PaPiRus ePaper Hats
We have been having a bit of a play with the new PaPiRus ePaper HATs from Pi Supply. These are basically small displays (they come in different sizes; 1.44″, 2.0″ and 2.7″) which use ePaper technology and sit on the Raspberry Pi GPIO header. The great advantage of the ePaper (aka eInk) technology is that you can display information on the screen indefinitely; even after the power is switched off.
The PaPiRus Range
There is a range of different PaPiRus HATs available:
The PaPiRus HATs come as a kit but are really simple to put together. There is a PCB which contains all the circuitry required to drive the display, and this PCB also includes a Real Time Clock that is powered by a small coin cell, which comes with the kit. The ePaper display connects to the PCB by means of a short ribbon cable, and can then be stuck to the PCB by means of some double sided sticky pads (supplied). There is also the option of soldering 4 push buttons (also supplied) on to the PCB to allow a degree of control through the Raspberry Pi GPIO.
Once the PaPiRus HAT has been put together, it can then be mounted on the Raspberry Pi by slotting it onto the GPIO header, and there are nylon standoffs and screws supplied to allow you to secure the HAT to the Pi. Note, that if you are using the 2.7″ display, it’s a good idea to screw the standoffs on to the PCB before sticking the ePaper screen to the PCB; as once the screen is stuck to the PCB, you cannot access the holes for the screws at the top of the screen, as you can see from the picture below. This does not appear to be a problem with the smaller screens though.
Getting It Working
Although we really like this product, there does seem to be a bit of a shortage of information regarding construction and use of the HAT. A card that came with the HAT says that assembly guides, code examples, etc. can be found at the supplier Web site:
However, when we looked, we really struggled to find any useful information about the PaPiRus HATs.
We did manage to find some example code and libraries at the Pi Supply GitHub page:
However, we experienced a number of issues when trying to use this code.
Luckily, one of the issues that were raised on the PaPiRus GitHub page contained a link to an extremely useful document that highlighted all the issues that we had experienced, and solutions to these issues; and following the steps on Frederick’s document (see the link below), we eventually managed to successfully get our PaPiRus HAT working.