[haqnmaq] admits that he suffers from Obsessive Compulsive Disorder and on occasion, can be found washing his hands up to 20 times an hour. Very distrustful of cloth towels, he exclusively uses paper towels to dry his hands, to the tune of 2-3 rolls a day. In an effort to lessen the impact his OCD has on the environment and his wallet, he decided to build an automated hot air hand dryer using a 555 timer, which doubles as his entry in the 555 Design Contest.
The concept behind his project is to use a hair dryer as a hot air source, relying on a phototransistor and a pair of IR LEDs to detect when hands are placed under the dryer. When a pair of hands are detected, a relay is triggered and the hair dryer is turned on. Once the dryer has run for a pre-determined but adjustable time, the relay is opened, and the hair dryer turns off.
It’s a pretty simple project, but one that is quite useful, whether you suffer from OCD or not. The only thing he might want to watch out for is the restricted air flow to the dryer, since it is mounted in a sealed plastic container – a few seconds with a hole saw should remedy the problem quite easily.
Want to see the hand dryer in action? Keep reading for a short video demonstration.