I have used E-Ink displays in projects three years ago, but from that time the technology has greatly evolved. That time displays were hard to get, expensive and difficult to use. Now things seem to change with e-ink displays available to the maker market :-). I’m able to get a 128×296 pixel e-paper display for $10! And for little more money I can have displays with black/white/red colors!
Wave share
When I have built the Squix WiFi weather station (see SQUIX ESP8266 based E-Paper WiFi Weather Station), I realized that this display is from Waveshare Electronics.
Wave share is a kind of reseller, and they do not seem to manufacture these displays. I have ordered 2.9″ display modules and breakout boards from DX.com (but they are available from many other sellers too).
On the bottom two displays with black/white as used in the weather station. The top two ones are interesting as they can display black, white and red. As seen on the right display, even a ‘grayscale’ or ‘red-scale’ is possible!
How it works
Ben Krasnov featured a very good video how these display work: basically a voltage is applied to the pixel cells, driving the color particles in a fluid either to move towards the front or back of the display. The video of Ben Krasnov explains this concept very well.
We have put the displays under a high-resolution microscope (thanks to Christian Di B. for introducing me to that equipment!), and it is possible to see the particles!
Black and White Displays
The images below are from the ‘black and white’ display:
Here a text written on the display. The character white lines are two pixels wide:
Detail of a 3×2 black pixel area:
Below the corner of a black pixel surrounded by white particles:
To give an idea of a pixel size and how many particles build it, here a row of black and white pixels:
The top of the display is covered with kind of anti-glare material. If you know the Kindle reader: this makes the surface very smooth and avoids reflections. Here an image zoomed above the pixels (one pixel lines) showing that it contains some kind of colored particles. I’m not exactly sure what they are.
Read More: Details of Waveshare e-paper displays