Smart AC Monitoring: Without the $500 Price Tag

[Tisham Dhar] has been interested in monitoring AC power and previously built a breakout board for the ADE7763. He wanted to find something cheaper and more modern. The ATM90E26 fit the bill. It can communicate via a UART or SPI, and has multiple metering modes. The problem? The evaluation module from Atmel costs about $500 (and for [Dhar] $800 Australian), although the part itself can be had for under a buck in bulk. (Atmel even sent him three samples for free.)

[Dhar] put the low voltage components from the reference design on a PCB and pocketed the difference in cost. So far, he’s tested the setup with a Teensy and low voltage measurements only. He plans to do a full test soon.

The test setup uses SPI mode 3 to talk to the processor. You can find the relevant code on GitHub.

We see a lot of energy monitoring projects go by. Of course, working on household wiring current can be dangerous, so be careful out there.

8 thoughts on “Smart AC Monitoring: Without the $500 Price Tag

  1. Yeah dev boards are done in very low yields for tons of ICs and are really marketed towards big companies … Making your own or hoping ebay, SPFE, adafruit has a breakout Is the only real way to do it for makers

    Some dev boards are ridiculous … Like an opamp on a pcb with a bypass cap for $50

  2. It is pretty understandable why such a board comes with a high price tag: the application is very specific and dangerous and it is probably expensively calibrated to meet those 0.1% precision requirements. It would be pretty hard to get that done diy.
    If you don’t want to go to whole house measurements, you can always buy one of the energy meter plugs and read that. Some serious ones even have an eeprom with calibration data so I suppose it is factory calibrated.

  3. This is a revenue grade metering chip which is probably way overkill if your hacking something together. Kill-a-watt meters are pretty cheap, if you’re just interested in how much your tv consumes.

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