as beyond the handful of repurposed Kindles that graced these pages, we saw precious few projects utilizing this relatively exotic display. But that’s changed over the last couple of years, and we’re thrilled to start seeing hackers bend this incredible technology to their will.
A perfect example is PaperLedger, an entry into the 2019 Hackaday Prize by [AIFanatic]. This wireless device is designed to display the current price of various cryptocurrencies on its 2.9-inch e-ink screen and provide audible price alerts with its built-in speaker. It even has a web portal where users can configure the hardware or view more in-depth price information.
The PaperLedger is based on the TTGO T5 V2.2 ESP32, but it looks like [AIFanatic] is in the process of spinning up a new board for the MIT licensed project to address some nagging issues for this particular application. Unfortunately, it doesn’t look like there are any pictures of the new board yet, but a description of the changes on the Hackaday.IO page shows that most of the work seems to be going into improving support for running on batteries.
Even if you’re not interested in cryptocurrency, the PaperLedger looks like a fantastic little e-ink monitor for pretty much anything else you’d like to keep a close eye on. The GPLv3 licensed firmware is available on the project’s GitHub page, so expanding or completely changing the device’s functionality shouldn’t be too tricky for anyone with a desire to do so and a working knowledge of C++.
Most e-book readers don’t have physical page turn buttons. Why? They just don’t. Virtual page turns are accomplished with a tap at a screen edge. Determined to reduce the awkwardness of one-handed use, [Sagar Vaze] modified a Kobo e-reader with two physical page turn buttons as a weekend project.
[Sagar] points out that since the underlying OS of the Kobo device is Linux, it is possible to fake touches to the screen (and therefore trigger page turns) by recording then replaying the appropriate input event. However, there was a more direct solution available to those willing to tamper slightly with the hardware. Touch sensing on the screen is done via an infrared break-beam system. Along two edges of the screen are IR emitters, and opposite the emitters are receivers. Broadly speaking, when a fingertip touches the display a minimum of two IR beams are broken, and the physical location of the fingertip can therefore be determined by analyzing exactly how the IR pattern has been changed.
To spoof page turns, [Sagar] briefly shorts two IR emitters: one on each axis. The sudden winking out of the IR is interpreted by the device as a crisp tap, and the device obediently turns the page. The only hitch is that both IR emitters must be shorted at the same time. If one is shorted before the other, the device ignores it. Double-pole switches would probably do the trick, but with the part bin coming up empty in that respect, [Sagar] instead used a few transistors to accomplish the same thing. A 3D printed enclosure rounds out the whole mod, and a brief video is embedded below.
