This is a project that I originally started many years ago. I tried to build the oscillator according to Aaron Cake's schematic, but since I didn't know much about electronics when I started this project, I gave up because I couldn't get it to work. I tried to build a 555 timer version of a jammer, and that didn't work out too well either. I was able to get a 38kHz frequency going, but it would not jam my remotes. I scrapped that idea even after I had completely written the tutorial to build it. The upside of a 555 is that it is easily programmed with discrete components. Anyone can do that in their own home without expensive compilers.
Some folks have said in other forums that the IR jammer is banned by the FCC. If that were the case, the FCC wouldn't even allow you to use a flashlight without obtaining a license. And if you have a tv that was ruined by a stream of IR flashes, I really want to see it duplicated. For the purposes of jamming your own television this circuit is completely legal. Uses other than messing with your own home equipment may or may not be legal. If you use this on a Sony device, you'll probably be sued.
I built my circuit on a one-sided printed circuit board. Using perfboard or any other prototyping board is completely acceptable. Just be sure to use an IC socket so that you can remove your chip and reprogram it later if you decide to change something. If you decide to use perfboard, follow the schematic and mark off the connections as you make them. If you prefer to make a circuit board, the mask is included in the PDF file below.
The initial test was limited to 6 feet from the television because of the programming cable length. I used USB power and the Pickit2 programmer to test this circuit. It worked with both 45 degree and 18 degree LEDs. [The 45 degree is from Radio Shack and the 18 degree is from Digikey.] I plan on using one 18 degree and two 45 degree IR LEDs.
You can see the four frequencies in the Fast Fourier Transform that I did on my Tektronix oscilloscope. I have 33kHz, 38kHz, 43kHz, and 48kHz. Those are rounded off numbers. The instructions were running at an average of .9uS per instruction. The estimated rate was 1uS each, so the programs ran a little faster than expected. This is ok because the receivers have a range of plus or minus a few kilohertz. They operate like a bandpass filter, so you won't need exact frequencies to get it to work.
###The actual breadboard/assembly steps are excluded, with the exception of the Fritz. I usually do not include step-by-step circuit assembly instructions since I believe that reading a schematic gives you creative flexibility. Everything is flexible in this project. You could choose to use two AA batteries or you could regulate a 9V. You can modify the circuit to use transistors to boost the power to the LEDs. You can use a bigger box, a smaller box, or just use no box at all. Finally, you have access to my programming files so you can change it and make your own. This is how I made mine. Your mileage may vary (YMMV).
###The PCB mounting holes in the 5"x2"x2.5" Shack project box are about 1.8" apart. I cut two square notches out of the PCB board to extend through the lid screw holes. This gives me a little more room in my box. Then I marked where the holes should go. I suggest drilling your circuit board before continuing to step 3 since the circuit board might break, especially if you use perf board. (Check out my PCB mask to see how I designed it to fit in the box. I did have to file the holes towards the center of the pcb since the mounting holes in the box are a little less than 1.8" apart.)
[I gave up on the 555 timer circuit, but the pictures were good. I used the same project box for the microcontroller version.]
