Category Archives: opto-isolator

Opto-Isolating Automatic Cat Feeder Problems

When you buy an off-the-shelf automatic cat feeder, you might well expect it to do the one thing it’s supposed to do. Feed the cat. Well, at least as long as you do your part by keeping it filled with food nuggets. [Stephen] had the sneaking suspicion that his feeder was slacking occasionally, and set out to prove this theory.

He had a few ideas for approaching the investigation. One was to set up a web cam, but that proved unreliable. Another idea was to log the weight changes of the food bowl. This seemed like a possibility because the …read more

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Posted in automatic cat feeder, misc hacks, opto-isolator, reed switch | Leave a comment

Innocent TV Imprisoned Behind Mirror

After following along with all the Magic Mirror builds, [Troy Denton] finally caved in and started building one for his girlfriend for Christmas. These popular builds are all pretty much bespoke, and this one is no different.

His victim TV didn’t have the ability to be switched on and off by the Raspberry Pi using HDMI/CEC, so he came up with an alternative. He got a couple of opto-isolators and soldered one to the on/off button on the TV’s control board. The Pi didn’t know whether it was switching the TV on or off, it just knew it was switching …read more

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Posted in hardware, Magic Mirror, opto-isolator, Raspberry Pi, ultrasonic sensor | Leave a comment