Implementing rbuttons.py

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.

Downloading rbuttons.py and test-buttons.py

If you have a non-root privilege instance of IDLE open now, close it and perform the following steps from the command line:

1. Open a new instance of the Python IDE using the sudo idle command.

2. Download rbuttons.py and test-buttons.py from the Chapter 8 folder at http://1drv.ms/1ysAxkl into your...