Cab driver earns pin money on the radio tunes in to radio for pin money Yellow cab driver picks up pin money fare-jacker Taken for a ride in a hi-fare yellow cab

Been in a New York taxi recently and wondered about the high fare? Did the driver seem strangely busy cranking the window or fiddling with his radio? Chances are you were taken for a ride. For months, it seems, one yellow-cab driver with a special talent for DIY electronics has been offering his colleagues an ingenious way to rig their meters with the help of a pin and a couple of wires. His profitable sideline is no more, after his arrest earlier this week.

The victims of the scam tended to be foreign tourists and the best opportunity was on drives from Manhattan back to the airport. Once rigged, the meters could be made to read at least double the standard fare.

Mohammad Ahmed, now under arrest and charged with fraud, allegedly used to linger in the early hours outside the Hilton hotel on the Avenue of the Americas and offer his services to the drivers waiting there for the breakfast business. Police say he habitually charged about $75 (pounds 48) for each job.

Most ingenious about the racket, however, was the design of the apparatus, called a "zapper". With his pins, wires and a little wheel, Mr Ahmed apparently could connect the volume knob on a cab radio to a hidden CB radio, which when activated could make the reading on the meter suddenly zoom up.

Thus equipped, the drivers only had to decide which passengers were likely to be sufficiently unfamiliar with the normal fare rates. Most commonly it was a twist of the volume knob that did the trick. Police suspect that in some instances, the zappers were connected to other parts in the cars, like the horn or the window winder.

Investigators believe that Mr Mohammed may have altered 250 of New York's cabs. For a second fee, he would offer to temporarily remove the zapper ahead of each cab's regular police inspection.

"This guy is a meter-tampering factory. I've never even heard of anything like this before," Eugene Rodriguez of the city's Taxi and Limousine Commission, said.