Pololu Current Sensor 3.3 ~ 5.5V (logic) .045V/A output ACS711EX -31 ~ +31A @ < 100v in
Current sense: 0.045 V/A (at 3.3 Volts, output is proportional to Vcc)
Minimum logic voltage: 3 V
Maximum logic voltage: 5.5 V
Supply current: 4 mA
Dimensions: 0.7″ x 0.8″
Maximum Current input: +-31 Amperes (May tolerate up to 100ms at 100 Amp, but not recomended or measurable)
Mazimum Voltage input: 100 Volts is the maximum recomended voltage. (Exceeding this voltage break voltage isolation and damaged attached devices and controllers)
(Usage information and diagrams provided by Pololu)
Operation of this sensor is relatively simple, all you need to do is put IP+ and IP- in series with your load (cut the source or drain line of your device/circuit and solder either side of the wire to IP+ and IP- respectively). Once the board is powered it will then produce an output voltage on the OUT pin that represents a number between -31 Amperes and +31 Amperes.
The FAULT output should latch high if the current limit is exceeded so that you can track whether or not your reading limit has been reached.