Hi, this is my breathalyzer project. It's just something fun that I have been wanting to make for a while now. It uses an atmega328, alcohol gas sensor from Sparkfun, and a small graphic lcd from Sparkfun. It is very simple in operation.
1.When first turned on, it goes through a 45 second warm up period so the alcohol gas sensor has time to warm up.
2.After the warm up period, the screen says that the breathalyzer is ready for you to blow into. The dot above the bar shows the value that the sensor has to pass to reset to the ready state.
3.When you are ready to blow, you close the lid and blow into the hole on the longer side of the altoids tin.
4. After you blow into the breathalyzer, it shows you the maximum value that you blew and goes into the waiting mode. It also marks a dot above the bar at the highest value that was blown since being turned on.
5.Once the sensor reading passes the first dot, the breathalyzer goes back into the ready state and still shows the highest value blown.