Hello John,

I’m so pleased to have found this project, having struggled to eliminate the current draw of Waveshare’s “e-paper Driver HAT” for a battery-powered project of mine.  Waveshare eventually confessed that their HAT continues to draw current even when the both the micro controller and the e-ink display are put to sleep.  Not much good for a long duration battery project.

Anyway, your schematic has helped me to unravel the problem far more easily, and I have now made a version of my own - eliminating all the voltage regulator circuitry as my project is running on a stabilised 3V3.

With only the elements essential to the e-ink display, the board is just 21 x 25mm.  It should suit any barebones ESP8266 or 3V3 Arduino project.

Thank you for your efforts, I’ll post any results or further thoughts here.

Hi,

How did you decide to use 0805 for the capacitors and CD43 for the inductor?

I'm grateful you have read through WavShare's documentation to decipher their schematic and posted your findings here.  They did publish a new rev in January and they now list C3 (between the diodes) as 4.7uF (IS 4.7 uF, WAS "104"), whereas you appear to be using 100 nF.  Do you have any thoughts on this?

https://www.waveshare.com/w/upload/5/5b/1.54inch_e-Paper_Schematic.pdf

It may be an error but here is waveshares older schematic (2018)

https://www.waveshare.com/w/upload/archive/5/5b/20200103064017%211.54inch_e-Paper_Schematic.pdf

I have tested it and the 100nF is what I have installed and it works.

 I haven't tested it with larger displays yet.