Brian Chamberlain
Software Engineer & Electronics Nerd

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Imperial Tea

Tea making with a touch of the Empire

Q: How to hack a high-tech tea maker?

A: Through the power line.

The full write-up and video is on Hackster. Check out the project on

This is what the power signature looks like when brewing tea. It's pretty clear when the power usage jumps straight up. That's the resistive heating element in the base kicking on. You see it turn off then the basket motor turn on. After a few minutes you see a tiny rectangular blip. That's the motor raising the tea basket back up after brewing. This is what we trigger off to play the WAV file. imperailtea power graph I captured the power usage with this rig I borrowed from work. It helps when you work at a electrical power monitoring company and are friendly with the support engineers. imperialtea test rig

This was the prototype circuit. imperialtea circuit prototype This was the AC power + transducer setup. It's pretty easy to make. You just take a 15 Amp appliance cable and cut it, slip the transducer on the hot line and re-crimp the lines. imperialtea current transducer

The final circuit for the project. I used two Arduinos. One to play the WAV file and one to sample the power and monitor the state of the tea maker. They communicate over a simple serial protocol. imperialtea prototype inside imperialtea prototype outside

Complete and working. You know it's working because the LED light is on. =) Watch the video to see the thing in action. imperialtea complete active

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