So one day I was over at http://hackaday.com/ and read about a guy who used his Arduino to turn a TV on and off with one of those brainwave reading headsets. Then later on that same day I was here at Instructables and a fellow had made an office chair that twitters every time he farted. So, I got to thinking and decided to mash those two hacks into one remote that changes the TV to a random channel every time he tutes!
Plus, if you throw it in a plastic enclosure and hide it between the couch cushions, you've got a purdy dang good prank!
(As an aside, I've done some internet searching and I think this might be the first flatulent operated remote control in the history of the world... I'm happy to be an innovator.)
You asked for it, here's a short video of the remote in action.
Step 1: Parts And Sketches
Arduino (I use a Duemilanove... $30-$35 depending on where you buy it. I bought mine from Make: as part of a kit http://www.makershed.com/ProductDetails.asp?ProductCode=MSGSA which comes with a Tactile Switch. But a cheaper option might be to go to Spikenzie Labs and buy an Arduino/Switch combo from them http://www.spikenzielabs.com/Catalog/index.php?main_page=product_info&cPath=12&products_id=40 is the Arduino and the switch is linked lower)
Prototyping shield ($12.50)
1/4-Size Breadboard ($4)
(Or you could replace the ProtoShield and 1/4-Size breadboard with a solderless breadboard)
1X Working TV with,
1X Working TV remote
Part One Components:
1X 10K Ohm 1/4Watt resistor ($0.99 for a 5 pack)
1X 100 Ohm 1/4Watt resistor ($0.99 for a 5 pack)
5X 15 Ohm 1/2Watt resistors ($0.99 for a 5 pack)
1X Momentary Tactile Pushbutton Switch ($0.35)
1X 38kHz Infrared Receiver Module ($3.95)
Part Two Components:
1X CH4 Methane Sensor ($29.99)
1X Infrared LED ($1.99)
(Some of the resistors from Part One; I'll explain this in a later step)
1X Plastic Enclosure (RadioShack sells them, but I was going to use one I picked up at Fry's a while back)
1X 9V battery and battery holder
Multimeter (for calibrating your CH4 Methane Sensor)
So if you're starting from scratch you're looking at about USD$86.00. I'm guessing most folks on this site and looking at this 'Ible already have the tools, Arduino and ProtoShield which would put the cost around USD$40.00 (A $34.00 CH4 Methane Sensor/IR Receiver Parallax order and a trip to RadioShack for resistors/IR LED).
Sketches are linked on the steps that they are used in. I did my best to document and put notes into my code but I'll be happy to explain anything that isn't clear. Just ask.