Re: How to take apart a key fob without destroying it!
I just wanted to know what was done initially before I gave a stab at a solution.
I think the following is how the system works in principal, probably all wrong but let me know where I am misinformed.
I think you need a chip that sends a signal of a VIN code to the SKREEM module via the halo. The VIN numbers stored in the fob chip and the SKREEM module must match. The halo excites the chip to send the VIN signal. This exchange of information takes place when the key is in the ignition and turned to at least the ON position. If the physical key cannot turn the lock tumblers then no interaction can take place.
The door lock synchronization is done in the ON position, meaning the key can turn the lock tumblers and as long as the fobs chip VIN matches the SKREEM VIN, the SKREEM will learn the fob code from the code transmitted by the fob.
The board in the fob is a transmitter only, the chip sends a signal when it is excited by the signal from the halo but the system will only function properly if the VIN codes of the SKREEM and fob chip match.
The chip is a passive component and needs external stimulation. batteries in the fob only power the door OPEN/CLOSE transmissions and are not needed to start the car.
The door OPEN/CLOSE signals use a rolling code technology, meaning the signal is not consistent.