So how does HyGreen -- the proposed solution, now in testing phase -- work? It's a little like a Breathalyzer, but for hands. Each time they soap up, health-care workers will have to pass their hands under a detector located by the sink. If the hands pass muster, a wireless signal coming from the worker's badge will set off a green light on the sensor. Later, back in the patient room, another monitor will check the worker's badge and again flash green if their hands are clean. If not, the staff member will get a vibration reminder -- and probably also a talking-to, since supervisors will be able to check the signal log in real time.