RELAY SHEILD

The Relay Shield is designed as an Arduino compatible smart module with 4 mechanical relays. This is a simpler and easier way to control high voltage with maximum switching power of 35VDC 70W for each channel. This Relay Shield module is controlled directly by Arduino/Crowduino through digital IOs with an external 6.5 to 12V DC supply. The 4 onboard control keys used to control the high voltage without programming. It features four high-quality relays and provides NO/NC interfaces. And four dynamic LED indicators to show the on/off state of each relay. And the standardized shield form factor to provide a smooth connection to the Arduino/Seeeduino board or other Arduino compatible boards.

The Relays are basically electromagnetic switches in which the relay is energized by the control circuit. When a voltage and current are applied to the coil, the current and coil create a magnetic field. As a result, it attracts the COM terminal towards the NO terminal. When the applied voltage and current are removed from the control circuit,  the COM terminal returns to contact the NC terminal due to a mechanical force (usually a spring). The two “Control Circuit” terminals for each of four relays are controlled by only one Arduino Digital I/O pin. The Pins 4, 5, 6, and 7 control relays 4, 3, 2, and 1 respectively. These relay shields are used to control high voltage using low voltage, motor control, remote control, anti-hearing alarm, automatic temperature alarm, incubators, and so on.

Note: The pins on the Shield should not touch the USB connector of Arduino UNO when they are connected.

J1 Interface/Terminal Pin Description:

• COM1 (Common Pin): The relay pin is controlled from the digital pin.
• NC1 (Normally Closed): This terminal is connected to COM1 when the RELAY1 control pin (Digital 7 I/O pin) is set to low and disconnected when the RELAY1 control pin  set to high.
• NO1 (Normally Open): This terminal connected to COM1 when the RELAY1 control pin (Digital 7 I/O pin)set to high and disconnected when the RELAY1 control pin set to low.

Terminals J2-4 are similar to J1 except that they control RELAY2-RELAY4 respectively.