Car owners guide to: Car Accessories > Parking Sensors
 Dents
to the bumpers or underbody panels can happen all too easily when
parking in unfamiliar places, thanks to low walls and bollards.
Far worse is the chance of a child stepping out behind you to cross
the road as you are about to reverse. Parking sensors make driving
both easier and safer.
Sensors are mounted at the front and rear of the vehicle and these
gauge the proximity of objects and give out an audible warning as
you drive closer to them. These are now appearing as a factory-fitted
item on some vehicles but are also available as an aftermarket fitment.
Not only do they make parking less stressful and safer, they could
pay for themselves in a short time. The excess on your vehicle insurance
usually means you'll end up paying the full cost of any relatively
minor damage, or it could mean the loss of no claims bonus or a
personal injury claim.
Few of us might admit that we feel uncomfortable having to park
in tight spaces. A set of parking sensors won't correct bad technique
but will help to make the average driver more confident, and the
reduction in stress level alone makes it worthwhile!
Ultrasonic or Electromagnetic
There are generally two types of sensors - Ultrasonic and Electromagnetic
Systems.
Ultrasonic sensors emit a signal that gets reflected back off any
nearby obstacles. The closer the sensor gets to the object, the
quicker the reflected signal reaches the sensor. A circuit is activated
to give an audible warning, usually a similarly quickening beat.
Electromagnetic systems work by creating an electromagnetic field
in the vicinity of the sensors. Any object that intrudes into this
invisible 'force field' triggers a warning.
The Ultrasonic type is far more common but the Electromagnetic
systems offer a preferred alternative in some situations.
With Ultrasonics, it is necessary for the sensor to have clear
vision, which usually means that tiny holes must be drilled in the
bumper.
Electromagnetic systems do not look for a reflected signal, instead
they create a wide electromagnetic force-field and this can extend
through and beyond the car's body panels. For this reason, this
type of sensor can be fitted behind the bumper so that no externally
visible alteration is required, although the bumper and/or underbody
panel will need to be removed in order to fit the system.
This type of parking sensor system is also useful for vehicles
with externally mounted wheels or accessories - a spare wheel on
the back of a 4x4, for example, or a cycle rack. These can cause
false triggering or inaccurate warnings when used with ultrasonic
systems. Electromagnetic systems ignore fixed items that are already
present and look for changes to the surrounding area.
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