A great introduction to starting out with Radio Frequency (RF) Networking. Use your computer to control a remote application or have the application control the computer. This bundle + guide will get you up and running with RF networking in a practical way.
This breadboard-compatible module is an alternative to bulky power switches. It uses a small integrated slide switch to control a high-side power MOSFET that can deliver continuous currents up to around 16 A at 4.5V to 40V.