Remote Car Key

Remote car key is present in everyone hand today,but many of us don't know electronics in it,lets know today.

Remote key means it's a entry system to car without using mechanical key support.Remote key has short-range radio transmitter,which works for certain range which is 5 - 20 meters.when key is pressed it sends coded signal through radio waves to the receiver in the car so that lock or unlock of the car door happens. 

car has sensors to detect fob, for opening of door ,truck and opening of vehicle. 

Few standard frequency.

315 MHz for North America made cars

433.92 MHz for European,Japan,Asian cars.

how to avoid duplicate key is made used in car.

we can make use of Transponder key to find the duplicate key used to ON the ignition.Transponder key have small computer chip inside them,when it's used to on the ignition it will send some code to ignition ,it will respond back if its original key by electronic control unit.this invention happens during world war 2,to find friendly planes on radar.

Rolling code

Remote car key will produce different code in order,Both in Transmitter and Receiver end,So thief cant decode the real code of remote car key,If receiver misses any signal it compares with upcoming 256 codes to match.

The transmitter controller chip has a memory which stores 40 bit code along with function code,when we press Fob 40 bit code is transmitted and receiver decode 40 bit code.

If we don't use rolling code easy to decode the code.

Hacking of system

Using house Wi - Fi ,same frequency device or using Jammer Thief try to hack your system.try to be careful about this.

Microchip

microchip HCS301 one of chip used in remote key.

34 bits not encrypted : 28 bit serial number,4 bits button information, 2 bits status(Repeat and low battery indication)

32 bits encrypted(rolling code),4 bits of button information. 

Few pictures for reference

Car Key

Remote

Future:

If we are far from car also we should know the status of the car,like that remote system will be designed.

For example:

somebody entering the car.

alarm system status.

location of car.