ESP32 MiCS-4514 Dual Gas Sensor

Code Examples

Below you can find code examples of MiCS-4514 Dual Gas Sensor with ESP32 in several frameworks:

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

ESP32 MiCS-4514 Arduino IDE Code Example

Example in Arduino IDE

Fill in your main Arduino IDE sketch file with the following code to use the MiCS-4514 Dual Gas Sensor:

#include <Wire.h>

const int reducingGasPin = 19; // Analog input for reducing gas
const int oxidizingGasPin = 18; // Analog input for oxidizing gas
const int heaterPin = 5; // Digital output for heater control

void setup() {
    Serial.begin(9600);

    // Configure heater pin
    pinMode(heaterPin, OUTPUT);
    digitalWrite(heaterPin, HIGH); // Turn on the heater
}

void loop() {
    int reducingGasValue = analogRead(reducingGasPin);
    int oxidizingGasValue = analogRead(oxidizingGasPin);

    // Convert analog values to voltage
    float reducingGasVoltage = reducingGasValue * (5.0 / 1023.0);
    float oxidizingGasVoltage = oxidizingGasValue * (5.0 / 1023.0);

    Serial.print("Reducing Gas Voltage: ");
    Serial.print(reducingGasVoltage);
    Serial.println(" V");

    Serial.print("Oxidizing Gas Voltage: ");
    Serial.print(oxidizingGasVoltage);
    Serial.println(" V");

    delay(1000);
}

This Arduino sketch interfaces with the MiCS-4514 sensor using GPIO19 and GPIO18 for reducing and oxidizing gas outputs. GPIO5 controls the heater, which is turned on during setup. The analog readings are converted to voltage and printed to the Serial Monitor every second.

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 MiCS-4514 ESP-IDF Code Example

Example in Espressif IoT Framework (ESP-IDF)

If you're using ESP-IDF to work with the MiCS-4514 Dual Gas Sensor, 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 "driver/adc.h"
#include "esp_adc_cal.h"
#include "driver/gpio.h"

#define REDUCING_GAS_CHANNEL ADC1_CHANNEL_7 // GPIO19
#define OXIDIZING_GAS_CHANNEL ADC1_CHANNEL_6 // GPIO18
#define HEATER_PIN GPIO_NUM_5
#define DEFAULT_VREF 1100

void app_main(void) {
    // Configure heater pin
    gpio_pad_select_gpio(HEATER_PIN);
    gpio_set_direction(HEATER_PIN, GPIO_MODE_OUTPUT);
    gpio_set_level(HEATER_PIN, 1); // Turn on the heater

    // Configure ADC
    adc1_config_width(ADC_WIDTH_BIT_12);
    adc1_config_channel_atten(REDUCING_GAS_CHANNEL, ADC_ATTEN_DB_11);
    adc1_config_channel_atten(OXIDIZING_GAS_CHANNEL, ADC_ATTEN_DB_11);

    esp_adc_cal_characteristics_t *adc_chars = calloc(1, sizeof(esp_adc_cal_characteristics_t));
    esp_adc_cal_characterize(ADC_UNIT_1, ADC_ATTEN_DB_11, ADC_WIDTH_BIT_12, DEFAULT_VREF, adc_chars);

    while (1) {
        uint32_t reducing_raw = adc1_get_raw(REDUCING_GAS_CHANNEL);
        uint32_t oxidizing_raw = adc1_get_raw(OXIDIZING_GAS_CHANNEL);

        uint32_t reducing_voltage = esp_adc_cal_raw_to_voltage(reducing_raw, adc_chars);
        uint32_t oxidizing_voltage = esp_adc_cal_raw_to_voltage(oxidizing_raw, adc_chars);

        printf("Reducing Gas Voltage: %d mV\n", reducing_voltage);
        printf("Oxidizing Gas Voltage: %d mV\n", oxidizing_voltage);

        vTaskDelay(pdMS_TO_TICKS(1000));
    }
}

This ESP-IDF example reads analog voltages from the MiCS-4514 sensor using GPIO19 and GPIO18 for reducing and oxidizing gases. GPIO5 is used to control the heater. The ADC values are converted to millivolts and printed to the console every second.

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 MiCS-4514 ESPHome Code Example

Example in ESPHome (Home Assistant)

Fill in this configuration in your ESPHome YAML configuration file (example.yml) to integrate the MiCS-4514 Dual Gas Sensor

sensor:
  - platform: adc
    pin: GPIO19
    name: "Reducing Gas Voltage"
    update_interval: 1s
  - platform: adc
    pin: GPIO18
    name: "Oxidizing Gas Voltage"
    update_interval: 1s

gpio:
  - platform: output
    pin: GPIO5
    id: heater_control

interval:
  - interval: 1s
    then:
      - output.turn_on: heater_control

This ESPHome configuration uses GPIO19 and GPIO18 for the reducing and oxidizing gas outputs of the MiCS-4514 sensor, and GPIO5 to control the heater. The analog values are updated every second and displayed as sensors.

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

ESP32 MiCS-4514 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:esp32dev]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200

ESP32 MiCS-4514 PlatformIO Example Code

Write this code in your PlatformIO project under the src/main.cpp file to use the MiCS-4514 Dual Gas Sensor:

#include <Arduino.h>

const int reducingGasPin = 19; // Analog input for reducing gas
const int oxidizingGasPin = 18; // Analog input for oxidizing gas
const int heaterPin = 5; // Digital output for heater control

void setup() {
    Serial.begin(115200);

    // Configure heater pin
    pinMode(heaterPin, OUTPUT);
    digitalWrite(heaterPin, HIGH); // Turn on the heater
}

void loop() {
    int reducingGasValue = analogRead(reducingGasPin);
    int oxidizingGasValue = analogRead(oxidizingGasPin);

    float reducingGasVoltage = reducingGasValue * (3.3 / 4095.0);
    float oxidizingGasVoltage = oxidizingGasValue * (3.3 / 4095.0);

    Serial.print("Reducing Gas Voltage: ");
    Serial.print(reducingGasVoltage);
    Serial.println(" V");

    Serial.print("Oxidizing Gas Voltage: ");
    Serial.print(oxidizingGasVoltage);
    Serial.println(" V");

    delay(1000);
}

This PlatformIO example reads analog voltages from GPIO19 and GPIO18 for the reducing and oxidizing gas outputs of the MiCS-4514 sensor. GPIO5 is used to control the heater. The values are converted to voltage and printed to the Serial Monitor every second.

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

ESP32 MiCS-4514 MicroPython Code Example

Example in Micro Python Framework

Fill in this script in your MicroPython main.py file (main.py) to integrate the MiCS-4514 Dual Gas Sensor with your ESP32.

from machine import ADC, Pin
import time

# Pin definitions
reducing_adc = ADC(Pin(19))  # Analog input for reducing gas
oxidizing_adc = ADC(Pin(18))  # Analog input for oxidizing gas
heater_pin = Pin(5, Pin.OUT) # Digital output for heater control

# Configure ADC
reducing_adc.atten(ADC.ATTN_11DB)
oxidizing_adc.atten(ADC.ATTN_11DB)

# Turn on the heater
heater_pin.on()

while True:
    reducing_voltage = reducing_adc.read() * (3.3 / 4095)
    oxidizing_voltage = oxidizing_adc.read() * (3.3 / 4095)

    print(f"Reducing Gas Voltage: {reducing_voltage:.2f} V")
    print(f"Oxidizing Gas Voltage: {oxidizing_voltage:.2f} V")
    time.sleep(1)

This MicroPython script uses GPIO19 and GPIO18 for reading reducing and oxidizing gas voltages from the MiCS-4514 sensor. GPIO5 controls the heater. The ADC values are scaled to voltage and printed every second.

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