Tuesday, October 20, 2020
Home Arduino Strarter Kit KY-019 | ARDUINO RELAY MODULE


Arduino can control a lot of devices only when they work with 5V. Most of the devices that we have might not work with just 5V. Some Need Higher voltages just like your home appliances. A typical house bulb works with 220V/110V depending on where you leave. Horns in Car Uses 12V to operate. To make an Arduino operate this kind of device we need the KY-019 Realy Module. It is also useful to operate devices that use higher currents.

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  • 5V – 12 V TTL control signal
  • Maximum AC and voltage: 10A 250VAC
  • Maximum DC and voltage: 10A 30VDC
  • The control signal DC or AC, 220V AC load can be controlled
  • There is a normally open and one normally closed contact
  • To make the coil of relay energized you just need to have an input of 1 in the
    signal pin.

How does the KY-019 work :

This magnetic field helps in joining two open contacts on the secondary side and completing the circuit, generating the flow of current. Depending on the type of relay, a relay can operate voltages from 30V to 10000 V.
It can be used to work on both AC and DC voltages,

KY-019 Pin Configuration :

KY-019 Relay Module

There is 6 Pin in a relay module.

  • Normally Open
  • Normally Closed
  • Common
  • Vcc
  • GND
  • Signal

Normally closed is used when to pass current until the signal line is activated. Normally open is used when to pass current until the signal line is deactivated. The common terminal is shared between the two contacts. We can use either the Normally closed or Normally Open terminals or both at the same time.

 Arduino Wiring :

Firstly connect KY-019 Module GND to Arduino GND.

Then Connect KY-019 Module Vcc+ to Arduino +5V.

Lastly, Connect KY-019 Module Signal to Arduino PIN 8.

 Arduino Code :

int RelayPIN = 8; // define the relay signal pin
void setup ()
  pinMode (RelayPIN, OUTPUT); // set the pin to output
void loop ()
  // activate the relay
  // normally closed pin stops sending current
  // normally open pin starts sending current
  digitalWrite (GPRelayPIN, HIGH);
  delay (2000); // pause for 2 seconds
  // deactivate the relay
  // normally open pin stops sending current
  // normally closed pin starts sending current
  digitalWrite (GPRelayPIN, LOW); 
  delay (2000); // pause for 2 seconds


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