Page 95 - Programming the Raspberry Pi Getting Started with Python

Figure 9-5 A Gertboard expansion board for the Pi
The Gertboard is really the kitchen sink of expansion boards. Its key features are as follows:
• Strapping area where GPIO pins can be connected to different modules
• ATmega (like the Arduino) microcontroller
• SPI analog-to-digital and digital-to-analog converters

• Motor controller (like the RaspiRobotBoard)
• 500mA open collector outputs (like the Pi Face)
• Twelve LEDs and three push buttons
Prototyping Boards
Unlike expansion boards, prototyping boards mostly require the use of a soldering iron and a certain
amount of electronics expertise. They also connect directly to the Raspberry Pi’s main chip, which

means that if you get it wrong, you could easily damage your Raspberry Pi. These boards are for the
experienced electronics enthusiast—or the very careful or the very reckless (who doesn’t mind the
possibility of killing their Raspberry Pi).
One of these prototyping boards, the “Cobbler,” is not actually a board but rather a connector that
allows you to link the GPIO connections to a solderless breadboard where you can add your own
electronics. As a contrast to the expansion board approach, we will explore this method further in the
next chapter using the Cobbler.
Pi Cobbler
The Pi Cobbler from Adafruit (www.adafruit.com/products/914) comes as a kit that must be soldered
together. The soldering is pretty straightforward, and once everything is assembled, you will have a
board with 26 pins coming out of the bottom that can be attached to a solderless breadboard (see
Figure 9-6). On top of the board is a 26-pin socket to which a 26-way ribbon cable lead (also supplied)
can be used to link the Raspberry Pi GPIO connector to the Cobbler.