The I/O level of Arduino is 5V, and the e-Paper should be driven with 3V3. If your Arduino cant drive the e-Paper successfully, please try to convert the level to 3.3V
You can also try to connect the Vcc pin to the 5V of Arduino to see whether the e-Paper works, but we recommend you not to use 5V for a long time.
2. Why does the color of e-Paper look a little black or grey?
You can try to change the value of Vcom on demo codes.
3. Three-color e-paper looks more red/yellow than the picture on website?
Because of different batch, some of them have aberration. Store the e-Paper right side up will reduce it. And if the e-Paper didn't be refreshed for long time, it will become more and more red/yellow. Please use the demo code to refresh the e-paper for several times in this case.
3. Why my e-paper has ghosting problem after working for some days
Please set the e-paper to sleep mode or disconnect it if you needn't refresh the e-paper but need to power on your development board or Raspberry Pi for long time.Otherwise, the voltage of panel keeps high and it will damage the panel