ESP32 Sharp GP2Y1010AU0F Optical Dust Sensor

#include <stdio.h>
#include <stdlib.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/adc.h"
#include "esp_adc_cal.h"
#include "driver/gpio.h"
#include "esp_system.h"
#include "esp_log.h"
#include "rom/ets_sys.h"  // For microsecond delays

#define LED_PIN 2              // Change to the GPIO pin connected to the LED
#define ADC_CHANNEL ADC1_CHANNEL_6 // GPIO34 (ADC1_CH6)
#define DEFAULT_VREF 1100       // Default ADC reference voltage in mV
#define NO_OF_SAMPLES 64        // Number of ADC samples for averaging

static esp_adc_cal_characteristics_t adc_chars = NULL;
static const char TAG = "ESP32_ADC_Task";

// Function to initialize ADC
void init_adc() {
    ESP_ERROR_CHECK(adc1_config_width(ADC_WIDTH_BIT_12));
    ESP_ERROR_CHECK(adc1_config_channel_atten(ADC_CHANNEL, ADC_ATTEN_DB_0));

    adc_chars = calloc(1, sizeof(esp_adc_cal_characteristics_t));
    if (adc_chars == NULL) {
        ESP_LOGE(TAG, "Failed to allocate memory for ADC characteristics");
        return;
    }

    // Check and calibrate ADC using eFuse Vref
    if (esp_adc_cal_check_efuse(ESP_ADC_CAL_VAL_EFUSE_VREF) == ESP_OK) {
        esp_adc_cal_characterize(ADC_UNIT_1, ADC_ATTEN_DB_0, ADC_WIDTH_BIT_12, DEFAULT_VREF, adc_chars);
    } else {
        ESP_LOGW(TAG, "eFuse Vref not available, using default Vref");
        esp_adc_cal_characterize(ADC_UNIT_1, ADC_ATTEN_DB_0, ADC_WIDTH_BIT_12, DEFAULT_VREF, adc_chars);
    }
}

// Function to read ADC value
uint32_t read_adc_value() {
    uint32_t adc_reading = 0;
    for (int i = 0; i < NO_OF_SAMPLES; i++) {
        adc_reading += adc1_get_raw(ADC_CHANNEL);
    }
    adc_reading /= NO_OF_SAMPLES; // Average

    // Convert raw ADC value to voltage (mV)
    uint32_t voltage = esp_adc_cal_raw_to_voltage(adc_reading, adc_chars);
    ESP_LOGI(TAG, "Raw ADC: %lu, Voltage: %lu mV", (unsigned long)adc_reading, (unsigned long)voltage);
    return voltage;
}

// Function to initialize LED
void init_led() {
    gpio_reset_pin(LED_PIN);
    gpio_set_direction(LED_PIN, GPIO_MODE_OUTPUT);
}

// Task to blink LED with precise timing
void led_task(void pvParameters) {
    while (1) {
        gpio_set_level(LED_PIN, 1);
        ets_delay_us(280);  // 280µs delay (sub-millisecond precision)
        gpio_set_level(LED_PIN, 0);
        vTaskDelay(pdMS_TO_TICKS(1000));  // Delay for 1 second
    }
}

// Task to read ADC values
void adc_task(void pvParameters) {
    while (1) {
        read_adc_value();
        vTaskDelay(pdMS_TO_TICKS(2000));  // Read ADC every 2 seconds
    }
}

// Main function
void app_main() {
    init_led();
    init_adc();

    xTaskCreate(led_task, "LED Task", 2048, NULL, 2, NULL);
    xTaskCreate(adc_task, "ADC Task", 2048, NULL, 2, NULL);
}