ESP Rainmaker LED - C Programming Language

ESP Rainmaker is a platform from Espressif Systems that enables users to quickly develop and prototype IoT solutions. ESP Rainmaker provides an easy-to-use interface for configuring and managing Wi-Fi and cloud services on Espressif’s ESP32 and ESP8266 microcontrollers.

In this tutorial, we will learn how to control an LED connected to an ESP32 microcontroller using ESP Rainmaker and C Programming Language.

Hardware Requirements

• ESP32 development board
• LED
• Resistor
• Breadboard
• Jumper wires

Software Requirements

• ESP-IDF software development kit
• ESP Rainmaker agent
• C Programming Language

Wiring Diagram

Connect the LED to GPIO 2 of the ESP32 through a 330-ohm resistor.

Code Explanation

We will use the ESP-IDF software development kit to write C code for controlling the LED.

#include <stdio.h>
#include <freertos/FreeRTOS.h>
#include <freertos/task.h>
#include "esp_system.h"
#include "driver/gpio.h"
#include "esp_rmaker_core.h"
#include "esp_rmaker_device.h"
#include "esp_rmaker_light.h"

/* GPIO for the LED */
#define LED_GPIO 2

esp_rmaker_device_t *light_device;

/* Callback for updating the state of the LED */
esp_err_t led_write_cb(const char *dev_name, const char *prop_name, esp_rmaker_param_val_t val, void *priv_data)
{
    gpio_set_level(LED_GPIO, val.val.b);
    return ESP_OK;
}

/* Initialise the LED */
void led_init(void)
{
    /* Configure the GPIO for the LED */
    gpio_config_t io_conf;
    io_conf.intr_type = GPIO_INTR_DISABLE;
    io_conf.mode = GPIO_MODE_OUTPUT;
    io_conf.pin_bit_mask = (1 << LED_GPIO);
    io_conf.pull_down_en = 0;
    io_conf.pull_up_en = 0;
    gpio_config(&io_conf);

    /* Create a light device and add it to the ESP Rainmaker node */
    light_device = esp_rmaker_device_create("LED", "light", NULL);
    esp_rmaker_device_add_cb(light_device, led_write_cb, NULL);
    esp_rmaker_light_service_create_and_add_to_device(light_device, true, 100);
}

void app_main(void)
{
    /* Initialize the ESP Rainmaker agent */
    esp_rmaker_node_init();

    /* Initialise the LED */
    led_init();

    /* Start the ESP Rainmaker agent task */
    esp_rmaker_node_start();

    printf("ESP Rainmaker LED - C Programming Language\n");
}

First, we include the necessary header files. We then define the GPIO pin for the LED. We create a function led_write_cb that is called when the state of the LED changes. This function receives the new state as a Boolean value and updates the state of the LED using the GPIO library. We then create a function led_init to initialise the LED and add it as a light device to the ESP Rainmaker node.

In app_main, we initialise the ESP Rainmaker agent, initialise the LED and start the ESP Rainmaker agent task.

Build and Flash the Code

1. Install the ESP-IDF software development kit.
2. Download the ESP Rainmaker agent and extract the compressed file.
3. Navigate to the root directory of the extracted ESP Rainmaker agent and run the command make menuconfig.
4. Configure your Wi-Fi and ESP Rainmaker account settings.
5. Navigate to the directory rainmaker/examples/c/led and run the command make flash.

Control the LED

1. Open the ESP Rainmaker mobile app and connect to your device.
2. In the device settings, navigate to the “Light” tab and toggle the switch to turn the LED on or off.

Conclusion

In this tutorial, we learned how to use ESP Rainmaker and C Programming Language to control an LED connected to an ESP32 microcontroller. By leveraging the power of ESP Rainmaker, we were able to quickly set up a Wi-Fi and cloud-connected device without having to write extensive code.