Sunday morning musings.. many of the past posts were all about how we might ‘devine’ the direction of the wind. We DIYers build our houses with thoughts of such things. But what follows are tools and knowledge we might add to our tool kits, and perhaps it will help make us even less dependent on utilities? Can you deploy an Arduino to manage your dump loads?
Thanks DIYer Steve Spence, finally! free tools, a free environment, and the easiest path I’ve ever seen to learning how we might leave a micro in charge of looking after our investments..
I had many reasons to build my own version of a Kill-A-Watt Meter. I needed more flexibility (DC as well as AC, production and consumption), I needed higher than 15 amp load monitoring, I needed data logging, and I needed the ability to make things happen based on the data I was collecting.
I built an Arduino based power monitor, that at it’s very basic function, monitors the amps flowing between two devices, and the voltage being monitored. By multiplying these two values, I came up with the watts being produced or consumed.
Amps * Volts = Watts (DC, AC works a little differently)
Now it was time to measure the time value. I reported the time passed during the monitoring session, so I have an Hour Meter, and by multiplying that against amps and watts, I get amp hours and watt hours respectively.
Amps * Hours = Ah
Watts * Hours = Wh
I can transmit the data to a computer using serial or ethernet, make decisions (like turning loads on and off based on voltage and or current flow using SSR’s or Relays), and with a SD Card slot and a little bit of code, I can periodically log the data to the SD Card.
Future upgrades could also include frequency monitoring and power factor (with AC Watts). This design is very hackable, so make it your own by applying your own ideas and requirements.
Resistors for voltage divider
For details on code and schematics, please see