Archive for the ‘MQ-3 (alcohol)’ Category

The Jacket That Tells You You’re Drunk

Thursday, October 13th, 2011

[Matt Leggett] designed a jacket that is telling you whether you are able to drive or not:

Included in the jacket are an Arduino microprocessor, an alcohol sensor, and a series of LED’s that “provide an elegant solution to the drink driving problem.” A breathalyzer located in the pocket of the jacket, analyses the sample and then lights, that are stitched into the forearm, indicate how drunk you are. The LED lights glow when alcohol is detected and the brighter they glow, the worse you are.

via []

Arduino Breathalyzer: Calibrating the MQ-3 Alcohol Sensor

Thursday, September 23rd, 2010



[Nootropic Design] explains the use (and the approach) to one of the most interesting sensors I’ve seen lately: 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 gathering”, I found that this task is not as easy as it sounds.

The electronic circuit is explained and Standard Firmata used to visualize the data in Processing.

The most interesting part in the article is when [Michael] tries to calibrate the sensors, by calculating the BAC (blood alcohol content).

It’s really hard to calibrate this sensor for even an approximate BAC reading. It’s even difficult to correlate readings to looked-up BAC values. There are many environmental factors that affect the resistance within the sensor (humidity, temperature, oxygen concentration), and this is only a $5 device anyway. And as evidenced by the lack of consistency between online BAC calculators, there’s not even concensus about how to compute BAC. Law enforcement agencies have much more sophisticated breathalyzers, and often rely on actual blood tests or urinalysis for evidence.

Nevertheess [Michael] provides sketches, codes and everything to make the sensor work. You can’t always expect that precision from a 5$ sensor. Thanks a lot, we really appreciate your work: this is the more complete MQ-3 guide up to now.

via [nootropic]




Open source Breathalyzer? There’s a shield for thatOpen source Breathalyzer? There’s a shield for thatOpen source Breathalyzer? There’s a shield for that

Friday, September 17th, 2010

I was really impressed from this instructable on a brethalizer microphone. [Caring Smith] and [GfxHax] worked on a more reliable project: a DrinkShield.

The GfxHax drink shield is an Arduino shield that converts an arduino into an Open Source Breathalyzer.  It come complete with a light bar to show the intoxiciation levels.  There is a series of 11 lights down one side of the shield that go from green to yellow and ultimately to red.  There are also player ready lights.  Why are there player ready lights?  Well, this is because the shield is not just a standard Breathalyzer but can be used as a party game.  With the GfxHax drinkShield you also get a GPL game that lets you play with your friends and keep highscores!  This software is licensed under the GPL so you can add features and will have unlimited free updates to new versions.

via [MAKE] source [GfxHax]