Another update to wiringPi

Thanks to Keith Wright for diligently testing it and pointing out bugs for me – fixed some issues in the gpio command, and while I was at it, I added in 2 new functions to it to allow for easy exporting/unexporting of the /sys/class/gpio interface – so now you can write a little script to do the exports for you, then run your own program that uses that interface (e.g.) a Python, shell, or php script, then un-export them afterwards, all without needing to be root (or use the sudo command)


Another update to wiringPi — 7 Comments

  1. Hi Gordon
    I’m a novice and I’m all fired up with enthusiasm for the RasPi, and your projects so far have made it a great experience. I actually managed to get the Pelican Crossing project working. I am also learning Python, so it would be really good if you showed us how to write that program in Python. Keep up the good work and kind regards

    • Hi,
      Glad you’r enjoying it so-far.
      However.. I’m not a Python programmer… I’ve written (actually modified) just one Python program in my whole life. Everything I do these days is in C or BASIC (or php, sometimes perl & shell).
      There is a Python wrapper for wiringPi though, so I might have a look at it all sometime – you never know!


  2. Hi again Gordon
    I have managed to get a Python version working, and the listing is below. It uses RPi.GPIO. Compared with your shell version ( my version uses a lot of CPU while waiting for the button to be pressed. Maybe some of your readers will have suggestions for improving this code.

    #Python program for operating the Pelican Crossing breadboard circuit by
    # Kieran Cranley. 1-Aug-12

    from time import sleep
    import RPi.GPIO as GPIO
    # **NB these are NOT wiringPi pin nos!**
    GPIO.setup (3, GPIO.IN) # button switch Pin #3
    GPIO.setup (11, GPIO.OUT) # red LED Pin #11
    GPIO.setup (12, GPIO.OUT) # amber LED Pin #12
    GPIO.setup (13, GPIO.OUT) # green LED Pin #13
    GPIO.setup (15, GPIO.OUT) # redman LED Pin #15
    GPIO.setup (16, GPIO.OUT) # greenman LED Pin #16

    print “Waiting for button…”

    def waitButton():
    if GPIO.input(3):
    GPIO.output(13, True) # green LED ON
    GPIO.output(11, False) # red LED OFF
    GPIO.output(15, True) # redman LED ON
    print ” Button has been pressed”
    GPIO.output(13, False) # green LED OFF
    GPIO.output(12, True) # amber LED ON
    GPIO.output(12, False) # amber LED OFF
    GPIO.output(11, True) # red LED ON

    def stopTraffic():
    print ” Stop traffic”
    GPIO.output (13, False) # green LED OFF
    GPIO.output (15, False) # redman LED OFF
    GPIO.output (11, True) # red LED ON

    def walk():
    print ” Walk”
    GPIO.output (15, False) # redman LED OFF
    GPIO.output (16, True) # greenman LED ON

    def graceTime():
    print ” Flashing”
    GPIO.output (11, False) # red LED OFF

    for i in range (1, 8):
    GPIO.output (16, False) # greenman LED OFF
    GPIO.output (12, False) # amber LED OFF
    GPIO.output (12, True) # amber LED ON
    GPIO.output (16, True) # greenman LED ON
    GPIO.output (16, False) # greenman LED OFF
    GPIO.output (12, False) # amber LED OFF

    def startTraffic():
    print ” Don’t walk!”
    GPIO.output (15, True) # redman LED ON
    GPIO.output (13, True) # green LED ON
    print “\nWaiting for button…”

    while 1:

    ”’def main(): # The program works
    return 0 # whether this code
    # is included or not
    if __name__ == ‘__main__’:

    • That’s great!

      I suspect your comment isn’t going to come out indented the way Python likes it though – I’ll blame this theme I’m using in WordPress….

      Basically, I do a sleep 0.1 in my shell script while waiting on the button – it does mean that a very brief stab at the button might be missed though, but it reduces CPU usage down… It’s not a perfect way of doing it, but it mostly works!


  3. OK Gordon – now that I’ve got this running with RPi.GPIO, using

    import RPi.GPIO as GPIO
    GPIO.setup (3, GPIO.IN)
    GPIO.setup (11, GPIO.OUT) etc etc

    what do I need to replace these with to use wiringPi?

    • what I’d suggest is this:

      Use the gpio command to setup the pins – like:

      gpio export 3 in
      gpio export 11 out


      then in your python script, remove (or comment out) the GPIO.setup statements, then you should be able to run your program without using sudo.

      wiringPi and the existing RPi.GPIO library are essentially doing the same thing, but you can use the gpio command that comes with wiringPi as an easy way to initialise the GPIO pins + direction without the need to be root, or use sudo.