User Manual

You can read this pin's voltage, then double it, to get the battery voltage.

ENable pin

If you'd like to turn off the 3.3V regulator, you can do that with the EN(able) pin. Simply tie this pin to Ground and it will

disable the 3V regulator. The BAT and USB pins will still be powered

Alternative Power Options

The two primary ways for powering a feather are a 3.7/4.2V LiPo battery plugged into the JST port

a USB power

cable.

If you need other ways to power the Feather, here's what we recommend:

For permanent installations, a 5V 1A USB wall adapter (https://adafru.it/duP) will let you plug in a USB cable for

reliable power

For mobile use, where you don't want a LiPoly, use a USB battery pack! (https://adafru.it/e2q)

If you have a higher voltage power supply, use a 5V buck converter (https://adafru.it/DHs) and wire it to a USB

cable's 5V and GND input (https://adafru.it/DHu)

Here's what you cannot do:

Do not use alkaline or NiMH batteries and connect to the battery port - this will destroy the LiPoly charger and

there's no way to disable the charger

Do not use 7.4V RC batteries on the battery port - this will destroy the board

The Feather

is not designed for external power supplies

- this is a design decision to make the board compact and low

cost. It is not recommended, but technically possible:

Connect an external 3.3V power supply to the 3V and GND pins. Not recommended, this may cause

#define VBATPIN A7

float measuredvbat = analogRead(VBATPIN);

measuredvbat *= 2; // we divided by 2, so multiply back

measuredvbat *= 3.3; // Multiply by 3.3V, our reference voltage

measuredvbat /= 1024; // convert to voltage

Serial.print("VBat: " ); Serial.println(measuredvbat);