A breathalyzer is a generalized trademarked name for devices used for determining blood alcohol content from a breath sample. This means the device can detect from your breadth, the amount of alcohol you have taken. This device becomes very useful when you consider several cases of accidents caused by drunk driving. With this device, you can easily warn the driver of a car when he/she is too drunk to drive a car. It is important to note that this project is not accurate enough to replace the standard breathalyzer and you shouldn’t drink and drive.
For this project, we will be using the MQ3 alcohol sensor. It is a cheap semiconductor sensor capable of detecting the presence of alcohol in air at concentrations between the value 0.05 mg/L to 10 mg/L. The sensor uses a chemical reaction to determine alcohol level and the primary sensing element in the sensor is SnO2, the conductivity of SnO2 is low in clean air but increases as the concentration of alcohol gas in air (breath) increases. It has high sensitivity to alcohol and has a good resistance to disturbances and noise from things like smoke and gasoline.
Arduino Breathalyzer Using MQ3 Gas sensor and OLED Display – [Link]
Today I am going to discuss how to make a very simple DIY Breathalyzer using Arduino UNO and few external components. Ana Carolina designed this project as an instructable in instructables.com. This is a low-cost project and a useful one too. If you have no idea about what breathalyzer is, let me explain briefly: A breathalyzer is a device for estimating blood alcohol content (BAC) from a breath sample. Check the link given for more information.
MQ-3 Alcohol Sensor
128×64 LCD (Liquid Crystal Display)
7 × 330 Ohm Resistor
7 × LEDs (1 Red, 2 Yellow, 3 Green and one other color)
Soldering Iron (optional)
Solder Wire (optional)
This project is very simple. Here we are using an array of six LEDs and a 128×64 LCD to display the alcohol level. The presence of alcohol is sensed by an MQ-3 alcohol sensor and then analyzed by an Arduino board. We are using Arduino UNO in this project, but any model can do the job.
Three Green LEDs represent that alcohol level is OK and within the safe limit. Two Yellow LEDs are used to describe that safe limit is going to be reached, and you know it well why the Red LED is there. In fact, those LEDs are used just to give you a quick idea. If you want to know the exact value, the display is there for you.
You can tweak the program and re-calibrate the breathalyzer. But you must remember that breathalyzer doesn’t precisely measure your blood alcohol content, rather it estimates a value from the amount of alcohol in your breath.
You can make the circuit also on PCB or Veroboard. But for the prototyping purpose, the breadboard is the best choice. You can see how straight forward the connections are.
Some part of the original code was in Portuguese. So I have translated it into English. Also, the original code shared by the author in instrucatbles.com is a buggy one. So, I recommend you to use my bug-free code instead of the original one.
Please note that you have to download and add the u8glib library in Arduino IDE beforehand. It is very important. You can either download the u8glib v1.14 library for Arduino directly or go to the site and choose what to download.
Follow the given steps to add a .zip library in your sketch: Open IDE and click on Sketch → Include Library → Add .zip Library. Now select the downloaded .zip library file. You needn’t unzip it.
When everything is done, verify and upload the code to Arduino.
I must not recommend you to drink alcohol just for testing the breathalyzer. Rather get a towel and spray alcohol on it. Now hold the towel in front of the sensor. Move it back and forth to observe the change in reading. It may take a while for the breathalyzer to stabilize.
Consider watching the video for a better understanding:
Knowing the amount of alcohol you drunk is becoming easier using the iBreathe Breathalyzer project by Dave Clarke. You just have to blow in the alcohol sensor, then it pings the result to a smartphone app and to the cloud to document it as a table so you can see alcohol intake through time.
This breathalyzer with a custom Beer mug casing will let you know where do you stand on the scale form “Sober as a judge” to “Hangover incoming”!
Below the (foamy) surface, it has substance too: along the 3D-printed casing, it features an Alcohol click sensor hacked to work with 3.3V, a customized Hexiwear interface, and a smartphone app.
Developed by MikroElektronika, Hexiwear platform combines the style and usability found in high-end consumer devices, with the functionality and expandability of sophisticated engineering development platforms, making Hexiwear the ideal form factor for the IoT edge node and wearable markets. It is completely open-source and developed in partnership with NXP.
This contest emphasizes the role of Hexiwear as the foundation for future IoT inventions. This powerful IoT development kit is a small and sleek, low-power device packed with sensors to quantify yourself and the world around you. Wirelessly enabled, it can connect both to devices nearby – or to cloud servers far away. With Hexiwear you can create your own smartwatch, remote sensor tag, or sophisticated home controller. Plus, it comes with preloaded apps to give you a fast start.
The Hexiwear Docking Station is an expansion board for Hexiwear, the wearable IoT development kit. It provides an interface for programming, debugging, and enhancing Hexiwear with additional functionalities by adding click boards.
Alcohol click carries an MQ-3 Semiconductor sensor for alcohol. The gas sensing layer on the sensor unit is made of Tin dioxide (SnO2), an inorganic compound which has lower conductivity in clean air. The conductivity increases as the levels of alcohol gas rise. Alcohol click has a high sensitivity to alcohol and it can be used to detect alcohol in concentrations from 0.04 to 4mg/l. To calibrate the sensor for the environment you’ll be using it in, Alcohol click has a small potentiometer that allows you to adjust the Load Resistance of the sensor circuit. Alcohol click communicates with the target board through AN (OUT) mikroBUS line. It’s designed to use a 5V power supply only. While Hexiwear’s analog input is 3.3V, this sensor was hacked by adding a voltage divider on the output pin of the Click Board.
A speaking version is an update to the original project. For more details and step-by-step tutorial go to the project page on hackster.io to get a complete walkthrough, including descriptions, 3D models, and code snippets.
The deadline for the contest has passed and winners will be announced on 21 Oct 2016. More information about other contestants are available here.