How to Make Breathalyzer Using Arduino and 3D Printed Parts

Hello readers, In this instructables I will show you how you can make a breathalyzer at your home.

Few also call by name alcohol meter, This tiny device helps to identify alcohol content in a person when they breath out.

This device works like the usual meter but the accuracy is not like the real ones, Well the device that we use is for educational purposes where in you can learn how these gadgets work and the principle behind their working.

The logic behind the working of my alcohol detector also called as breathalyzer is very simple, Im using MQ3 sensor and it is know as alcohol sensor.

I will use OLED screen to detect the level of alcohol and if the detected amount is high it will display as “High levels” and if everything is normal it will display “Low Levels”

I wanted to make this as small as possible so the choice of board was Arduino nano, I know there are other ways to even more shrink the component size but considering the cost effectiveness to the performance ratio this is the best.

I will also be making an upgraded version of this in the future, if you have any ideas that I can implement additionally let me know that.

Now to begin with I have given all the materials to build this, Free circuits and codes! Well what is missing? Just the time of yours to build this!

Here are the list of materials that you will need to build this project and most of these are easily available at your nearest hobby electronics shop

Arduino Nano

Mq3 gas sensor

OLED module

Jumper Cables

3d printer

PLA filament(color of your choice)

Arduino IDE and Programming Cable

Tinkercad Software(if you want to customize my model)

Slicing Software

Nail polish remover (For Alcohol detection)

The Important part of this project is the enclosure and to make it accessible for anyone 3d printing is the best option.

I have made the designs using Tinkercad, I had to make several designs to finally come up with more reliable version.

Once I had the design I sliced it with slicer and used PLA filament to print the parts

At the time of slicing you need to take care of settings, I have added the settings that I followed and you can use the same.

There is no need of any rafts or supports at the time of print since there is no hanging parts here.

The printing time is under 90minutes for both the parts combined, The choice of PLA filament color is left to you.

I chose orange for the base and white lid for the top these color would make the project look more appealing

I will begin this project by uploading code to Arduino nano board first, This is very easy all you have to do is connect the nano board to computer via programming cable.

Open Arduino IDE and simply copy and paste this below code, Select proper port number and board type and click on upload button.

If you face any issues make sure that the OLED library is present you can get it on Arduino site, install it and upload the code and now the code will be uploaded to board.

Disconnect the USB and now we can build connection among the components.

Let me explain you the circuit connections here

The circuit mainly has 2 major components apart from nano itself

The MQ3 sensor detects the alcohol and to display that we are using OLED module

MQ3 sensor

This sensor comes with 4 pins out of which we are using 3 pins

The Vcc and Gnd and connected to 5v and gnd pin on the nano whereas the A0 is connected to A0 pin

OLED

It has 4 pins out of which 2 are for power supply, Vcc and Gnd are connected to same pins as on the mq3 sensor.

Scl and Sda are connected to A5 and A4 pins of the nano board

Here I have combined the Gnd and Vcc pins of both the components and connected to nano so we are using a few less cables!

I have made the 3d printed parts considering the size of these electronics, No worries you can expect same fit like me since the component comes in standard sizes.

To begin with let us start by coupling nano board, Add drops of mild hot hot glue to the base and place the nano, Gently press on this for some time and when its dry release

Make sure the slot is aligned as per the 3d printed part, Next comes the sensor and screen part.

For this we have top plate, you might need to check if the sensor enters this hole first before moving on to the gluing part.

For OLED screen I tried using double sided adhesive, It doesn’t seem to work well! So I decided to use hot glue, I know most of them suggest not to use but it will not make any issues.

Add tiny amount on the sides and place the OLED and allow to dry completely, Now on the next turn we have Mq3 sensor.

This does not need any glue it follows the press fit type of coupling, Adjust the sensor accordingly, Now couple the lid to the base.

I recommend using hot glue instead of super glue, This is because if any drop of superglue spills inside during this process the chances of circuit not working at all is very high.

So avoid the risk by using hot glue, Add over to the edges and then gently press the 2 layers on top of each other, Now the project is almost ready and we can test it out.

Using this is very easy, All you have to do is connect the device to any USB source and wait for OLED to show "warming up" Message.

You have to wait for a minute to have the device ready for use, After the sensor is heated up the OLED shows Low levels as a message at this point the device is ready for using.

I don't drink so i will be using nail polish remove to test this device, I poured the liquid onto a small cap and bought it close to the sensor, The OLED immediately shows high levels.

The device worked well for me and i tested with a lighter also and i was able to see good results.

Now after your work is done, simply plug out the USB and that's it all you have to do.

To use the device again you need to wait until the sensor gets warmed up, Thats all about this alcohol meter hope you will enjoy building this device, Thank you for showing interest till here.

Video of complete build is here, if you missed to check the setting on the 3d printing part you can simply refer this video it has more detailed view.

That is all about this project, If you have any more ideas like this or if you made this project don't forget to share. Thank you and happy making.