RF sniffer with microcontroller

[PersianMan]

Dear friends,
I want to read the RF messages sent by a sinple transmitter (ASK, 433MHz).
Could you help me to find a basic circuit of RF sniffer with microcontroller like AVR or PIC?
It may be coded by 2226 etc. But it has fixed code. It's very good if you help me to find the soft decoder (AVR/PIC programme) of 2226 protocol.

Best Regards

 

[edeca]

The fact it is ASK makes your life slightly easier, but you will still need to know the exact frequency. Some transmitters can be programmed to use a certain frequency from a small range around the 433Mhz band, some are set to a constant frequency.

You should be able to get some basic information by hooking a uC to a receiver and observing what comes out. I have used the PICKit2 as a basic logic analyser for this before, but a decent logic analyser would go a long way.

How much control do you have over the transmitter? Can you make it transmit when you want? Is it a black box you have no control of? Or are you trying to reverse engineer transmissions when you don't even know much about the transmitter?

Be warned that the 433Mhz band can be pretty noisy. Even with decent power supply filtering I could pickup all sorts of things with my little receiver.

I couldn't find any information about the "2226 protocol", can you elaborate?

 

[PersianMan]

Dear edeca,
Thanks for your reply.
1. Sorry, I mean protocols 2262 and 2272 as transmitter and receiver (or encoder and decoder) which is existed as chips too.
2. Just i want to read the AAAAAAAADDDD messages (address and data) for using in another device that i will design, I want to check number of bits to. I want to show the message on small LCD. If you have a more advanced circuit, It's good. The important point is that we receive a encoded message with protocol 2262 etc.

 

[edeca]

OK, so the encoder chip is documented here: https://www.electro-tech-online.com/custompdfs/2010/05/PT2262.pdf

There is some code to emulate that encoding here: mikroElektronika • View topic - manchester coding with pt2262 encoder rf transmitter (you could use this to study the protocol)

Which bit are you having trouble with? Specific questions would allow us to help you better.