Hand tools and fabrication machines
I got a new BBQ grill recently and I wanted to be able monitor the meat temperatures from my smartphone. I looked into commercial products, but they were quite expensive and the apps didn't look all that great. Additionally, the Traeger wood pellet grill that I bought allows a "set and forget" grilling method. I'm lazy and wanted to be able to just put the meat in the grill and have my phone alert me when it's done. Additionally, I love to build my own stuff so I can customize it exactly how I want it.
So I just bought a couple of grill thermometers and a Particle Photon to measure the temperatures. The Photon posts the temperature up to the cloud every minute as public variables. I also wrote an Android app that fetches the temperatures from the cloud. The app will graph the temperatures over time and has the ability to set a target temperature that one achieved will alert you with an Android notification.
I took an old phone charger and removed the case and wall outlet prongs. I had an old power cord and socket from an electric shaver I was able to wire up to the phone charger. You can see the large white plastic divider in the image I used to isolate the photon and low voltage wires from the high voltage guts of the phone charter. They are all put into a weather proof box I got form Digikey. I glued a couple of rare earth magnets inside the box so it can just stick to any location of the grill I place it on.
Note: the 2.5mm headphone jacks I got are a little short. This means if you push the probe tip all the way in, it will short and not work correctly. I just ensure I back the probe tip out by 1mm when I connect them.
At the time, I had the photon with headers and the battery board, so I used both. You could eliminate the battery board if you purchase a lead-less Photon and solder the wires straight to it.
With a multimeter and a careful hand, I was able to probe the Traeger control panel and find the Line and Neutral 120v points that I could solder the other end of the shaver cord to. These points are only live when the power switch of the grill is on, so that's a bonus. (Sorry I don't have pictures of that, but I do remember they are directly behind the LED panel along the bottom edge).