How Do Remote Controls Work?

The remote control key is a wireless remote control function of the central control lock, which can be used to remotely open and lock the door without inserting the key key into the lock hole.

Chinese name: remote key
the way: Wireless remote control for center lock
Advantages: Unlock and lock remotely anytime, anywhere

Realize: Car unlocking (door opening) and locking (door locking)
Principle: The antenna receives the radio signal
component: Transmitter and receiver

A Brief History of Remote Key Development

First generation: Traditional mechanical keys implement basic door opening and closing functions.

The second generation: the door can be opened and closed by pressing the remote control button lightly, but a mechanical key is needed to start the car. The two keys are used together. One is indispensable and a bit tedious.

The third generation: the functions of the key and the remote control are combined into one, and the door opening / closing / car starting is completed by the active button. The mechanical key is embedded in the remote control key, which is ready for use.

The fourth generation: On the basis of active keystrokes, a passive working method is added, which enables door opening / closing actions without pressing keys, further improving efficiency and greatly improving safety performance. ^[1]

How the remote key works

The working principle is simple: firstly, a weak electric wave is sent from the key, the electric wave signal is received by the car antenna, the signal code is identified by the electronic control unit (ECU, Electronic Control Unit), and then the actuator (motor or electromagnetic coil) of the system Perform open / close action.

Basic composition of remote control key

The system is mainly composed of a transmitter and a receiver.

Transmitter: It consists of a transmitting switch, a transmitting antenna (keyboard), and an integrated circuit. It contains an identification code storage circuit and an AM modulation circuit, and a button-type lithium battery is installed on the opposite side of the circuit. The transmitting frequency is selected according to the radio standard of the country of use, and the transmitting switch sends a signal every time the button is pressed.

Receiver: After the transmitter sends an identification code using short-wave modulation, it receives it through the short-wave antenna of the car, and uses the distributor to enter the receiver s electronic control unit's short-wave high-frequency amplifier processor to demodulate the identification code Compare them; if the code is correct, enter the control circuit and make the actuator work.

Remote key operation

According to its use method, it can be divided into three categories: active working mode, passive working mode and coil induction mode.

Remote key active working mode

The principle is to control the door through the body electronic module (ECU, Electronic Control Unit) and the body control module (BCM, Body Control Management), just press the key button to send the unlock / lock command, and after the body electronic module is verified, it can be opened / Close the door

Remote key coil induction working mode

Mainly by placing the encrypted chip in the key, during the unlocking process, the radio frequency transceiver of the vehicle body is used to verify whether the key matches to determine whether the engine can be started. It is mainly used in special cases where the key is dead and the car can still start normally.

Remote key passive working mode

When the owner enters the sensing area of the key system, as long as he touches the door handle, the identification key "carrying" will receive the low frequency signal sent by the car. If this signal is consistent with the identification information stored in the "key", The "key" will be woken up. After the "key" is awakened, the authentication password issued by the car will be analyzed and corresponding signals will be sent. These signals are encrypted to improve security. The car will compare the received signal with the information stored inside the car. If the verification is passed, the car will unlock the door. Once the driver enters the car, simply press the start button and the car engine will start. When the button is triggered, the PKE system first needs to detect whether the "key" device is in the car, and then start the engine after completing the same certification process. When the driver leaves the car, he only needs to press the door handle, and the car door will be locked. Before the car is actually locked, the driver's position must also be detected and the same verification process must be performed. ^[2]

Passive mode