Arduino Breathalyzer: Calibrating the MQ-3 Alcohol Sensor

The MQ-3 is an alcohol gas sensor that is available for about $5 from Sparkfun, Seeed Studio, and others. It’s easy to use and has sparked the imagination of anyone who has dreamed of building their own breathalyzer device for measuring the amount of alcohol in the human body. I got an MQ-3 sensor a couple of months ago and have spent a lot of time trying to figure out how to do this. After lots of “data ga ...

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Calibrating sensor input using Arduino

This example demonstrates one techinque for calibrating sensor input. The Arduino takes sensor readings for five seconds during the startup, and tracks the highest and lowest values it gets. These sensor readings during the first five seconds of the sketch execution define the minimum and maximum of expected values for the readings taken during the loop. Circuit Analog sensor (e.g. potentiometer, light sens ...

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