I made these for my dad, who works as an AC and refrigerator technician and bought a couple of cheap digital thermometers. They work fine, however they use AG13 batteries and don't have an off switch, draining the batteries when not in use. Just soldering the battery contact points to a single AA battery holder and a switch, he can now turn them off whenever they are not in use and use more commonly availeable AA batteries.

Print Settings

• Printer: Hellbot Magna I v2
• Rafts: No
• Supports: No
• Resolution: .2
• Infill: 35%
• Filament brand: Any
• Filament color: Any
• Filament material: Any

Notes: Pretty much any setting should be able to print this, I went for .2 height and .4 width which is pretty standard. I used some spare HIPS filament I had lying around, but any material should do, just don't forget the thermometers in your car on a hot summer day like my dad did if you go for PLA.

Post-Printing

Materials:

• Soldering iron and soldering tin wire
• Single AA battery holder and battery
• A 10 x 15 on-off switch
• Some cable (optional, heat shrinking tubing for cleaner results)
• 4 screws (I used some pc case ones I had on my desk)
• Since its a DC circuit, do take into account which side your batter holder face (don't worry, since it's a tiny current the worst thing it can happen is that it won't turn on). Below I made a simple drawing of the circuit.

Once you solder everything then you can screw the battery holder and put both the thermometer and the switch into their place (make sure you pass the switch cables through the holes before soldering though). Do the same for the cover and you are done!