HOW to Use Relay with ESP32

Overview

In our daily life, we usually use communication to drive electrical equipments, and sometimes we use switches to control electrical equipments. If the switch is connected directly to the ac circuit, leakage occurs and people are in danger. Therefore, from the perspective of safety, we specially designed this relay module with NO(normally open) end and NC(normally closed) end.

Working Principle

Relay is compatible with a variety of micro-controller control board, such as Arduino series micro-controller, which is a small current to control the operation of large current “automatic switch”.

Input Voltage：3.3V-5V

It can let the MCU control board drive 3A load, such as an LED lamp belt, a DC motor, a micro water pump and a solenoid valve plugable interface design, which is easy to use.

Components Required

Connection Diagram

Test Code

from machine import Pin
import time

# create relay from Pin 15, Set Pin 15 to output 
relay = Pin(15, Pin.OUT)
 
# The relay is opened, COM and NO are connected on the relay, and COM and NC are disconnected.
def relay_on():
    relay(1)
 
# The relay is closed, the COM and NO on the relay are disconnected, and the COM and NC are connected.
def relay_off():
    relay(0)
 
# Loop, the relay is on for one second and off for one second
while True:
    relay_on()
    time.sleep(1)
    relay_off()
    time.sleep(1)

Test Result

Connect the wires according to the experimental wiring diagram and power on. Click “Run current script”, the code starts executing. The relay will cycle on and off, on for 1 second, off for 1 second. At the same time, you can hear the sound of the relay on and off as well as see the change of the indicator light on the relay.

Press“Ctrl+C”or click“Stop/Restart backend”to exit the program.