An enclosure for the 2.9" e-ink display from Waveshare. Powered by two small solar panels.

I'm using it to display the output from my solar panels on my roof.

A NodeMCU ESP8266 is connected to a 18650 3.7V Li-ion battery which is charged by the two solar panels on the box. See the circuit diagram for detailed overview of the setup. The connection to the display is only hinted but I used the following connections;

• Busy --> D2
• RST --> D4
• DC --> D3
• CS --> D8
• CLK --> D5
• DIN --> D7
• VCC --> VCC
• GND --> GND

The ESP8266 is in deep-sleep mode to conserve energy and wakes up with regular intervals to update the info on the display.

Parts list:

• 2"9 inch display (Three-color): https://goo.gl/3dzN7N
• NodeMCU: https://goo.gl/nDuAkv
• Solar panels 6V: https://goo.gl/6mY89d
• TP4056 Charge protection board: https://goo.gl/a9wdzB
• 1 x 18650 3.7V li-ion battery.
• 3 diodes.

Note: I measured quite a difference in power consumption in deep-sleep between the various NodeMCU boards I've bought from various sellers. Up to 200 (!) times more power used in deep-sleep for the least efficient one compaired to the most efficient.