How Does Keyless Entry for Cars Work?

A keyless entry key fob sends a signal to a receiver in the dashboard.

While the technology appeared in the 1980s, the keyless entry systems of today have been adapted to provide the utmost security. Some can remotely start the car or turn off the engine in the event of theft.

Parts

The keyless entry system contains a keychain fob and a receiver in the dashboard. The keychain fob houses the remote control unit, which is composed of an integrated circuit and radio transmitter.

Communication

The remote control unit creates a unique code for the chosen function every time a button is pressed. A receiver on the same frequency receives the signal, and if the code is not what the receiver expects, it will not complete the function. The ever-changing codes are meant to prevent thieves from capturing the codes.

Function

When a key fob button is pressed, the underlying metallic pad presses down on circuit board wires. The remote control unit creates the code and sends a signal to the receiver. If the code is accepted, the receiver sends a signal to the processor to signify which action should be performed. The processor may make noise, such as sounding the horn, to signify the action is complete.

References

• New York Times: How It Works