Ok, I have passive keyless entry car alarm. It showed instability from the first time I installed it (sometimes it would stop responding to remote, PKE was not working, remote start is not working.
And then it seems that after sitting for some time the power mosfets that feed the antennas for RFID were all toast. So , I was thinking to use remote from the alarm and implement my own car end of the deal.
I am quite noob with arduino, but have some experience in programming. I have allready programmed the button start/stop part of the implementation. It will also get the rpm from the engine so it will crank the engine only until engine actually runs. This works all good. Now to the complicated part to me:
The receiver module on the alarm box. I'm kinda hoping to use the module on the board and read the codes using arduino.
Do I undesrstand correctly that it outputs not serial data, but OOK encoded data and I need to decode it to make sence of it (Page 7 on datasheet)?
Also manual states that it's 433.92Mhz reciever, but datasheet says that you should have:
FREF OSC = FRF/(32 + 1.1/12)
For 433.92 MHz, FREF OSC = 13.52127 MHz.
But it has 12Mhz OSC, so frequency would be 395Mhz according to that.
There is a table on the back on the module which has 3 frequencies marked - 315, 433.92, 447.92 mhz . But in factory they havent marked which model current one is.
This gets me really confused on what frequency it runs. Nevertheless this is not importan right now.
About the bandwidth of the communication: the bandwidth seems to be lowest one (sel0 and sel1 is grounded).
Datasheet:
Pictures of alarm board:
Anyones with experience with rfid / wireless transmission would be greatly appreciated.