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Step 1: What You Need...
I chose to use a Sony remote control (SR-P30) because it has plenty of room inside to add my circuit and a 9 volt battery while keeping the remote fully functional.
The circuit parts:
1. Small circuit board
2. (1) 10k variable resistor
3. (1) 555 Timer
4. (4) resistors. 470ohm, 1k, 560ohm
5. (2) high speed switching diodes 1N4148
6. (1) transistor - BC557
7. (2) Infrared LED's
8. (2) 10nf capacitors
9. (1) 9 volt battery
Build the circuit based on the diagram below.
Step 2: Install the Circuit...
I hot glued the circuit inside the remote control. I also had to remove 2 posts to make room for the 9 volt battery. Tape down the LED's near the existing LED. I used the existing switch on the remote and wired my 9 volt battery to it.
Step 3: Test It Out!
You may have to tinker with the 10k pot to get the frequency right for the device you are targeting. Adjust the pot while the remote is 'on' and test it with the original remote until the jammer confuses the device. Now, just pull out the remote whenever you need to take control of your device and no one will have any idea what's going on. You can bring this to a friends house and drive them nuts! Have fun, be safe!
Step 4: How Does It Work?
This is a pretty simple concept. When you press a button on a remote crontrol for a TV, stereo or other IR device, it creates a series of pulses which the receiver in the target device; in this example, a TV, decodes into the corresponding function. This frequency is around 35-40kHz. To confuse the receiver, this jammer sends out a steady stream of binary code (1's an 0's) at the same frequency, but contains no information to decode. The receiver basically sits there and does not respond at all and the real information cannot get through to it as long as the jammer is on. Voila! You've 'jammed' your TV remote!