The DFRobot Relay Module is a standard relay used with a controller board to interface external electrical circuits or modules. Some of the most common applications with Arduino are: Home lighting, electrical appliances of high power and other equipments. The modular design makes it easy to integrate with a controller board. The Relay integrates a status LED, in order to acknoledge visually it's status ON or OFF. It can be controlled through the digital IO port, with a simple HIGH or LOW on Arduino compatible boards. Other boards will work requiring same voltage level. Other usages include control of solenoid valves, lamps, motors and other high current or high voltage devices.