E-paper is a low power, high contrast display technology such as is used in the Kindle ® and other e-book readers. One of the really nice features is that the display panel keeps displaying whatever image was sent last, even when power is removed. I’ve always thought it would be rather cool to have such a display for the Raspberry Pi.
What is it? The E-Paper HAT
So I made a printed circuit board (PCB) which meets the Raspberry Pi Foundation’s HAT specification, including device tree configuration of the required GPIO pins by the HAT EEPROM.
The board is able to drive a 2.7″ 264 x 176 pixel E-paper display panel and I’m really rather pleased with the way it looks. It can also drive the 1.44″ and 2″ display panels from the same manufacturer.
The board also features a DS3231 real time clock (RTC) IC with a CR1220 lithium coin cell for battery backup when the Pi is powered down. The DS3231 is accurate to 5 parts per million, or to within 3 minutes per year. The RTC can generate an interrupt/alarm signal and also a 32KHz clock signal which can be connected through to GPIO pins by solder pad links, if required.
Favorite perk (£39)
One E-Paper HAT Display with battery backed Real Time Clock.