This little device is wonderful, for parties at least. Accuracy wise, it’s not much more than a toy (without some opamps for signal amplification and filtering) but I digress. Just plugged right straight into an Arduino will be plenty of fun, assuming you read the datasheet.
The image is fairly self explanatory. Give the heater +1VDC (PWM with analogWrite(heaterPwrPin, 51) attached to base of 2n3906 or any PNP transistor, +5VDC to collector and emitter to the heater,) have the output (pin 2) attached to an analog in, and don’t forget to have a resistor between analog in and +5VDC. Oh, and make sure all grounds are connected together. For best results, use something between 5k and 20k, my test sensor loves a 16k. The lower the resistor value, the smaller the range of ethanol (alcohol) the sensor will respond to from its’ minimum to maximum.
Furthermore, for a semblance of accuracy (but quite non mandatory, see below,) it requires a burn in period of 48 hours at 2.2VDC. Its going to draw around 120mA of current, so make sure your power source can handle the load. I powered mine on a breadboard connected to my USB power bus (thanks Teensy!) I would also suggest oversampling and averaging, for a little extra boost in accuracy once you’ve got it burned in.
The datasheet for this item is pretty marred by the curse of Engrish, but I’ve been successful with the setup here, found on various forums and on irc. If you’ve tried something different or had different results, let me know. That’s what comments are for!