Isolated AC Power Measurements with Arduino
Being able to measure AC loads is very handy for a whole-house automation system. Measuring draw on the grid can allow you to see where your power is actually going. The PQduino wirelessly measures an AC load up to 5 amps, with a 10 amp peak. Sending the data over the air keeps your system much safer, as there’s no physical connection to low-power devices like a PC, and so the entire system can be fully enclosed to prevent accidental shock.
The UI design looks amazing, and a huge number of important parameters are displayed, including RMS voltage and current, active and reactive power, frequency, THD and much more. The data is presented in a clear, easy to read way, and there’s nothing stopping you from writing your own code to analyze or store the data in any way you please!
It’s even possible to measure a 3-phase system using three PQduinos and integrating the data from all three. With OTA updating, an installed system can be updated and upgraded without having to shut off power or even open the enclosure it’s installed in. Supporting both Wi-Fi with an ESP8266 and Bluetooth with an HC-05, you can do fast data transfers or go to a low-power mode using Bluetooth only.
While the main measurement transformer is only rated for 5A continuous, 10A peak, adding an external current transformer can easily expand the measurement range to whatever is needed. Just keep in mind that working with mains voltage can be dangerous — always remove power from all devices before working on them. Use the proper safety equipment, and if in doubt call a professional electrician to do the installation for you.