Relay for Arduino to 220V

Introduction to relay 220V for Arduino

A relay is a relatively simple electromechanical device. Its operation consists of a coil that is energised (in this case to 5v) when this coil is driven generates a magnetic field that moves a metal inside and it opens or closes a circuit, i.e., as if it were an electric switch.

Relay Arduino
Relay Arduino

Principle of operation

As he has been said the relay is a mechanical system that frees two circuits. The relay works of two ways different, well normally closed or normally open:

  • Normally closed (NC): the circuit is always closed until the relay will be excited. I.e. If we connect a light bulb will remain off until we have a high signal from Arduino. (the opposite of logic, high signal off signal under power).
  • Normally open (NO): the circuit is open until we give a high signal, the circuit works the same as the sign of our Arduino.

Usually the relays have one or more connections of each type, according to for what you may need to use.


Characteristics of the sensor relay for Arduino

Work voltage5V DC
Dimensions2.0 cm x 2.0 cm x 0.3 cm
Voltage maximum230V
Maximum intensity10A

Connection of the relay for Arduino

The relay for Arduino prototyping design

Activated with a touch sensor, click here to find out more.

Relay Arduino prototyping
Relay Arduino prototyping

Wiring diagram of relay with an Arduino

Relay diagram
Relay diagram

In the schema has been added the part of connection to 220V, this tutorial is not among the basic have the danger of working with this tension. For this design will use an electric male, one of the wires connect it directly to the light bulb and the other to common relay, NC output connects to the bulb (can connect in officer and not vice versa). By safety recommend not have the Arduino connected to a PC and feed it with a feeder of mobile and whenever is did a change is disconnect from the network for work without tension. We insist that there is some danger in this circuit.

connection of the relay to 220v
connection of the relay to 220v

Programming of the relay

Explanation prior

This circuit will use a LED in parallel with the relay to check it and the capacitive sensor will light it or turning (as we have NO or NC connected)


pinLED int = 13;
int pinTouch = 8;

void setup() {}
 pinMode (pinLED, OUTPUT);
 pinMode (pinTouch, INPUT);

void loop() {}
 digitalWrite (pinLED, digitalRead (pinTouch));

Once programmed we will see how it changes the LED

Video of operation

Buy relays 220v for Arduino

In this link you will see a selection of several relays that you can buy at Amazon.

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