I am interested in a way of how to open the caar's doors with a microcontroller device's extension hardware (I have an Arduino Uno Rev 3).
I know that the key can do it as well but I want to program things. The frequency of the signal is 433.92 MHz and the modulation is FM and AM. Therefore I need a device (a hardware that can be connected to the microcontroller) that can emmit/send and receive signals with this certain wave's frequency.
It is to be mentioned that, for me, it is not the most important thing to finally get to open the vehicle (the central locking system) but to work with it and to do experiments and to read what the key sends (this is actually the most important thing).
Can you recommend a hardware that can read 433 MHz signals ?
Are there differences among them?
I want to express my interest into that I want to receive the signal that is sent by the remote key.
(edit)
Later on, I can try to get some useful data out of the signal.
But, for the beginning, where do I know that all the remote keys work with the same method (I refer to this Wikipedia article: method of modulation). And this is what I meant with FM (frequency modulation) as an example.
By the way, ATA5811 sounds really good – I read the data sheet and it can use both ASK and FSK (modulation). How can I find out, what my car key uses (there are so many paramters!) ?
Best Answer
I think the radio part is the least of your problems. To my best knowledge most car openers use a cryoptographic system called "rolling keys", which means that recording what the keyfob sent and replaying it won't work. Microchip has extensive libraries to go with thier chips intende for this purpose, but you need to sign a non-disclosure to get it. Here is a (probably simplified) explanation.