Myles Long from Cult of the Dead Cow writes,
Ninja Strike Force member Lady Ada has posted a design for a self-tuning, microprocessor controlled, wide band RF jammer.
Lady Ada (who is, omg, a girl! not knitting, but hacking hardware!) explains:
This website details the design and construction [of a] Wave Bubble: a self-tuning, wide-bandwidth portable RF jammer. The device is lightweight and small for easy camoflauging: it is the size of a pack of cigarettes.
An internal lithium-ion battery provides up to 2 hours of jamming (two bands, such as cell) or 4 hours (single band, such as cordless phone, GPS, WiFi, bluetooth, etc). The battery is rechargeable via a mini-USB connector or 4mm DC jack (a common size). Alternately, 3 AAA batteries may also be used.
Link. Before you go out and use one of these things, folks — remember, RF jammers are illegal.
Here was an interesting item on Lady Ada's FAQ — could this thing be used to remotely disable roadside bombs in Iraq?
Q: I'm a member/relation in xyz military service and I would like to use these devices to protect against RF-triggered IEDs
A: While cell phone jammers are useful against some IEDs, many current designs are trigged by signal-loss. I have no more pointers, but perhaps someone in your organization with more experience can inform you of the best defences one can take against such devices.
(Thanks, Oxblood Ruffin!)