[zmashiah] has a nice Nova tube amplifier in his living room, and he often forgets to turn it off once he’s done listening to music. He feels guilty when this happens, as it not only shortens the lifespan of his stereo, but it’s not exactly the greenest behavior either. Rather than let his receiver idle any longer, he built a simple device that automatically turns it off when he forgets.
He wired an Arduino to the line level output of the receiver, sampling the audio every two seconds. When five minutes pass without an audio signal, the Arduino sends an IR command to the receiver, turning it off.
He says he’s aware that it might be overkill to use an Arduino for this application, but that he would rather fork out an extra dollar or two instead of spending hours poring over AVR assembly code. While we’re all for efficiency, we can’t exactly argue with that logic – time is money!
[zmashiah] is kind enough to include his schematics as well as the code for his project, so be sure to check it out if you occasionally forget to turn off your IR-enabled appliances.