433 MHz RF - Temperature and humidity sensor

Projects Discussion and Showcase Home Automation
38

New CRC findings:

  • same values of temp and HUM, different "random"
001011111100 01 011001110110 00000011 00001111 - Battery=0 Channel=1 Temperature=75.4F Humidity=48%
001011111100 01 011001110110 00000011 00001111 - Battery=0 Channel=1 Temperature=75.4F Humidity=48%
000011000100 01 011001110110 00000011 10001011 - Battery=0 Channel=1 Temperature=75.4F Humidity=48%
000011000100 01 011001110110 00000011 10001011 - Battery=0 Channel=1 Temperature=75.4F Humidity=48%
  • CRC is channel-number dependend
001010010001 01 011011110011 00100011 10010101 - Battery=1 Channel=1 Temperature=11.4F Humidity=50% CH-2
001010010001 10 011011110011 00100011 10011000 - Battery=1 Channel=2 Temperature=11.4F Humidity=50% CH-3 
001010010001 00 011011110011 00100011 00010111 - Battery=1 Channel=0 Temperature=11.4F Humidity=50% CH-1

or

001011111100 10 111101100110 00010011 00000110 - Battery=0 Channel=2 Temperature=74.7F Humidity=49% CH2
001011111100 01 111101100110 00010011 00001011 - Battery=0 Channel=1 Temperature=74.7F Humidity=49% CH1

I got almost-succesful one lucky-shot of CRC calculation, but I couldn't repeat it with others... :frowning:
I summed up values of: Random + CH-dec + tempF (the after-dot value) and HUM - the number altogether was 1-2dec different from CRC (CRC 137, value 138).

Also one strange thing - same CRC, same temp and HUM, different binary?!

001110100100 01 001001110111 00101010 00101011 - Battery=0 Channel=1 Temperature=75.0F Humidity=43%
001110100100 01 001001110110 10110010 00101011 - Battery=0 Channel=1 Temperature=75.0F Humidity=43%