measure USB voltage on Lilygo ESP32 - SIM800L

Projects Programming
1

Dear all

I am trying to program an ESP32 SIM800L, sending an SMS when a trigger wire is interrupted.

I adjusted the code I found here here

I would like to power the Lilygo ESP32 via the USB-C.
I would like the board to send an sms when the voltage starts to drop below a certain value.

Is it possible to measure the 'incoming' voltage via the USB ?
(I have been googling, but I haven't found anything yet).

Regards
Diederik

2

this could be useful to detect when a board is being disconnected

i would think you would need to wire a connection to the Vbus and a resistor divider to an analog input.

3

I am trying to figure that out, but where do I find Vbus on the lilygo ESP32 ?

Regards

4

it's most likely an input to the power circuit