Side effects of a rabies vaccine I needed hit me about ten hours after the shot. The following 36 hours were brutal. I shivered all night long, despite it being June in Virginia and despite the two comforters swadling my body. At first light, my forehead burned with fever. Miraculously, a package arrived the same day containing a TempTraq bandage ($24.99 each) for me to test. Even though this smart thermometer is meant for babies, I slapped it onto my own skin and instantly had my suspicions confirmed: 102 degrees Fahrenheit.

Over the next few hours, the TempTraq monitored my fever and alerted me via my smartphone every time my temperature crept above 100.4, a mark that I could customize. The TempTraq's 24-hour battery life was more than enough time for my fever to break, and for me to watch it happen. This incredible invention is a one-time-use patch, and given the price, parents and caretakers wouldn't want to burn through one every day, but a few times a year, it could be an invaluable piece of at-home health tech.

Design, Price, and Use
The TempTraq is a disposable adhesive bandage, a little smaller than a playing card. Inside is a thin and flexible battery that you can't even notice, plus a few other electronic parts for measuring temperature and transmitting the results to a smartphone connected via Bluetooth.