Help needed to decode RF sensor data

Other Hardware Sensors
1

Hi forum

Can any body help med decode 433 rf data from a temperature sensor?

I get these readouts:
22.0C -> 001000000001010011000
22.1C -> 001000100010010000000
22.2C -> 001000010010010010000
22.3C -> 001000100010010000100
22.4C -> 001000001010010010100
22.5C -> 001000110100100000100
22.6C -> 001000010010010010100
22.7C -> 001000100010010001100
22.8C -> 001100001100100011110
27.8C -> 001000000100010000000

2

In the U.S., the National Security Agency probably knows the answer.

3

Why only in the US?

4

tjntjn:
Can any body help med decode 433 rf data from a temperature sensor?

I get these readouts:

  1. Your readings appear to be 20-bit values. How did you get them?

  2. When the temperature changes from e.g. 22.0 to 22.1C, does the readout change directly between the 2 codes you listed, or are there other codes at intermediate temperatures?

5

  1. I got the values of the pin out from a 433 MHz receiver connected to my Arduino. After the intital communication, which I have not listed.. 0 = short "bit" 1 = long "bit". The same signal is transmitted twice. But I have only listed one.

  2. The readout in temperature is the what is read from the "original" commercial receiver. This is my reference.

But how do I convert the bits to temperature?

6

If you search the web with keywords like "decode rf temperature sensor" you will find lots of ideas. However, there are some cases where no one has been able to figure out the coding for the temperature or other data, and the manufacturers probably won't tell you how to do it.

What are the make and model numbers of your temperature sensor and the display unit?

7

tjntjn:

  1. I got the values of the pin out from a 433 MHz receiver connected to my Arduino. After the intital communication, which I have not listed.. 0 = short "bit" 1 = long "bit". The same signal is transmitted twice. But I have only listed one.

  2. The readout in temperature is the what is read from the "original" commercial receiver. This is my reference.

But how do I convert the bits to temperature?

You haven't answered my question #2. The sensor may be transmitting to a resolution of better than 0.1 degC, and the receiver rounding or truncating to the nearest 0.1C.

8

I think that DC42 is asking for more data. When the displayed temperature changes from 22.0 to 22.1 degrees, several bits change in the message. So either there are more temperature values between 22.0 and 22.1, or there is a checksum or CRC code in the message that changes as well. It would be very useful to have message values corresponding to 2.0 C, 1.0 C, 0.0 C, -1.0 C etc.

You hinted that only a select portion of each message was quoted in your first post, so it would also be good to reproduce several examples of the entire message.

Here is a fun story about decoding LaCrosse weather station data: TX29 Protocol