After buying a new Philips Sonicare toothbrush I was surprised to see that it reacts to the insertion of a brush head by blinking an LED. A quick online search reveals that the head communicates with the toothbrush handle to remind you when it’s time to buy a new one. From the Philips product page: seems to be REALLY smart! Reverse Engineering Looking at the base of the head shows that it contains an antenna and a tiny black box that is presumably an IC. The next hint can be found in the ma...
