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ArduSensor Fart Quickstart Guide



The Basics:


The fart sensor is actually a methane sensor used at very low values.  The sensor that we use at Qtechknow is not certified for using for anything but entertainment purposes. :)




First off, if you don’t know how to solder, go here to learn the basics so that you are thoroughly prepared to assemble your kit.


Parts in Kit:


Qtechknow ArduSensor Fart PCB (Printed Circuit Board)

Methane CNG Sensor MQ-4

10K Ohm Resistor – 1/4W

Male Headers (5)


Tools Needed to Assemble:


Soldering Iron

Rosin Core Solder

Safety Glasses

Safety Mask

Vice or Third Hand


You will need to get on your own:


Arduino Leonardo with micro-B USB Cable


Arduino Uno with USB-B Cable


When using lead, take precautions like:


  • Make sure to wash your hands with soap and water twice after you solder
  • Don’t eat the solder
  • Don’t touch your face or eyes after touching the solder
  • Wear a mask to prevent the solder smoke to come into your mouth, and inhale it
  • When working with hot solder, you especially want to wear eye protection, to protect your eyes


Assembling the Kit:


Take out the ArduSensor Fart PCB (green board) out of the the bag and put it face up into a vice or third hand.

Insert the methane sensor MQ-4 into the copper holes in the middle of the PCB.  Make sure that the “MQ-4” text is facing the “Fart” text when you insert.  It usually is a tight fit.  Make sure that all of the copper holes are lined up correctly, and get your parent to help push it in (should require a lot of force).

Take the PCB (and fart sensor) out of the vice or third hand.  Flip the PCB (and fart sensor) over, and then put back in the vice or third hand.

Put your soldering iron on one of the junctions where there is a copper hole, and one of the fart sensor legs popping through it.  

Wait three seconds, and then take your solder, touch it briefly to the junction, and then take your soldering iron away.  The junction should look something like this volcano shape:

Repeat this process 5 more times to the other joints with the copper hole and a fart sensor leg popping through it.

After you are done, flip the PCB over again so that the text and methane sensor are upwards, then put into the vice or third hand.

Take your 10K (Brown, Black, Orange, Gold) ohm resistor out.

Bend the leads so that they make an upside-down “U” shape.  

Put the ends of these two leads into the 10K ohm resistor footprint on the PCB and bend the resistor to the right a small bit.

Pull both of the leads from the underside, and push on the top so that the leads fit in the PCB.

Flip the PCB over and bend the leads of the resistor out in opposite directions.  

Solder the two copper holes that have resistor legs popping out of them (the same way you did before).

Trim the leads so that they don't poke you.

After you trim the ends of the leads, the whole PCB should look like this:

Take the 1 pin male header and 4 pin male header, and put them into these Arduino pins:  The 1 pin male header goes into A0, and the 4 pin male header goes into VIN, GND, GND, and +5V as shown below in the picture.

Place the ArduSensor Fart on top of these pins, making sure that the 1 pin male header goes into the 1 pin male header socket, and the 4 pin male header goes into the 4 pin male header.

Solder in place.  But make sure that you don’t put too much solder in, because that can cause the ArduSensor Fart to be permanently installed on your Arduino!

Wait for the ArduSensor Fart to cool off (around 20-30 seconds), then pull out of the Arduino sockets.  Now you are finished soldering your ArduSensor Fart!




If you haven’t downloaded the Arduino IDE, go here to download the latest version.  If you haven’t installed drivers for the Arduino (haven’t downloaded the software yet, or haven’t done this step yet):



If you have...

Arduino Uno

Arduino Leonardo


No drivers needed, proceed to the next step

Go here, then proceed


Go here, then proceed

Go here, then proceed



Put in your ArduSensor Fart to your Arduino like this: Put the 1 pin male header into A0, and the 4 pin male header in VIN, GND, GND, and +5V.  

Plug in your Arduino with your USB cable (USB-B on the Arduino UNO or earlier, and USB-microB for Arduino Leonardo) to your computer.  Download this zip file and unzip onto your computer.  If you are on a Mac, double click the folder labeled “FishBank-ArduSensor-Fart-Example-Code-f78ead3”, double-click the file named “FartRead.ino”, then press OK when the dialogue box pops up. If you are on a Windows computer, press Save instead of Open when you press the download button, double click the folder labeled “FishBank-ArduSensor-Fart-Example-Code-f78ead3”, double-click the file named “FartRead.ino,” and then press OK in the pop up box.

The Arduino IDE should open up with the ArduSensor Fart Read sketch.  This sketch prints out the reading of the methane sensor on the serial monitor.

First, make sure to select the board that you are using from Tools > Board.

Then, go into Tools > Serial Port, and select the correct COM/Serial Port.  On a Mac, the usual Serial Port will be /dev/tty.usbmodemfa131.  Any small variation of that will be fine.

On Windows, the COM Port will usually be COM 4, and anything lower or higher might work.

Here are the basic buttons/functions in the Arduino IDE:



Now let’s upload the sketch/code to the Arduino.  Plug one end of the cable into your Arduino, and then the other end into the computer.  Press the Compile + Upload button (Verify if there is any errors in the code, and then upload the sketch/code onto the Arduino), and the program will run on the Arduino.

Press the Serial Monitor button (in the upper-right hand corner), and you should see that it outputs a value from about 150 to 300.  At first, the number will be ~300, but the number should be going down slowly.  After about a minute, it should be at a stable value (maybe goes up one or two now and again, that is fine) at around 175 to 190.

If you fart, the number should go up by about 100 after ~5 seconds.  Make sure and do not touch the sensor, for it is very hot, and it will mess up the data the Arduino is receiving.

WARNING:  The methane sensor gets VERY hot after it is powered on for 1 minute or longer.  Do not touch the actual sensor while you are farting!  Make sure that after you are finished using your ArduSensor Fart, that you unplug the Arduino from the computer, or remove the ArduSensor Fart from the Arduino.  Uploading another sketch will not cool down the ArduSensor Fart, only unplugging power from it will.

Enjoy! :D

If you have any more questions on this product, contact Qtechknow Tech Support at


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