Hello everyone.
For the purpose of the project I'm building, I want to identify whether the power that reaches the Arduino comes from the battery (9v) or whether the controller is connected to the PC via USB.
How can I check this?
Thank you!
Using a DVM.
you mean DVM ?
Digital volt meter. Or DMM too, Digital Multi Meter.
Use Serial.begin(); if it returns a true You have USB, else battery is powering things.
Are You sure what happens if both USB and battery are connected?
Serial.begin() is a void function.
Correct! Serial. available(); should have followed it.
But if power is coming from a dumb 5V source into the USB connector, such as a USB charger or powerbank, the Serial function wouldn't detect anything.
Seems like the safest way is to feed a resistive divider from the Vin pin, and take a voltage reading on an analog pin. If the battery is present, it will be providing power to the circuit, and the voltage measured will be a divided down 9V. Otherwise Vin will be a divided down 5V or 4.7V or 0V, depending on the Ardiuno.
You're thinking of if (Serial) and that only works on boards with a native USB interface. On something like an UNO it will always give true no matter what.
Oops.
Thank you it worked !
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