Arduino 433Mhz receiver / unknown Sender

Using Arduino Project Guidance
1

I'd like to get your opinion on a project that I have in mind, of which I'd like to know if it's feasable to get it working.

I have an unknown 433Mhz sender, Chinese make.
It communicates with a receiver, of which I was able to open it and have look to the IC's.

What I want to achieve is not making use of the pre-delivered receiver to switch, but with a 433Mhz receiver connected to my Arduino Uno (to pin 2). The 433Mhz receiver that I have for my arduino is the well-known XY-MK-5V receiver.

The pre-delivered receiver makes use of a 433Mhz receiver, connected to the IC Elan EM78P153SPC.
According to what I found this is a microcontroller (of which I don't have any source code)
The internal receiver seems to be a standard 433,92Mhz receiver. Codes on it are: CZS-4A SZSAW.

edit I found this on the internet about the receiver:

Working voltage?DC5V
Working frequency?315?433.92MHz
Working current?4mA
Sensitivity?-103dBm
Modulation Method?Amplitude modulation?OOK?
Working temperature? -10?~+70?
Size?34×16×7mm

My big question is, do you think it's possible to catch the 433Mhz signal on my Arduino, possibly decode it and create events based on the signal? The sender just had one event, it's a sort of NO/NC contact.

If you think this is possible, do you have any start point for me?

2

yes you can use it ,, fm modulation ,,
look for ,, GitHub - sui77/rc-switch: Arduino lib to operate 433/315Mhz devices like power outlet sockets.
this wil work whit this ,, if you know where the inputs and outputs of the signal are ,

3

alright, well my thought was that it was AM and no FM modulation (since that's also stated in the specs of the receiver).

What exactly do you mean with 'where the inputs and outputs of the signal are'?

I already played around with the RCswitch library.
Loaded the ReceiveDemo_Simple.pde in the Arduino, with the receiver connected on pin 2.

In the ' loop' I expected to see 'Unknown encoding' printed on the serial monitor, but I see nothing happening.
Or will only happen anything on the serial monitor when a signal is received?

void loop() {
  if (mySwitch.available()) {
    
    int value = mySwitch.getReceivedValue();
    
    if (value == 0) {
      Serial.print("Unknown encoding");
    } else {
      Serial.print("Received ");
      Serial.print( mySwitch.getReceivedValue() );
      Serial.print(" / ");
      Serial.print( mySwitch.getReceivedBitlength() );
      Serial.print("bit ");
      Serial.print("Protocol: ");
      Serial.println( mySwitch.getReceivedProtocol() );
    }

    mySwitch.resetAvailable();
  }

How do I know that mySwitch.available is available? Do I have a wrong assumption?

On the other hand, does this library just decode certain signals or doesn't that matter?
Is there a possibility to see the raw information coming by on the serial monitor?

4

The RC-switch library decodes only certain types of signals, and there are very many types. The usual approach to decoding RF sensors is to use a 433 MHz receiver (or other frequency, as appropriate) as input to the audio jack of a computer, and to visualize the output using the program Audacity to see the actual data bits. Google "audacity decode RF sensors" for lots of ideas, but here is one link: Reverse Engineer Wireless Temperature / Humidity / Rain Sensors — Part 1 « RAYSHOBBY.NET

5

Well that was very valuable information, thank you.
I've been reading through your link, buillt the RF sniffer circuit and recorded 3 events on the line in jack of my PC.
This is all the same type of event.

The good news is that I actually see something happening in Audacity when I trigger the event.
Though, the pattern that I see in my recording is completely different compared to the blog one.

I've uploaded the .aup here:
http://d01.megashares.com/dl/lXjGYMZ/433mhz_sensor_data.zip

If anyone would be able to help me analyze the data, that would be highly appreciated.

6

patern depents on baudrate also ,,

7

that can be seen in Audacity also, it's 44100 Hertz for this one.

8

I did some analysis on the pattern and this is my outcome:

transmission: 31x the same pattern

sync (low) between patterns is 161 samples @ 44100 Hertz
= 3,65079365079 msec

every bit is 21 samples long @ 44100 Hertz

logic 0: 8 samples high & 13 samples low = 21 samples @ 44100 Hertz
logic 1: 17 samples high & 4 low = 21 samples @ 44100 Hertz

bit pattern:

0 0 0 1 1 0 0 1 0 0 0 1 1 0 0 0 1 1 1 1 0 0 0 0 0

Now I just have to find out how I can catch this pattern on the Arduino and create an event based on this pattern.

9

Anyone who can give me a clue how to detect this signal on my 433Mhz receiver on the Arduino,
and set a LED to 'HIGH' for a few seconds when the pattern comes by?

I'm a bit stuck on how to proceed. All I find on the forum and internet is how to reproduce the signal from a transmitter connected to an Arduino. But this is not what I want...

10

This might help: http://tinkerman.eldiariblau.net/decoding-433mhz-rf-data-from-wireless-switches-the-data/

You have to figure out exactly how the signal is encoded, in order to properly decode it, and that can take some work.