How do you read the battery voltage for the new ESP32 V3 boards? Any suggestions are welcome.
I have seen this code to read analog signals. But which pin is connected to the battery? Pin 1?
Yes, indeed, GPIO1 is ADC pin
Do you know, how can i detect if the board is powered normal/ with the battery?
@mechanix your best bet is to do a bit of a guess on the battery voltage: a normal battery never goes above 4.2 or 4.3 volts, so if you read more than that, it’ll likely be due to USB power. On USB, I usually read about 4.8 volts.
I do have a piece of code somewhere that can detect whether the board is connected to a USB host (such as a computer or laptop), but it fails to register if it is connected to e.g. a powerbank or simply a USB wall adapter. So that’s not really useful for this.
Hello and many thanks for your reply!
That is what i am trying to have - a signal, when the power is disconnected. Basically, I want to store some variables in flash memory when the power goes out. I want to power it with onboard 5V pin, but i can also use usb port. So far i found only an idea with simple voltage divider (2 resistors) - to lower voltage under 3V and measure it on a pin. Can you advise?
The easiest should be the following:
- always read the battery voltage
- if the battery voltage < 4.3 Volts, then you are on battery power
- if the battery voltage > 4.3 Volts, then the battery is charging due to some power source (USB or 5V)
Since the battery voltage pin already has a built-in voltage divider, you shouldn’t require any modifications or additions.
I need to save the variables in the exact moment when the power goes off. The voltage at battery goes down, but not that fast. I think measuring this 5V pin can solve my issue.
Thank you for the time and help!