Documentation

Overview

This 4-Channel Programmable Relay Module is a complete standalone delay/timer/sequencing controller built around an on-board microcontroller, a 4-digit 7-segment display, four optoisolated trigger inputs, and four 10A relays. Each channel can be programmed for delay-on, delay-off, pulse, or motor-reversing modes — all through the on-board SET/UP/DOWN/OK buttons. No microcontroller required for basic use.

Typical applications include garage door automation, water pump cycling, lighting sequences, motor reversal control (forward / pause / reverse), and any project where you need accurate sub-second to multi-hour timed switching of mains-voltage loads. The module supports two power inputs: a 6.5-25V terminal block (for vehicle / industrial applications) and a 5V DC barrel jack (for desktop power supplies).

For projects that need a microcontroller in the loop, each of the 4 trigger inputs is optoisolated and accepts a 5V or 3.3V signal — wire them to GPIO pins on an Arduino, ESP32, Raspberry Pi, or Pico to fire any pre-programmed timing sequence on demand.

At a Glance

Specifications

Pinout Diagram

Wiring Guide

Code Examples

Arduino - Trigger All 4 Channels in Sequence

// 4-Channel programmable relay - fire each input in sequence
// Wire IN1-IN4 to D2-D5, share GND with the module

const int triggers[4] = {2, 3, 4, 5};

void setup() {
  for (int i = 0; i < 4; i++) {
    pinMode(triggers[i], OUTPUT);
    digitalWrite(triggers[i], LOW);
  }
}

void pulseTrigger(int pin) {
  digitalWrite(pin, HIGH);
  delay(100);                  // 100 ms pulse fires the channel
  digitalWrite(pin, LOW);
}

void loop() {
  for (int i = 0; i < 4; i++) {
    pulseTrigger(triggers[i]);
    delay(2000);               // wait between channels
  }
}

Raspberry Pi (Python)

#!/usr/bin/env python3
# 4-channel programmable relay - sequence trigger from Pi GPIO

import RPi.GPIO as GPIO
import time

TRIGGERS = [17, 27, 22, 23]   # GPIO 17, 27, 22, 23
GPIO.setmode(GPIO.BCM)
for p in TRIGGERS:
    GPIO.setup(p, GPIO.OUT, initial=GPIO.LOW)

try:
    while True:
        for p in TRIGGERS:
            GPIO.output(p, GPIO.HIGH)
            time.sleep(0.1)
            GPIO.output(p, GPIO.LOW)
            time.sleep(2)
except KeyboardInterrupt:
    GPIO.cleanup()

Frequently Asked Questions