I just ordered an mq-3 alcohol sensor from sparkfun. Here's the sensor https://www.sparkfun.com/products/8880
and here's it's datasheet http://www.sparkfun.com/datasheets/Sensors/MQ-3.pdf
. I would like to make a breathalyzer that is somewhat accurate. Btw, I won't be using this to judge whether or not I can drive safely. I'm just looking for more accuracy than "buzzed", "drunk", and "dead".
To calibrate this sensor, they recommend using .4mg/L (200ppm) alcohol concentration, 21% Oxygen concentration, 65% relative humidity, at 20 Celsius.
I'm pretty sure I can create the above environment by evaporating .5ml of alcohol in a 1 liter bottle of ambient air.
Since I'm using this sensor as a breathalyzer, should I use ambient air or air from my lungs (15% Oxygen, 90% humidity at 36 Celsius) in the 1 liter bottle for calibration?