ESP32 KY-019 5V Relay Module

🛠️ KY-019 5V Relay Module Troubleshooting

This guide outlines a systematic approach to troubleshoot and resolve common problems with the . Start by confirming that the hardware connections are correct, as wiring mistakes are the most frequent cause of issues. If you are sure the connections are correct, follow the below steps to debug common issues.

❌ Relay Not Activating

⚠️ Unstable Relay Operation

💻 Code Examples

Below you can find code examples of KY-019 5V Relay Module with ESP32 in several frameworks:

• Arduino IDE
• ESP-IDF
• ESPHome
• PlatformIO
• MicroPython

If you encounter issues while using the KY-019 5V Relay Module, check the Common Issues Troubleshooting Guide.

ESP32 KY-019 Arduino IDE Code Example

Example in Arduino IDE

Fill in your main Arduino IDE sketch file with the following code to use the KY-019 5V Relay Module:

int relayPin = 10; // Relay connected to digital pin 10

void setup() {
    pinMode(relayPin, OUTPUT);
    Serial.begin(9600);
    Serial.println("KY-019 Relay Module Test");
}

void loop() {
    digitalWrite(relayPin, HIGH); // Turn relay on
    Serial.println("Relay is ON");
    delay(1000); // Wait for a second
    digitalWrite(relayPin, LOW); // Turn relay off
    Serial.println("Relay is OFF");
    delay(1000); // Wait for a second
}

This Arduino code sets up the KY-019 relay module on digital pin 10. It alternates the relay state every second, turning it on and off, while printing the status to the serial monitor.

Connect your ESP32 to your computer via a USB cable, Ensure the correct Board and Port are selected under Tools, Click the "Upload" button in the Arduino IDE to compile and upload the code to your ESP32.

ESP32 KY-019 ESP-IDF Code Example

Example in Espressif IoT Framework (ESP-IDF)

If you're using ESP-IDF to work with the KY-019 5V Relay Module, here's how you can set it up and read data from the sensor. Fill in this code in the main ESP-IDF file:

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"

#define RELAY_PIN GPIO_NUM_5

void app_main(void) {
    gpio_config_t io_conf = {
        .pin_bit_mask = (1ULL << RELAY_PIN),
        .mode = GPIO_MODE_OUTPUT,
        .pull_up_en = GPIO_PULLUP_DISABLE,
        .pull_down_en = GPIO_PULLDOWN_DISABLE,
        .intr_type = GPIO_INTR_DISABLE
    };
    gpio_config(&io_conf);

    printf("KY-019 Relay Module Test\n");

    while (1) {
        gpio_set_level(RELAY_PIN, 1); // Turn relay on
        printf("Relay is ON\n");
        vTaskDelay(pdMS_TO_TICKS(1000)); // Wait for a second
        gpio_set_level(RELAY_PIN, 0); // Turn relay off
        printf("Relay is OFF\n");
        vTaskDelay(pdMS_TO_TICKS(1000)); // Wait for a second
    }
}

This ESP-IDF code configures GPIO5 as an output to control the KY-019 relay module. It toggles the relay state every second, turning it on and off, while printing the status to the console.

Update the I2C pins (I2C_MASTER_SDA_IO and I2C_MASTER_SCL_IO) to match your ESP32 hardware setup, Use idf.py build to compile the project, Use idf.py flash to upload the code to your ESP32.

ESP32 KY-019 ESPHome Code Example

Example in ESPHome (Home Assistant)

Fill in this configuration in your ESPHome YAML configuration file (example.yml) to integrate the KY-019 5V Relay Module

switch:
  - platform: gpio
    pin: GPIO5
    name: "KY-019 Relay"
    icon: "mdi:relay"
    restore_mode: ALWAYS_OFF

This ESPHome configuration sets up the KY-019 relay module on GPIO5 as a switch. The relay can be controlled from Home Assistant and will always start in the OFF state when powered up.

Upload this code to your ESP32 using the ESPHome dashboard or the esphome run command.

ESP32 KY-019 PlatformIO Code Example

Example in PlatformIO Framework

For PlatformIO, make sure to configure the platformio.ini file with the appropriate environment and libraries, and then proceed with the code.

Configure platformio.ini

First, your platformio.ini should look like below. You might need to include some libraries as shown. Make sure to change the board to your ESP32:

[env:esp32]
platform = espressif32
board = esp32dev
framework = arduino

ESP32 KY-019 PlatformIO Example Code

Write this code in your PlatformIO project under the src/main.cpp file to use the KY-019 5V Relay Module:

#include <Arduino.h>

#define RELAY_PIN 5

void setup() {
    pinMode(RELAY_PIN, OUTPUT);
    Serial.begin(115200);
    Serial.println("KY-019 Relay Module Test");
}

void loop() {
    digitalWrite(RELAY_PIN, HIGH);
    Serial.println("Relay is ON");
    delay(1000);
    digitalWrite(RELAY_PIN, LOW);
    Serial.println("Relay is OFF");
    delay(1000);
}

This PlatformIO code configures GPIO5 as an output for the KY-019 relay module. The relay toggles ON and OFF every second, with the status printed to the serial monitor.

Upload the code to your ESP32 using the PlatformIO "Upload" button in your IDE or the pio run --target upload command.

ESP32 KY-019 MicroPython Code Example

Example in Micro Python Framework

Fill in this script in your MicroPython main.py file (main.py) to integrate the KY-019 5V Relay Module with your ESP32.

import machine
import time

RELAY_PIN = machine.Pin(5, machine.Pin.OUT)

while True:
    RELAY_PIN.value(1)
    print("Relay is ON")
    time.sleep(1)
    RELAY_PIN.value(0)
    print("Relay is OFF")
    time.sleep(1)

This MicroPython script configures GPIO5 as an output to control the KY-019 relay module. The relay turns ON and OFF every second, with messages printed to the console.

Upload this code to your ESP32 using a MicroPython-compatible IDE, such as Thonny, uPyCraft, or tools like ampy.