The boards in this guide are all self-contained. You can use them without adding any additional switches, sensors, lights, or buzzers. 

But it's also simple to add more components -- without soldering or breadboards! Large holes around the edges of the CPX and Gemma let you work with the boards in multiple ways:

• You can attach alligator clip wires to the holes.
• You can attach conductive foil or fabric tape.
• You can sew through the holes with conductive thread.
• You can attach component wires with small screws.

And because the boards are small and light, you can wear them using stick-on pin backs or hang them from lanyards. You can also connect them to their battery cases or to your project with common craft materials, such as glue dots or peel-and-stick Velcro tabs. This makes them easy to re-use when the project is done.