I Made a Fart Detector

Nothing stinks more than a fart chair that tells on you.

We have officially released our Arduino for Makers course and what better way to share that with you all than making an Arduino based project. For the last several years I’ve had “fart sensor” on my project to do list and it’s finally time to make it happen. 

1. The Actual Fart Sensor
2. Coding the Fart Sensor
3. Testing the Sensor
4. Adding the Fart Sensor to the Chair
5. Next Level Fartiness
6. Adding the Light and Buzzer
7. Who Had the Best Fart?

1. The actual fart sensor

The fart sensor not only detects methane from stinky farts but it can also detect carbon monoxide, hydrogen, natural gas, and even propane. There several other sensors like this, too. Certainly, this project can be more than just sensing methane from farts, but it can be useful in your home as well. 

2. Coding the fart sensor

To start, I used the sensor, an Arduino Uno (which is the same we use in the Arduino for Makers course) and then a tiny screen. Next, the coding for this was very simple and it took me less than 10 minutes to set up. This sensor works by checking the combination of all the gasses at once and then the tiny screen will give you a concentration number. Finally, I set the sensor to a numeric threshold so when it crosses a 500 threshold, the screen will light up with any words I code it to say.

3. Testing the sensor

Therefore, since this sensor also detects propane, we used a small propane torch (without lighting the flame, obviously) to test out the sensor. Unfortunately, not everyone can fart on command to test this out as many times as we did. Finally, with a completed set up, I added it to the chair to make this really come to life.

4. Adding the fart sensor to the chair

We found a rattan chair at our local Goodwill – we chose this type of chair specifically so that gas would pass through the holes of the weaved chair seat. First, on the underside of the chair I cut a hole in the elastic strapping to mount the sensor. Next, I tested using the propane to make sure that my hypothesis was correct – the sensor works perfect with the weaving of the rattan chair. Last, with the sensor mounted, it was time to take it to the next level. 

5. Next Level Fartiness

At this point, we’ve proven that the sensor works and will function within the chair. Next, we need to make this chair into a fart prank. First, we need to add a relay to the Arduino setup. We talk about this in the Arduino for Makers course – the point of the relay is to take the input from the Arduino, and you can use it to control the higher voltage output – like plugging in a lightbulb and a siren. A relay is a great tool to use to connect the Arduino to something bigger to take that project that requires more power to the next level. 

6. Adding the light and buzzer

Next, using the relay, I added a bright red light that we mounted hidden under the chair along with a buzzer. Using jumpers, I jumped the relay over to the Arduino – and by adding 6 additional lines of code, the light and buzzer worked! This is the perfect example of taking your base line Arduino and add things onto it a piece at a time – all of which are covered in the new Arduino for Makers course. 

7. Who had the best fart?

Since everyone on the team knew about the chair, we really couldn’t prank each other. Instead, we took the display from the practice seat progress chair we made a while back and hooked that up to the chair making the fart chair a game for the team. The highest fartiness score will win – trust me, it’s not who you think will win. Spoiler: it’s Meighan.

This project was ridiculous but it really shows you that basic electronics can make your project really cool – or really silly. Be sure to check out our new course Arduino for Makers!