The first module we will analyze is the
rbuttons.py file; it uses the
RPi.GPIO library to enable an LED to be driven and uses two switches to be sensed. If you remember, back in
Chapter 5, Port Input and Output on the Raspberry Pi, we told you that the use of the GPIO library functions requires root privileges. At that time, we suggested starting the Python 2 IDLE IDE using the command line
sudo idle to get the required root privileges. This got around the problem of development, and again here, you can start IDLE from the command line. We will programmatically set the required privileges when we eventually run all the programs together.
If you have a non-root privilege instance ...