danpopp.net/blog/ Fresh Coffee and Fresh Code

The remote control helicopter wars at the office have been gradually escalating over the past 4-6 weeks, reaching a critical level. Counter-measures have become increasingly more important following last week’s introduction of projectile firing capabilities by the enemy. So my team and I have taken defensive measures, part of which include erecting a veritable no-fly zone on this side of the office. To accomplish this, I have exploited a vulnerability in the enemy’s communications systems which depend on direct line-of-sight infrared communication to send commands from the pilot’s remote control to the enemy vehicles. Here is a picture of the assembled device (which works quite well):

At the core of our aerial defense is a PIC12F675 microcontroller, which has been programmed to reproduce the 6 popular IR frequencies, 30kHz, 33kHz, 36kHz, 38kHz, 40kHz and 56kHz. When the system is engaged two transistors are used to pump infrared data out of 4 IR LEDs mounted on top of the jammer, effectively interrupting enemy communication and causing their choppers to come crashing to the ground. In order maximize range and effectiveness, a pair of 10ohm resistors were substituted in place of the normal 20 or 30ohm components to increase the power output of the unit. Further measures may become necessary as the inevitable cat and mouse game evolves, and the enemy changes tactics; but for now, all is quiet on the western front.