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I'm trying to control a 315MHz RF socket using the RCSwitch library. I tested with an Arduino and it worked 100% of the time but when porting over to a pi zero I can only get it to correctly turn on / off about 1 in every 10-15 tries.

I'm not sure if there is a problem with my code, the library or just the pi not being fast enough to handle sending the data properly.

Here's my current code:

#include <wiringPi.h>
#include "RCSwitch.h>

int main(int argc, char** argv)
{
    wiringPiSetup();

    RCSwitch sw;
    sw.enableTransmit(0);
    sw.setProtocol(6);
    sw.send(16777173, 24);
}

edit: It definitely appears to be at least partly a performance problem, compiling with -O2 ups the success rate to around 1/3.

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  • I'm not familiar with RCSwitch so I looked it up and there appear to be a lot of different projects to bring it to the Rpi. How did you get RCSwitch? Also in general a Rpi runs a full multitasking operating system so it can't do real time things like a microcontroller. But in your case turning on and off a RF socket shouldn't be affected by that. Also I can't find anything for Protocol 6 at least in github.com/r10r/rcswitch-pi/blob/master/RCSwitch.cpp – T. M. Feb 25 '19 at 2:16
  • I'm using the "official" RCSwitch from github.com/sui77/rc-switch. – 1234123121 Feb 25 '19 at 2:31
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The problem was with how the wiringPi handles sleeping. Actual sleeps appear to not be accurate enough so a wait loop has to be used.

The solution was to change the call to the delayMicroseconds function in RCSwitch::transmit to delayMicrosecondsHard which is defined in wiringPi.c but not exported so I copied the implementation into RCSwitch.

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