One of the entries in the Hackaday Coin-Cell Challenge piqued my interest, initially because it featured an ESP, but then because of the beautiful display. The project goes by the name of “Badgy” and is basically just another WiFi enabled, conference-style badge. I was surprised that it used an ESP8266, because the whole point of the Coin-Cell Challenge was to eke out the maximum amount of life from a coin cell battery …and the ESP8266 is certainly not known for it’s low power consumption. As it turns out, the project’s creator, W4ilun, gives a whopping 35-day run-time for the device …but only when it’s in deep-sleep mode; with “normal” use that figure tumbles to around 21-hours (Ouch!).
Still, the thing that hooked me about the project was the beautiful display. Checkout W4ilun’s Hackaday.io gallery pages to see more examples of this stunning little e-Paper module.
The two things which have put me off these displays in the past are the complicated interface/support requirements and the prices. This little module seems to have (almost!) nailed those two drawbacks. The price is very competitive with current OLED modules (once you manage to find the supplier, anyway) and the weird voltage requirements which e-Paper displays have, is mostly handled on-module by the device itself, apart from a requirement for a simple, MOSFET boost circuit to generate the positive and negative gate drive voltages (this is driven from the display module, but the user needs to implement the circuit discretely …and no, I don’t know why it isn’t included on the display module, either. See page 50 of the manufacturer’s data sheet if you’re interested). The down side on the interface side is that it has a super-tiny 24-pin connector which your average, ageing through-hole-component constructor (with shaky hands) just isn’t going to be able to hack (so, even though W4ilun is offering the bare boards on Tindie, I’d like to suggest that he also sells a board-plus-display option, too).
If it wasn’t for that horrible connector, I would have ordered a couple of these displays already. As it is, I’ll be waiting for someone to produce an old-git-friendly version (preferably for about $8, including worldwide postage 😉 ).
Anyway, many thanks to W4ilun for all of the work he’s put in on this project and many congratulations to him on getting into the winner’s circle on Hackaday.