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Revision 2

A project log for paperd.ink

Low power e-paper dashboard using ESP32

Rohit GujarathiRohit Gujarathi 05/09/2021 at 11:480 Comments

The revision 2 PCBs are here! This revision contains quite a few changes to simplify manufacturing as well as lower the sleep current. These have a green solder mask but eventually will go for the original white one.

The front panel is removed since it was difficult to manufacture reliably and was adding a lot of cost. 4 tactile buttons have been added instead. 

The dependency on PCF8574 for controlling a few of the IOs is removed and is now only connected to the expansion header. So it's easy to control the e-paper without the overhead of I2C communication with PCF8574.

The CP2104 circuit is changed to bus powered, so it consumes power only when connected to a host. The LDO is changed to XC6220B331MR-G which has a lower quiescent current. These changes helped reduce the sleep current quite a bit.

The sleep current is well below 20uA now!

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