Farley Rusks, who zapped the witch in the "New Classic Fun" chapter, proudly boasts that setting off other peoples' radar detectors is absolutely the best trick he's ever invented!  Farley used his engineering expertise to build his own radar gun.  A modern (super-heterodyne) radar detector contains a "local oscillator" that generates a few milliwatts of microwaves.  Farley's radar phaser pistol works by enhancing that effect.  He bought a used radar detector is pieces and retuned the local oscillator to the police radar-gun frequency.

    Farley is a genuinely creative individual, so he didn't stop there.  He bought a toy plastic space pistol for 50 cents at a garage sale, and installed the whole thing inside it!  He then added a 9-volt battery and a piezo-electric noisemaker from Radio Shack.  The device will trigger other peoples' "fuzzbusters" up to a quarter mile away, even if they are pointed in the opposite direction.  It will not interfere with real police radar, since it is merely an enhanced radar detector.  It is no different in principle to the burglar alarms or automatic door openers that also set off radar detectors.  (Hint!)  Nonetheless, the authorities would surely not smile upon this freelance engineering hack.

    Farley named it "Ronald" because all ray guns are named Ronald, just as all pythons are named Monty.  Farleys says he likes to think of it as a vector-subtraction device -- if the speedster with the radar detector is ahead, it sucks him backward; if he's behind, it pushes him away.  Besides providing an interesting diversion on long trips, it has genuinely practical applications in opening up gaps in traffic and harmlessly persuading reckless drivers to moderate their speed.