Circuit Playground Express Remote-Controlled Fart Machine

I’m not proud of this, but I made it so you won’t have to:

Craig at Elmwood Electronics very kindly gave me an ADABOX 006. It’s based around Adafruit’s Circuit Playground Express which just happens to feature a small built-in speaker, IR remote control and the ability to play back audio samples. You see where this is going, don’t you?

If you must make this, the code and samples are here: You’ll also need to install the Adafruit CircuitPython IRRemote package into the lib/ folder of your Circuit Playground Express. Point the remote at the board, and it’s left arrow to fart, right arrow to chuckle.

The package includes CC0-licensed samples downloaded from Freesound.

USB Fart Detector (unfortunately)

It is a truth universally acknowledged, that an engineer in possession of a solid-state flammable gas detector, will shortly make a fart detector with it. I’m sorry, but call it childishness, simple-minded curiosity, or the results of a diet high in polysaccharides, but this is something I have to get out of my system. (It’s okay; I’ll waft the door.)

This all started when our carbon monoxide detector decided it was past its best, and started to emit an ear-splitting shriek. Thinking there might be some cool parts inside, I took it apart. Inside, in amongst the other stuff, I found this:

gas sensor boardThankfully, David Cook of Robot Room had once had the same idea as me (well, minus the puerile bits), and he documented the sensor board very well: Explosive Gas Detector Board. Here are the four pins that you really need to get the thing going:

 Pin # (from left)    Function
===================  ==========
       1              Vcc
       2              /Enable
       3              /Gas
       5              Gnd

Pins 2 and 3 are active low signals. To be typographically correct, I’d write them as Enable and Gas, but that’s hard to do in fixed-pitch ASCII. I can understand why the Gas signal should be active low (think about it; if the Figaro TGS 2611 sensor fails or shorts, it will likely fail to an alarm state, so you’ll still be alive to curse the bloody noise that woke you at 03h00), but the Enable being active low? Dunno.

I was hoping to have presented a little sketch for the Digispark that would have typed something unhelpful every time that gas was detected, but it was not to be. It seems that Macs and Digispark keyboard emulation is a thing of great wobbliness, so I had to resort to an Arduino and a serial connection.

Here’s the code:

 gas_detector - uses board scavenged from CO detector
 scruss - 2013-02-18 (unfortunately)

int gas     = 2;               // /Gas line on pin 2
int val     = 0;
int lastval = 0;

void setup() {                
  pinMode(gas, INPUT);

void loop() {
  val = digitalRead(gas);
  if (val != lastval) {
    if (val == LOW) {          // LOW means gas detected
      delay(1000);             // wait 1s for air to clear
  lastval = val;

Before you ask, I tested the circuit by briefly hitting the button on a gas lighter. Honest.

I’ll keep working on the Digispark; it’s such a nifty little device, and this is such a worthy project …

on avon

We’re in Stratford. It’s real purty.

There’s a lot of local opposition to putting a Wal*Mart here. Putting a wal*mart in Stratford would be like putting a fart gag in Hamlet.