#Arduino relay how to
#Arduino relay code

Connections for the K2, K3 and K4 are the same.

Relay 1 (K1): Connect one end of the load to the COM and the other end to the NO.

When you will use the relays in NO (Normally Open) connection and you set the corresponding IN pin to LOW, then the power will flow from the COM connector and out of the normally open connector powering your device.

We will use the normally open connection.

When we will trigger the relay module then it will open the circuit, so the connection is lost. It always remains in contact with COM, even when relay module is not powered.

NC (Normally closed): its behavior is opposite to the normally open connection.

Thus the circuit will initially be in open state until we trigger the state. But when we will activate the relay module, then it will get connected to the COM and will supply power to the load, which will power up the light. In normally open connection, there will be no contact between COM and NO, since it is normally open.

NO (Normally open): This act like a switch.

COM (Common connection): The COM is the center terminal of the relay and it is used in both (Normally open and normally closed) connections.

you may also like to read Xbee interfacing with arduinoīefore getting into the output connections of the relay, we have to understand the NO, COM and NC connections.

You can also power the 4 relay module using the external power by giving voltage from 5 to 24V DC.

Logic VCC: This will be connected to the 5v pin of the Arduino o power the 4 relay module.

Input4 (IN 4): This will be connected to the digital pin on your Arduino, or leave it unconnected if you do not want to use this channel.

Input3 (IN 3): This will be connected to the digital pin on your Arduino, or leave it unconnected if you do not want to use this channel.

Input2 (IN 2): This will be connected to the digital pin on your Arduino, or leave it unconnected if you do not want to use this channel.

Input 1 (IN 1): This will be connected to digital pin on your Arduino, or leave it unconnected if

Logic GND: This will be connected to GND on your Arduino.

#Arduino relay how to

I recommend you to learn how to use digital output of arduino microcontroller.

Relay Module Pinout Input Connections of relay module

Once you will understand this then you can use all other types. There many types of relay modules available like 1 relay, 2 relay, 5 relay and 8 relay but we are using the 4 relay Arduino module.

#Arduino relay code

Code of relay module interfacing with microcontroller Relay Module.

Video lecture on Arduino with relay module.