4 Channel Relay Shield for Arduino UNO

The 4 Channel Relay Shield for Arduino UNO is an optocoupler-isolated expansion board designed to switch high-power AC and DC appliances directly from an Arduino UNO Rev3. It is ideal for students, makers, and educators retrofitting home automation systems, IoT setups, and multi-device control projects.

Shield format for clean integration

The board stacks straight onto an Arduino UNO Rev3, eliminating messy breadboard wiring and loose jumper leads. It provides up to four independently controlled channels to operate devices such as lighting, pumps, fans, and garage doors.

XBee socket and sensor pinout

An on-board XBee interface allows direct integration of wireless modules like Bluetooth, WiFi, or Zigbee for IoT and smart home networking. The shield also brings out 14 digital three-pin ports and 6 analog three-pin ports for connecting extra sensors and components.

Optocoupler isolation and safety design

Each channel includes optocoupler isolation and independent power routing to completely separate high-voltage AC/DC loads from the micro-controller logic. This stops electromagnetic interference and protects the Arduino board from high-voltage spikes.

Onboard manual test buttons and LEDs

Each relay features its own dedicated manual test button and an LED status indicator to quickly verify switching operations during setup. Relay control lines can also be assigned across selectable digital IO pins, with default mapping to pins 2, 7, 8, and 10.

Electrical ratings and durability

The relays deliver a maximum switching current of 5A with a maximum switching voltage of AC 240V or DC 60V (under 38V recommended). They are rated for a minimum electrical life of 100,000 operations and 10,000,000 mechanical cycles across an operating temperature range of -30°C to +85°C.

Supplied hardware

The package includes one Relay Shield for Arduino along with two nylon stand-offs and screws for secure mechanical mounting.

Downloads & documentation

• Product wiki (DFRobot)