DFRobot 4 Channel Relay Shield for Arduino This arduino relay shield acts like a switch. It is commonly used to control anything over 5V such as lamps, water pumps and garage doors. This relay shield is an ideal solution for home automation and robotics applications Compatible with Arduino UNO Rev3 Each Relay has its own test button to test the connection Standard DFRobot 3 Pin out; XBee I/O direct control