Maker SHED

The DrinkShield is an open source Breathalyzer kit for the Arduino. It's a great starter kit that was originally designed for Hackerspace parties. The DrinkShield can work as a standalone breathalyzer or you can connect it to a computer and interact directly with the results. Source code repository comes with a game to use as a proof-of-concept.

Arduino library and example code included. This allows for a very simple way to handle auto-calibration of the MQ-3 sensor and retrieve readings as well as handle the light bar and player lights.

Note: The DrinkShield is for entertainment purposes only. Arduino not included and is required.

• Arduino library and example code included. You can download them from Google Code.
• Instructions for making the DrinkShield can be found here.

The DrinkShield is an Arduino shield that converts an arduino into an Open Source Breathalyzer.  It come complete with a light bar to show the intoxication 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 DrinkShield you also get a GPL game that lets you play with your friends and keep high scores!

The DrinkShield itself is licensed under the Creative Commons license and is free to modifications.  The libraries and Source code are licensed under the GPL or public domain.  It comes as a kit and is a really fun starter project to those just learning how to solder.  This kit is specifically designed for Hackerspaces around the world.  A Hackerspace can host a class and afterwards celebrate by throwing a party!

Many breathalyzers on the market have problems where the sensor fails after a few uses.  This is typically because of a hardware potentiometer to calibrate the sensor.  The drink shield eliminates this by taking air samples.  This can be controlled easily through the library.  Example:

DrinkShield ds(0,1);   // Drink Shield board version 0.1 defined in object ds
ds.autocalibrate(20);  // Take 20 air samples to determine a baseline

Once the device has been auto-calibrated (Can be called over the serial connection as well) you can simply use ds.getReading() to return a result if one exceeds the determined threshold.  This makes dealing with some of quirky readings with the MQ-3 sensor a snap.  There are also very easy functions for handling the light bar and keeping track of the Highest measurement per blow.  Having the additional player ready lights and sample game code will get you started in developing your own unique uses for this Open Source breathalyzer.

Version 0.1 of the Drink Shield teaches the use of shift registers to control all the lights in the project.