Doesn't work on Raspbian JESSIE?

[arnlen]

I try to use this gem but I don't manage to control any pin.
I have no error message, but nothing happens on my board.

The LED on pin 17 is on, since the boot of the raspberry. But:

pin = PiPiper::Pin.new(:pin => 17, :direction => :out)
=> #<PiPiper::Pin:0x1ea4448 @pin=17, @direction=:out, @invert=false, @trigger=:both, @pull=0, @last_value=nil, @value=0>

pin.on
=> 1

pin.off
=> 1

pin.on?
=> false

pin.off?
=> true

Does anyone succeed to make it work on Raspbian Jessie + Ruby 2?

root@raspberrypi:~# ruby -v
ruby 2.1.5p273 (2014-11-13) [arm-linux-gnueabihf]

[zsyed91]

Haven't gotten a chance to upgrade to jessie yet so I am not sure. It seems like the changes in jessie mean you don't need sudo access for GPIO anymore. But to be safe, did you try running your script or irb session using rvmsudo?

I can take a look but AFAIK pin.on and pin.off will always return 1 if it was successful. So the "state" is correct here, when you do pin.off?. Just to clarify, is this your workflow:

1. Led @ 17 is off
2. Instantiate pin with PiPiper and do pin.on.
3. Led @ 17 is now on
4. pin.off
5. Led @ 17 is still on?

If you say that the led is already on before the script, then either your wiring is done in a way that power is always getting to the led or something else has locked the pin. In the latter case, that would definitely be a bug if it isn't throwing an error.

[elmatou]

tell us also which version of PiPiper you are using.

[arnlen]

Here is what I notice:

• connected to 3.3V pins (pin adding numbers to morse alphabet #1 or Update SPI to use the platform driver #17), the LED if on when the board is powered on.
• connected to another pin (GPIO 17 on pin Software or hardware PWM output #11), the LED is off on startup.

Then:

# same as rvmsudo but for rbenv
rbenv sudo irb

irb(main):001:0> require 'pi_piper'
=> true
irb(main):002:0> include PiPiper
=> Object

irb(main):005:0* pin = PiPiper::Pin.new(:pin => 13, :direction => :out)
=> #<PiPiper::Pin:0x5665da18 @pin=13, @direction=:out, @invert=false, @trigger=:both, @pull=0, @last_value=nil, @value=0>
# LED is off

irb(main):006:0> pin.on?
=> false

irb(main):007:0> pin.on
=> 1
# LED is still off

irb(main):008:0> pin.on?
=> false

I'm using pi_piper (2.0.0)

[arnlen]

If I try to use pi_piper without sudo:

irb(main):004:0* pin = PiPiper::Pin.new(:pin => 11, :direction => :out)

bcm2835_init: Unable to open /dev/mem: Permission denied
Errno::EACCES: Permission denied @ rb_sysopen - /sys/class/gpio/gpio11/direction
    from /home/pi/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/pi_piper-2.0.0/lib/pi_piper/bcm2835.rb:61:in `write'
    from /home/pi/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/pi_piper-2.0.0/lib/pi_piper/bcm2835.rb:61:in `pin_direction'
    from /home/pi/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/pi_piper-2.0.0/lib/pi_piper/bcm2835.rb:45:in `pin_output'
    from /home/pi/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/pi_piper-2.0.0/lib/pi_piper/pin.rb:56:in `initialize'
    from (irb):4:in `new'
    from (irb):4
    from /home/pi/.rbenv/versions/2.3.0/bin/irb:11:in `<main>'
irb(main):005:0>

[arnlen]

It works!
My bad, I was misunderstanding the pin number: I though the pin number was the number in the order of the GPIO (from 1 to 40), but in fact I understand there is no relation between the position of the pin, and its number.

The GPIO 17 pin is on the place 11, but it's still called "17".

Conclusion:

• still works on Jessie
• still requires sudo

Thanks for your help! :)

[zsyed91]

Ah yes, I was thinking that might be it. I will update the documentation to make this clearer. I noticed that others have had that same misunderstanding. I am glad that it works for you though!