I recently researched USB connected information displays but I am interested in e-Ink. I want
- USB power + data
- Open interface so I can drive it from my own software on the host (but not like a traditional monitor, I imagine more uploading pre-rendered bitmaps)
- Image retention when powered off
- High resolution paper like appearance
- Between A5 and A4 in size
- At least black, red and yellow as colors
- Buttons or a way to connect buttons would be a bonus
Why is that expensive ? I’m genuinely asking. Considering the time / labor / troubleshooting etc to put something like this together yourself , plus cost of materials ?
In my mind , the labor rate for a professional is a minimum of 1.00 per minute. This package would be essentially one hour of billable time at the (lowest) rate a professional would bill themselves out at.
Presuming it’s FLO or at least some kind of simple AT command set and meets all the other requirements, I’m really struggling to understand how it’s expensive ?
I mean , sure if you need 10k of them or something.
The ones linked are nowhere near A4 or A5 in size. They didn't bother to even look up and suggested you realistic options. A4 sized e Ink panels at sample prices are, idk, $2k? Most engineers would be relatively price sensitive in those ranges.
It's not rare these days for people outside Asia to have completely broken mental math of engineering man-hours required for a product or how extremely subsidized the products in their hands are. iPhones can be bought for $499 not because they've figured out AI design and robotic mass production over in China, it's because they're leaving $2k-4k per unit on the table to be blown away in wind. And ultimately it's because that money is only nicety to them, not vital.
Which means, if you do the labor on your soil, your local economy will demand that amount to be on table plus some, counted, bound, and placed under a weight.
Color is the hardest thing on your list. I think something that meets most other requirements is the Inkplate 10, which I’ve been using as an apartment status display for a few years now. It’s ESP32 based and I have it grabbing an image from Home Assistant every minute, which it works great for. Black and white only though.
So a few years ago I hacked up this sort of thing.
I bought a generic epaper display from aliexpress, a 5.8 inch 648x480 one that could do white/black/red with an SPI interface, then I wired that to an RP2040 board, then wrote a bit of circuitpython firmware for that which could receive commands over USB and draw stuff on the display.
I got as far as being able to send images to it, and writing a little host program on my PC that would do a partial screen update on a clock display and CPU/GPU temperatures once a minute, and draw a Mandelbrot set in the remaining space, with a full screen refresh every 15 minutes because it needed it, and a several minute “exercise” routine that would take every pixel from white to black to red and back to white at midnight, to improve screen appearance longer term.
And then I got bored/annoyed with it as the refresh was so slow (~30s for a red update) and the rp2040 needed me to manually press its reset button after every windows boot or the usb device wasn’t recognised. I thought about rewriting the firmware in C in case it was circuitpython that was flakey … but lost the impetus.
- USB power + data
- Open interface so I can drive it from my own software on the host (but not like a traditional monitor, I imagine more uploading pre-rendered bitmaps)
- Image retention when powered off
- High resolution paper like appearance
- Between A5 and A4 in size
- At least black, red and yellow as colors
- Buttons or a way to connect buttons would be a bonus
If anyone has a tip, I'd be grateful.