And the best part is that the total parts cost is less than $1.50!! (Assuming that you already have an Arduino and the tools)
This is a contest entry for the LED Contest with Elemental LED, so if you like it, please tell your friends and rate it up! Thanks!
I know this is my first Instructable, but believe me, I have been working with electronics practically my whole life. I started up with Arduino about 6 months ago, and I've made at least 150-200 different projects, and I've also created a ton of other original things with Arduino and other microcontrollers. I even built my own computer, so you know I'm not messing around. :)
Step 1: Parts list
1x Infrared Detector ($0.78) http://goo.gl/6sSN6
1x Wide angle Infrared LED ($0.23) http://goo.gl/5PFlS
1x Narrow angle Infrared LED ($0.23) http://goo.gl/67sCf
1x 2N3904 PNP transistor (or equivalent) ($0.08) http://goo.gl/XD3jI
1x 10 Ohm resistor (Brown, Black, Black, Gold) ($0.05) http://goo.gl/UiKDs
1x 47 Ohm resistor (Yellow, Purple, Black, Gold) ($0.10) http://goo.gl/89jXQ
1x Arduino Uno (or equivalent) ($25.00) http://goo.gl/p9wVs
Some wire (preferably solid-core, 22 gauge or so) (About $7-$8 at your local hardware/electronics store)
1x USB A-B cable (for programming the Arduino) ($2.95) http://goo.gl/3f6rx
1x Soldering Iron (Optional) (About $15-$25 at your local hardware/electronics store)
1x Spool of thin solder (About $10 at your local hardware/electronics store)
1x Solderless breadboard (About $5-$6 at your local electronics store)
1x Computer (I would hope you know where to get one of these)
1x Arduino IDE (can be downloaded here)
Step 2: Wiring
1.) Plug in IR Detector. Make sure the dome on it is facing you.
2.) Connect the leftmost pin of the detector to Arduino Digital pin 2, the middle pin to Ground, and the rightmost pin to +3.3V.
3.) Plug in the 2N3904 NPN transistor. Make sure the flat side is facing you.
4.) Connect the leftmost pin of the transistor to the 47 Ohm resistor, the middle pin through the 10 Ohm resistor to Arduino Digital pin 3 (PWM), and the rightmost pin to Ground.
5.) Connect the cathodes (negative, has a shorter leg, and the side is marked with a flat part to indicate the cathode) to the other end of the 47 Ohm resistor, and the anodes (longer lead, not the cathode) to +3.3V.
Step 3: Upload the sketch!
Connect your Arduino to the computer using the USB A-B cable, then download the .ZIP file below. In the .ZIP file, there should be a folder called "TV_Annoyer". Copy this folder into your Arduino Sketchbook folder. On a Windows machine this is usually located in "C:\Users\<username>\Documents\Arduino".
Open the sketch in the Arduino IDE (downloaded from the Arduino.cc website), and upload it to the Arduino board.
If it doesn't upload right, try these troubleshooting tips:
1.) Restart the Arduino IDE.
2.) Try unplugging/replugging the Arduino into the computer.
3.) Make sure that your Arduino is properly connected to your computer.
4.) Check if your correct board is selected in the "Tools>Board" menu at the top of the IDE.
5.) Make sure the right COM port is selected in the "Tools>Port" menu at the top of the IDE. You can check which COM port your Arduino is on by (on a Windows machine) clicking the "Start" button, and searching for "Device Manager". Then click the arrow next to the "Ports (COM & LPT)" selection. Your Arduino board should be on that list, next to the COM port it is attached to.
Step 4: Use it!
Make sure that the IR LEDs are pointing at the TV and the dome on the IR Detector is facing towards the remote control.