Most infrared remote controls operate at 40 khz. This circuit transmits a simple 40 khz squarewave. If done properly, it will effectively disable common household infrared remote controls.
Construction Notes:
- Multiple IR LEDs may be connected in parallel for more power output. This may be necessary for expensive Japanese equipment.
- Adjust the 10kΩ resistor until the frequency is just right and everything works. Alternatively, a frequency counter may be used. Then again, if you know what a frequency counter is and know how to use one, you can probably build this from a crystal and a gate.
- For maximum effectiveness, spend a lot of money on a high-capacity lithium battery, replace the push button switch with a toggle switch, and hide in a clever place.
|
|/|
+---------+------------+--| |------/\/\----+
| +--+ | |\| 50Ω 1/4W |
| | \ | | |
| +->/ 10kΩ 1/4W | IR LED |
\ \ Adjustable | |
100kΩ 1/4W / 2N4403 / | |
\ ---+ | +--------+
/ |/_ | | 1μF | |
| |/ | | + --- + -----
+---| PNP | / /-\ ---
| |\ | |/ 2N4401 | 4.5V -----
\ \---|---/\/\---| NPN | ---
150kΩ 1/4W / | 1kΩ 1/4W |\ | |
\ | _\| | |
/ --- | | |
| --- 10nF | | o |
| | | | --- |
+---------+------------+----------+--- ----+