NiceThings' Inkster Drives ePaper Displays with an ESP32 — and Boasts a Few Bonus Features, Too
Designed to drive larger ePaper displays, the Inkster includes battery charging support, three optional buttons, and an RGB LED.
Czechia-based NiceThings has launched an ESP32-based driver board for ePaper displays, based on the EPDiy project but with some handy tweaks — including a more compact layout, three buttons, a thermistor, and a voltage divider for battery monitoring.
" I (arguably) helped design the V5 [EPdiy] board," NiceThings' founder Martin Černý explains, "and later made Inkster, which is my own flavor of the board with some tweaks. It is super compact and even though this board is universal, it's tailored for some displays in a way that they wrap around the board and make very compact projects possible."
Driven by an Espressif ESP32-WROVER-B module, the board supports 33- and 34-pin ePaper displays with up to 16 levels of gray, though its more compact design ditches the 39- and 40-pin connectors found on the EPDiy boards that inspired it. There are pads for up to three switches, a TP4056 charging circuit plus pads for a lithium-polymer battery, a voltage divider for battery monitoring, and a thermistor for temperature measurement.
A key selling point of the board is a low deep-sleep current of just 14µA — which, combined with the fact that ePaper displays retain whatever's on them even when power is completely removed, will allow for some long-lived projects. A micro-USB connector offers data and power connectivity, with a CH340 chip for serial communication. Finally, an RGB LED is included for status notifications.
"I wanted to make gift photo frames for Christmas for my family members," mcer12 writes. "The photo frames were supposed to download random image from remotely hosted photo library every day. I designed my own board and was able to do just that and the reactions from my family were overwhelming. But of course that’s one use case."
The work builds on a similar "universal" ePaper display driver released by NiceThings last year, which offered a compact footprint but lacked support for larger ePaper displays — and had no on-board microcontroller, making it unsuitable for standalone projects without a host board.
A schematic, bill of materials, and Gerbers for the board have been published to GitHub under the reciprocal GNU General Public License 3; boards are available to buy on the NiceThings Tindie store at $69. A 3D-printable case for the Inkster board and display in 6" or 9" variants is available on Thingiverse under the permissive Creative Commons Attribution license.