Sharp GP2Y1010AU0F Optical Dust Sensor

// The GP2Y1010AU0F requires sampling its analog output DURING the 320 us LED
// pulse (sample ~280 us after switching the LED on) - the timing is what makes
// the reading meaningful.
#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_rom_sys.h"

#define LED_PIN     GPIO_NUM_25     // LED drive pin (GPIO25, matches the wiring above)
#define ADC_CHANNEL ADC1_CHANNEL_6  // Vo on GPIO34 (ADC1_CH6)
#define DEFAULT_VREF 1100

static esp_adc_cal_characteristics_t adc_chars;

void app_main(void) {
    gpio_reset_pin(LED_PIN);
    gpio_set_direction(LED_PIN, GPIO_MODE_OUTPUT);
    gpio_set_level(LED_PIN, 1); // LED off (active low through the drive circuit)

    ESP_ERROR_CHECK(adc1_config_width(ADC_WIDTH_BIT_12));
    ESP_ERROR_CHECK(adc1_config_channel_atten(ADC_CHANNEL, ADC_ATTEN_DB_11)); // Vo can reach ~3 V
    esp_adc_cal_characterize(ADC_UNIT_1, ADC_ATTEN_DB_11, ADC_WIDTH_BIT_12, DEFAULT_VREF, &adc_chars);

    while (1) {
        // Sharp's datasheet timing: LED on, sample at 280 us, LED off at 320 us
        gpio_set_level(LED_PIN, 0);         // LED on
        esp_rom_delay_us(280);
        int raw = adc1_get_raw(ADC_CHANNEL); // Sample while the LED is on
        esp_rom_delay_us(40);
        gpio_set_level(LED_PIN, 1);         // LED off

        uint32_t voltage_mv = esp_adc_cal_raw_to_voltage(raw, &adc_chars);
        // Approximate dust density per the datasheet curve: ~0.5 V per 0.1 mg/m3,
        // with a no-dust offset around 0.6 V (calibrate for your own sensor)
        float dust_ugm3 = (voltage_mv / 1000.0 - 0.6) / 0.5 * 100.0;
        if (dust_ugm3 < 0) dust_ugm3 = 0;

        printf("Vo: %lu mV, Dust density: %.0f ug/m3\n", (unsigned long)voltage_mv, dust_ugm3);
        vTaskDelay(pdMS_TO_TICKS(1000)); // The 10 ms pulse cycle is only needed for continuous operation
    }
}

[env:esp32dev]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
lib_deps =
    luciansabo/Sharp GP2Y Dust Sensor @ ^1.1.0

#include <Arduino.h>
#include <GP2YDustSensor.h>

const uint8_t SHARP_LED_PIN = 25; // LED drive pin (GPIO25, matches the wiring above)
const uint8_t SHARP_VO_PIN = 34;  // Analog output Vo (GPIO34 / ADC1_CH6)

GP2YDustSensor dustSensor(GP2YDustSensorType::GP2Y1010AU0F, SHARP_LED_PIN, SHARP_VO_PIN);

void setup() {
  Serial.begin(115200);
  //dustSensor.setBaseline(0.4); // set no-dust voltage according to your own experiments
  //dustSensor.setCalibrationFactor(1.1); // calibrate against a precision instrument
  dustSensor.begin();
}

void loop() {
  Serial.print("Dust density: ");
  Serial.print(dustSensor.getDustDensity());
  Serial.print(" ug/m3; Running average: ");
  Serial.print(dustSensor.getRunningAverage());
  Serial.println(" ug/m3");
  delay(1000);
}

from machine import Pin, ADC
import time

# Pins per the wiring above: LED drive on GPIO25, Vo on GPIO34 (ADC1)
led_pin = Pin(25, Pin.OUT)
adc = ADC(Pin(34))
adc.width(ADC.WIDTH_12BIT)
adc.atten(ADC.ATTN_11DB)  # Vo can reach ~3V

led_pin.value(1)  # LED off (active low through the recommended drive circuit)

def read_dust_density():
    # Sharp datasheet timing: LED on, sample at 280 us, LED off
    led_pin.value(0)
    time.sleep_us(280)
    raw_value = adc.read()
    led_pin.value(1)

    voltage = raw_value * (3.3 / 4095.0)
    # Datasheet curve: ~0.5 V per 0.1 mg/m3 above a ~0.6 V no-dust offset
    dust_ugm3 = (voltage - 0.6) / 0.5 * 100.0
    return max(dust_ugm3, 0)

while True:
    print("Dust Density: {:.0f} ug/m3".format(read_dust_density()))
    time.sleep(1)