ESP-WROOM-32 breakout board to connect it to a Waveshare E-Ink display.
Inspired by article Ausdauernde Infotafel from German computer magazine c't. Example arduino and server software can be found here.
Input voltage is connected to a voltage regulator jack and directly to Pin6/IO34/ADC6 for monitoring. Hence input voltage must be below 3.6V. I use 2xAA together with a step up regulator. Additionally I connected a pad for Pin8/IO32/ADC4/TOUCH9. Haven't used it yet. Maybe for a touch wakeup or status LED.
Display connector pin assignment is identical to the Waveshare hat connector.
Rev A2 PCB can be ordered e.g. via aisler.net: https://aisler.net/p/HSIWEKKI
Components needed in addition to PCB:
- Of course an ESP-WROOM-32 (or footprint compatible)
- Waveshare E-Ink display
- 3.3V voltage regulator or other 3.3V source
- Battery + holder of your choice
- 2x ~10kΩ pullup resistors R1+R2
- 2x tactile switch (included in aisler precious parts)
- 1x JST-PH 8 connector header+housing (included in aisler precious parts)
- 1x JST-PH 2 connector header+housing (included in aisler precious parts)
- 10-15 JST-PH terminals (included in aisler precious parts)
- Crimp tool for JST-PH connectors
- 3.3V capable USB-TTL adapter for programming
This a minimalistic board to save power. No USB included. So you need an USB-TTL adapter that is capable of doing 3.3V. This one works for me under Linux.
To upload an arduino sketch/flash firmware:
- Connect the USB-Adapter GND/RX/TX to the board. Most adapters need RX board/TX adapter and TX board/RX adapter. If that doesn't work try RX/RX+TX/TX. To check press the Reset button. The serial monitor must show the ESP33 boot log.
- Press and hold the Boot(loader) button, shortly press the Reset button, then release the Boot button. Log should show the ESP32 entering bootloader mode.
- Now stop any serial monitor (Arduino IDE does this automatically)
- Upload the sketch and wait until completion
- Again press the Reset button
- Restart serial monitor (Arduino IDE does this automatically)
- Trace width power supply + GND
- Via min size 0.65mm (=drill + 0.25mm)
- Initial revision