from Hacker News

A WiFi color eInk picture frame

by thomasjb on 4/24/23, 4:24 PM with 85 comments

  • by SillyUsername on 4/24/23, 6:39 PM

    This is the same e-ink device I believe that's in the Pimoroni Inky Impression.

    I've written a Python program that anecdotally fixes the bias caused by the display for blues and greens, and dithers using an Atkinson dither. The code is based on some older Java implementation I wrote, but if you are considering a port to C this is more succinct (entry point diffuse_image()):

    https://github.com/KodeMunkie/inky-impression-slideshow/blob...

    The fix is to define the ink's blue as a slightly different hue than the device specifications, which tends to over emphasise it - improving it - when it comes to shades like sky blue (which the display can't achieve). So instead of (perhaps) being quantised to green, which is closer colour match for the actual real hue, more blue is shown instead. Whilst this is incorrect for photographic colour accuracy, if you don't know what the original photo looks like it appears to be correct and better than the colour that is typically chosen (green).

  • by catapart on 4/24/23, 5:03 PM

    Wow! There's a dynamite product in here that pairs a daily nagging app and one of these displays so that people are reminded to take a new picture, ever day, and have it show up on someone's (or all subscribed) photo frame.

    I'm thinking, like, "take a photo of the kids so it will show up on Grandma's frame" kind of functionality. Though, obviously, it would also be used for porn, so there's a market there, too.

    Anyway, very good DIY proof of concept. I hope it's productized with some of the more recent E-Ink updates soon!

  • by notfried on 4/24/23, 5:09 PM

  • by alexose on 4/24/23, 5:11 PM

    I think the world of homebrow eInk devices is set to take off.

    The problem right now is that while the screens have come down in price considerably, the driver hardware remains expensive and proprietary. If you want to build something for cheap, you'll be designing the PCB from scratch (as this author did).

    Enter EPDIY, which brings wide support to a variety of screens using commodity hardware. It's still under development, but it's looking really promising: https://github.com/vroland/epdiy

  • by sho_hn on 4/24/23, 5:10 PM

    I made something similar recently, albeit not in color:

    https://imgur.com/a/NoTr8XX / https://hackaday.io/project/190478-hyepaper

  • by layer8 on 4/24/23, 5:42 PM

    I wonder if we’ll ever see significant improvements in e-ink contrast, which is still very poor. There hasn’t been much progress over the last decade. I’d love to have laser-printer-level e-ink.

  • by fnordian_slip on 4/24/23, 5:00 PM

    I didn't even know there are decent e-ink colour displays available. I have to admit that I've been wanting to do something similar for a while, but I've always been too lazy to start, so kudos from me for that project!

    I love e-ink in general, it's a shame that it's still so rarely used. My fossil hybrid hr watch uses it, for example, but though the watch itself is incredible, the app is pure garbage. If that weren't the case, I'd recommend it to everyone.

    I wonder if there aren't a lot more cases like that, where it seems like costumers don't like the technology, even though they mainly resent the paired implementation of the big players who thought that the technology alone was enough of a selling point, and therefore neglected the software.

  • by crzysdrs on 4/24/23, 9:09 PM

    If anyone wants to make a similar project, there is a great Rust API to most of the Waveshare displays[0] (I added support for the display mentioned in the article, 5in65f).

    I also made a project[1] with it that generates art using a gameboy emulator and some static images and other transforms to show on the display.

    [0] https://github.com/caemor/epd-waveshare

    [1] https://github.com/crzysdrs/slate

  • by squarefoot on 4/24/23, 9:44 PM

    "... With only 7 colors and a refresh time of about a minute ..."

    Ouch, even worse than expected. The project is interesting, but I'm totally unimpressed by these numbers; I wouldn't pay a premium for a sub par display that is slow as a dead sloth. A traditional LED screen plus some tricks to save power would make a much better picture frame IMO. I would for example use a PIR/microwave sensor (they're cheap!) to detect when someone is approaching or stationing near the picture frame to bring the CPU back from sleep and turn on the display and backlight. It would never reach the same almost zero current draw of a epaper screen, but the quality gain paired with the lower cost would probably make it a viable alternative.

  • by jhoelzel on 4/24/23, 8:19 PM

    For a minute i had my hopes up there! I actually tried to build a wall of those and a motion activated picture wall for me and my fiance in order to have a wall of living memories.

    The problem i ran into is that you simply cant get them in decent sizes, or with a satisfying enough resolution.

  • by thih9 on 4/24/23, 5:05 PM

    Impressive DIY project.

    Still, as a person with no intention to DIY, I’m looking forward to a simple eink photo frame product.

    Crucially, something that works out of the box and is shipping now (so: no Kickstarter, no need to write custom scripts, etc).

  • by stavros on 4/24/23, 5:33 PM

    I made something similar with the LilyGo T5 the other day:

    https://www.stavros.io/posts/making-the-timeframe/

    You can probably adapt the code to drive this display, and it displays an image from a remote server, so all you need is an HTTP server and you can easily display whatever you want.

  • by anupmm on 4/24/23, 5:57 PM

    Hi Thomas - Really cool project and website. Just wanted to give you an unsolicited pat on the back to keep doing amazing things!!

  • by Waterluvian on 4/24/23, 10:38 PM

    Thousands of price tags at my local grocery stores use color eink screens like this. Not sure how colourful they are but they at least have red.

    It’s a neat idea. To be able to remotely set all tags once they’ve been properly localized.

  • by l8rlump on 4/26/23, 4:29 AM

    A small trick I learned from his power supply: using a P-channel MOSFET with the gate tied to ground for reverse-polarity protection. Presumably much less voltage drop than a diode.

  • by phkahler on 4/24/23, 6:27 PM

    Solar power? Could enough energy be stored from indoor light to power the daily download? That's about the only improvement I can think of.

  • by andai on 4/24/23, 6:13 PM

  • by sigmar on 4/24/23, 5:21 PM

    Would absolutely buy a product like this if it had maybe one or two more colors in the display

  • by tailspin2019 on 4/25/23, 3:05 PM

    That custom PCB is a labour of love… including repair instructions and spare parts!

  • by Takennickname on 4/24/23, 5:05 PM

    That title is nerd porn.

  • by squokko on 4/24/23, 5:30 PM

    Don't see the advantage of eInk for a digital photo frame. Presumably these stay in one spot and can be left plugged in? Would think that a bright LED display would give much better picture quality.