Ben E-paper
Ben E-paper is an experiment with the Ben NanoNote and an EM027AS012 display from Pervasive Displays, currently using an Embedded Artists' 2.7 inch E-paper Display module. Unlike the LCD screen on the Ben, current electronic paper displays have very slow refresh times and are typically monochrome, despite the emergence of colour e-paper technologies. However, they can retain the image indefinitely when powered off and are consequently finding use in high volume applications such as store shelf labelling, as well as in things like electronic book readers where the idea of electronic paper was perhaps most aggressively pursued.
[edit] Goals
- Experiment with SPI communication using the 8:10 port (see UBB)
- Evaluate e-paper as a display technology
- Consider applications of e-paper with embedded and mobile devices
[edit] Progress
Since the EM027AS012 and its siblings are supported with code and documentation, software has already been written for a variety of embedded systems. Here, the challenge was to evaluate and adapt such software for use with the Ben, given that systems like the Arduino, Raspberry Pi, mbed, and various other boards all have potentially different capabilities and APIs for communicating with attached devices. Initially, it appeared that driving the display from the Ben would be challenging due to an apparent need for more output pins than the 8:10 port on the Ben can provide. However, with power being supplied from a separate source, a scheme involving available pins was devised.
A repository is available containing code to allow the Ben to communicate with the display, and some results are shown below.
The display connected to breadboard power and the Ben via a cable and a Sparkfun microSD sniffer
A closer look at the display and cable
The display powered off and held by the Ben
The display is not much smaller than the Ben's LCD, but it has a somewhat lower resolution at 264 x 176 (versus 320 x 240 for the LCD)
