Arduino Proto Shield Rev3 (assembled)
The Prototyping Shield makes it easy for you to design custom circuits. You can solder parts to the prototyping area to create your project, or use it with a small solderless breadboard (not included) to quickly test circuit ideas without having to solder. It's got extra connections for all of the Arduino I/O pins, and it's got space to mount through-hole and surface mount integrated circuits. It's a convenient way to make your custom circuit and Arduino into a single module.
The wide prototyping area has some extra features:
1.0 Arduino Pinout
1 ICSP Connector foortprint
14 pin SMD footprint (50 mils pitch)
20 pin Through Hole footprint (100 mils pitch)
For more information about the SPI communication see the SPI library.
The maximum length and width of the Proto Shield PCB are 2.7 and 2.1 inches respectively. Three screw holes allow the shield to be attached to a surface or case. Note that the distance between digital pins 7 and 8 is 160 mil (0.16"), not an even multiple of the 100 mil spacing of the other pins.