In the beginning, the remote controller was a technically simple device using infra-red signals to switch on/off a television set. It did not take long for more functions to be added to the handy little “box”, and it has become such an integral part of every home that few owners actually know how to operate the TV, hi-fi, air-conditioning etc without the remote control.
The first vehicular application of a “remote” provided a convenient means to operate the car locks, without having to insert a key into the door’s keyhole. Early remote locking units used a separate miniature keypad with just two buttons (lock or unlock), and it could even be retrofitted to any car. Some of these aftermarket kits also included an alarm unit with a blaring siren, plus an ignition immobiliser, as part of the package.
Those were the simpler types that relied on communication between transmitter and receiver using infra-red light. Not detectable by the human eye, infra-red (IR) light is nonetheless also an electromagnetic wave similar to any visible light.
Inside an IR transmitter, an LED (light-emitting diode) emits pulses of IR light creating a code that its paired receiver recognises as a specific command. Different pulse patterns mean different commands. The receiver converts the light pulses into electrical current and the circuitry then assigns the “power” to flow into the specific switch. Since the IR signal is actually a light beam, it cannot penetrate an opaque surface such as a wall, and it needs to be pointed in the general direction of the receiver. IR remote devices continue to be widely used for household appliances, and cheap IR kits can be bought off the shelf for customised applications, not just for DIY electronics or vehicle locks.
More sophisticated methods are now used in remote locking/unlocking systems for automobiles. The most advanced of these today operate by radio frequency (RF) transmission. Insofar as the necessity for a transmitter and receiver is concerned, how RF works is not dissimilar to the more widely used IR. However, the RF system can be designed to incorporate a wider variety of operational parameters, meaning more precise control.
As a Torque reader, surely you have driven an radio-controlled (RC) car before, and if you recall, the hand-held controller can modulate the scale model’s acceleration and steering wheel angles, consistently with no loss in precision, until the battery goes dead or the toy has gone out of range. Well, RC cars were around long before “full-scale 1:1” car manufacturers developed remote locking/unlocking based on radio signals.
Of course, current state-of-the-art electronics enable remote locking/ unlocking of the doors and boot, plus engine start/stop, without even having to touch the key. Known in the industry as “keyless entry”, it was introduced as a special keycard in 1998 by Mercedes-Benz, which coined the term Keyless-Go, because you could get in and drive off with your key in your pocket. Neither the door lock nor the ignition switch requires a key to be inserted. The external keyholes remain, of course, in case of emergencies such as when the car battery is weak.
One interesting feature of a modern “keyless” system is its ability to identify the discreet “field” outside or inside the car where the key is located. Hence, the touch sensor on the door handle will refuse to lock if the key is inside the car, and similarly refuse to activate ignition if the key is held just beyond the outline of the cabin.
Among the variety of smart “keyless” systems in use these days, some are obviously smarter than others, such as those that know you’re approaching the car and automatically turn on the interior lighting or door handle lights.
Generally, the latest generation of super-intelligent “keyless” setups still function within very finely defined parameters. All rely on radio frequency transmission and a series of hidden antennae around the car body to zero-in on the exact location of the key. More antennae give the radio signal receiver-module a higher level of precision in identifying the coordinates of the key’s position – which helps to avoid accidentally locking the car with the key on the centre console or in the boot.
Is this about as sophisticated as the car’s remote control can get? Probably not.
