ACS712 AC Current Sensor

Application

This sensor is currently used to measure mains AC current draw as part of a home power usage monitor.

Configuration

Details pending

Hardware

The ACS712 sensor comes in several variants designed to measure over different current ranges—5A, 20A & 30A. For my application I have used the 20A version. Driven by a 5V supply, this sensor then provides an output voltage in the range 0 – 5V when measuring current in the range 0 – 20A. Even though the recommended limit on most domestic power circuits in Australia is 10A, the use of 20A circuit breakers is quite common so it was considered wise to allow for sensing across the full current range—i.e. output in the range 0 – 5V. Given that the ESP32 ADC is limited to a range of 0 – 3.3V, this necessitates the use of a voltage divider on the relevant ESP32 input pin.

Further details pending

Software

Details pending