The Very Patient Parking Sensor

Most parking sensors are anxious creatures. The moment you put the car into reverse they begin to beep, slowly at first and then faster and faster, until the whole car sounds like a kettle about to boil over. Drivers report that the noise makes them tense, that it gives them no real sense of distance and that it tends to reach its loudest, most hysterical pitch just as they are trying to concentrate. The Very Patient Parking Sensor takes a different view.

It stays completely silent while you manoeuvre. It does not beep at the bin, the bollard or the neighbour's hedge. It trusts you. Only when the bumper makes gentle contact with an object does it produce a single soft chime, like a hotel lift arriving, followed by a warm voice saying, there we are. A small green light on the dashboard confirms that the car has now definitely arrived.

The manufacturer describes this as mindful parking. The idea, it says, is to remove stress from the process by removing information from the process. Early users have described the experience as surprisingly peaceful for about four seconds. Several have praised the voice, which never sounds disappointed, and a few have said they now reverse far more slowly, simply to delay the moment of hearing it.

The premium model adds a range of optional features. There is a gentle touch mode, which chimes when the bumper is lightly resting against a wall and says nothing at all when it is not so light. There is a diplomatic mode, which, when parked outside somebody else's house, adds the phrase they probably will not notice. There is also a memory function, which quietly records every chime and presents a short annual summary at New Year, set to soft piano music.

The company has received a number of complaints, most of them from garden walls. It has responded by releasing a matching set of foam bumper cushions in a range of pastel colours, sold separately, and a leaflet that encourages drivers to think of each chime as a learning opportunity rather than a repair bill. Sales are described as steady, and remarkably few customers have returned for a second one.

The joke is on the real sensors, which are cleverer than their beeping suggests. Most common parking sensors are ultrasonic: small discs in the bumper send out bursts of sound too high for humans to hear and listen for the echo. The time the echo takes to come back tells the car how far away an object is, and the beeping speeds up as that time gets shorter, turning into a steady tone when you are very close.

They have real limits, though. They generally work over short distances, and very thin objects such as narrow poles, or things that sit very low to the ground, can reflect too little sound to be noticed reliably. Soft or angled surfaces can scatter the echo away from the sensor too. That is why the beeping is designed to be annoying: it is supposed to make you slow down and look. A patient sensor would be relaxing, but an impatient one is usually the reason the wall is still standing.