One evening late in the summer, I decided to take a little dip in the hot tub before bed. I went out to the patio, swung back the cover and slipped in. As usual, there was the sting of hot water that always goes away after a moment or two. However, this time it just got worse! I quickly got out and discovered that the temperature was 112 degrees and climbing! The temperature controller had gone bad.

In this DIY Jake will build a new controller to replace the broken one in his hot tub. I guess this curcuit could also be used for a ton of other applications, use your own imagination.

Link: Op-Amp Hot Tub Temperature Controller

While drinking certain dark beers in the sun, I came to think about how to keep the beer cold until I finished it.
Normally this isn’t a big problem as I usually finish them before they get warm, but on really hot days this can be a problem. Having some hardware lying around in my apartment, I decided to build something that could keep the beer cool.

And the best of all – it’s powered over Cat5!