How can I listen for 433MHz signals in the backgrounds from boot on?

I am using this receiver / transmitter pair here.

An Arduino sends signals to the Raspberry Pi and I want to listen for them in the background. I tried the examples included in 433Utils but they use the CPU to like 98% and that's not an option. Are there any other ways?

  • 1
    What signals are being sent and how often? Are the messages formatted with any protocol?
    – joan
    Jul 30, 2015 at 17:34
  • I honestly don't know. I send messages from the arduino using the VirtualWire library, which handles that for me. Also I plan to send some short strings
    – qwertz
    Jul 30, 2015 at 17:35

1 Answer 1


There is a Virtual Wire module in the Python examples for my pigpio library.

Have a look and see if it can read your Arduino messages.

It should use a lot less than 98% CPU.

If it still uses too much I did do a quick port to C which uses a lot less CPU but I have not bothered to post that to the examples.


This raspberry Pi forum post gives an indication of the performance you may get with C rather than Python. It also gives the code I used.

It's static which is the real killer. The software has to process and discard all the false edges while waiting for a real message. With Python this might take 50%+ of CPU, with the C implementation it seemed to take 10%.

  • I will definitely check that out, thanks! I do not own an arduino yet, but wanted to make sure I can start as soon as I get it without having to google for problems :) I will report back asap!
    – qwertz
    Jul 30, 2015 at 17:44
  • Would you be able to give me an average estimation of how much cpu it would use without C and using C?
    – qwertz
    Jul 31, 2015 at 7:35
  • @qwertz I added some information to the post.
    – joan
    Jul 31, 2015 at 9:14
  • Thank you very much! 10% seems to be perfect, I can luve with that number just fine I hope. I will try is asap when I get the receiver :)
    – qwertz
    Jul 31, 2015 at 10:35
  • So I got my parts now, but do not have any idea of how to use your code. Could you provide some info about that?
    – qwertz
    Aug 8, 2015 at 15:57

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