An "ingestible sensor" doesn't sound like the tastiest of snacks, but soon it might be just what the doctor ordered. A tiny microchip which activates upon contact with stomach acid has recently been given the green light by health regulatory agencies in the US and Europe. When the sensor is swallowed, an external patch picks up its signal and shoots a message over to whoever it's supposed to. The technology is aimed at tackling an issue known in the healthcare biz as compliance -- or, following instructions. Correct timing and dose are important for many drug
