Engineer tweaks e-paper screen to get higher refresh rate

American engineer and designer Bren Krasnow has put a video online in which he shows how he tweaks an e-paper screen purchased on AliExpress to achieve a higher refresh rate. In passing, he also explains how an e-paper screen actually works.

With the trick, he lets the screen refresh itself in 0.3 seconds, while that normally takes a few seconds. In addition, he managed to update only parts of the screen with custom firmware, while that is not possible with the standard firmware.

To do that, he modifies the code that controls how high the voltage is across the screen, how often that happens, and how long it lasts. By doing that, it is possible to send the positive or negative particles to the surface of the screen to show black or white.

Krasnow, who has a daily job at Google sister company Verily, has put the code of the modified firmware online so that users can get started themselves. The engineer uses a 4.2″ e-paper screen for his demonstration. E-paper is used in e-readers and some Sony watches, but the low refresh rate makes them unsuitable for other consumer electronics. Pebble wanted initially used e-paper for its smartwatches, but later opted for memory LCD, a variant of a regular LCD screen that consumes little power if the screen continues to show the same image.