1-channel 5 V relay module

A switch controlled by the ESP32: when the relay is activated, the coil pulls the contact and COM moves from NC to NO (you can hear the click; here, with Sound on). Most modules are active-low: rele.value(0) turns it on and rele.value(1) turns it off. Mains loads only with the teacher present.

Pinout

Pin	Connect to	Note
IN	GPIO (e.g. 26)	control
VCC	VIN (5 V)
GND	GND
COM	common of the load	middle terminal
NO	load that turns on when activated	normally open
NC	load that turns on when released	normally closed

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MicroPython example

from machine import Pin
import time

rele = Pin(26, Pin.OUT, value=1)  # active-low: 1 = off

while True:
    rele.value(0)  # on: COM moves to NO (click!)
    time.sleep(2)
    rele.value(1)  # off: COM goes back to NC
    time.sleep(2)

Specifications

Item	Value	Source
Power supply	5 V (VIN)	Typical datasheet values
Control	most are active-low (choose it in the part’s property)	Typical datasheet values
Contacts	COM, NO (normally open), NC (normally closed)	Typical datasheet values
IN input	read with the ESP32 thresholds; floating IN = off	Simulator model — Under review: real input threshold of the module with VCC at 5 V and IN at 3.3 V
Pin header order	IN, VCC, GND	Typical datasheet values — Under review: check on the lab module

Values marked "Under review" will still be checked against the parts in the lab.