Arduino Fart-O-Meter

Arduino Fart O Meter

OH NO! He didn’t!

Yes I did!

My project is simple: Farting in a chair and sending the signal wirelessly to a panel that shows the intensity of the fart!

Words of caution: Please do not force yourself to fart, you might shit in your pants if you try to hard!

Thanks to all my friends who helped in this project! (and all my tester!)

Michaël Vachon
Steven Jolley (Fart NINJA)
Manuel Grégoire
Mathieu Desnoyers
Pier-Alexandre Fortin
Louis-Philippe Gagnon
Francis Leconte
Gaétan Mercier
Sébastien Choquette

Arduino Fart O Meter

Step 1: Component list

The project consists of two modules:

The emitter located on the chair and the receiver located somewhere else (e.g. on your desk).

Here is what you need to make a Fart-O-Meter:

1 x large protoboard PCB
1 x ATMEGA168/328 Arduino chip with bootloader
1 x LM117 – 3.3V regulator  (Sparkfun sku: COM-00526)
1 x 7805 – 5V regulator
1 x 1N4148 diode
1 x 16Mhz crystal
5 x 0.1uF decoupling capacitor
1 x 220uf 16V capacitor
1 x Green LED
1 x Bi-Color LED (or two separate green and red LED)
3 x 220Ohm current limiting resistor for LED
1 x 10K resistor for reset of the Arduino
2 x 100K potentiometer – one for gas sensor calibration and the other one for debugging
1 x Audio Jack 3.5mm use to connect the methane sensor
1 x 3.5mm audio jack  (Sparkfun sku: PRT-08032)
1 x 8 x AA battery holder
1 x 9V power clip – It connects to my 8 x AA battery holder
1 x Plastic enclosures
1 x FTDI Basic Breakout – 5V ( Sparkfun sku: DEV-09716)
1 x  MQ-4 – Methane Gas Sensor (Sparkfun sku: SEN-09404)
1 x nRF2401A Transceiver with Chip Antenna (Sparkfun sku: WRL-00152)

1 x Arduino (Solarbotics sku: 28920)
1 x shield (Solarbotics sku:16090)
1 x Transceiver nRF2401A with Chip Antenna (Sparkfun sku: WRL-00152)
1 x Servo motor

Hardware for receiver
1 x large acrylic/plexiglass sheet for mouting everything to it
4 x Silicone Bumpers – so the platform does not slip
4 x HEX 3/8 inch standoffs (Sparkfun sku: COM-00126 )
4 x 1/4″ Screws 4-40 Thread (Sparkfun sku: PRT-00447 )
4 x Machine Screw Nut – 4-40  (Sparkfun sku: PRT-10232 )
2 x 1/2″ Screws 8-32 Thread for mouting servo
1 x 8 x AA battery holder
1 x 9V power clip – It connects to my 8 x AA battery holder

Step 2: Tools

Here are the tools you might need:

1 x Multimeter
1 x Side cutters
1 x Nose pliers
1 x Lighter – for heat shrink and testing the methane sensor (yes, the methane sensor is sensitive to butane)
1 x USB cable for programming the Arduino
1 x Screwdriver set
1 x Sharp knife
1 x Set of drills
1 x Precision screwdriver set
1 x Double side sticky tape
1 x Duck tape
1 x Scotch tape
1 x Drill
1 x Safety glassesSchematic Arduino Fart O Meter

Be safe!

Step 3: What is a Methane sensor?

The MQ-4 can detect natural gas concentrations anywhere from 200 to 10000 ppm (Parts Per Million).
It is very sensitive and has a quick response time.

This sensor is analog and gives out voltage depending of the gas concentration. When there is no gas, the voltage read is around 1.3V.Otherwise, when you fart, it goes up to 5V!

Since it uses a small heater inside, it consumes 175mA!! It has to be considered when choosing the battery source.

Step 4: Transceiver NRF2401A

Sparkfun have this great wireless module called the nRF2401A Transceiver.

There is also a librarie to make it work with the Arduino.

You can make that module work in no time!

There is an important thing you should remember, the module works on 3.3V not 5V.

If you use a standard Arduino, you will need something to convert the signal down to 3.3V. The stock Arduino is 5V.
There is different ways to do so.

Here is a tutorial on Sparkfun website

Sensor Interfacing

Sparkfun also sells this ready made PCB board called Logic Level Converter (Sparkfun sku: BOB-08745)

I simply use a voltage divider to bring the 5V down to 3.3V

Read more: Arduino Fart-O-Meter

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