Startup Percheron Electronics Ltd is looking to fund their rather neat E-Paper display HAT for the Raspberry Pi. Unlike some similar display solutions for the Pi this E-ink HAT attaches without any long ribbon cables. An advantage of this type of display (similar to those used on the Kindle) is that the image persists on the screen when power is removed so they use less power than a TFT display but the E-Paper technology does not support fast moving images.
The PCB is compliant with 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 is also suitable for 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 within 3 minutes per year. The RTC can generate an interrupt/alarm signal and also a 32 KHz clock signal which can be connected through to GPIO pins by solder pad links, if required.
Software to drive the display is available from the Repaper GitHub repository comprising a low level C driver which interfaces to a host of Python demo programs which you can hack to your heart's content. It is possible to draw a completely new image to the panel or to partially redraw sections of the display, using functions from the Python Imaging Library (Pillow) and text can be placed using a variety of system fonts in various sizes.
With 24 days of the campaign still to run the £10,500 goal has already been exceeded.