# Air quality sensor module, VOC, MICS-4514, 5V

> Air quality sensor module with MICS-4514 sensor, 5 V DC supply, Arduino compatible. Detects reducing gases (CO, NH3, ethanol, H2, methane/propane/isobutane) on the RO output and oxidizing gases (NO2) on the OX output, providing two separate analog outputs. Includes an En pin for heater activation. Current draw ~25-35mA, operating temperature -20~50°C, dimensions 17x14 mm.

- Page: https://sigmanortec.ro/en/air-quality-sensor-module-voc-mics-4514-5v
- Price: 199.17 RON
- Availability: Out of stock
- Reference: 88153 · EAN: 5945255201725
- Category: Mechatronics and IoT > Sensors and Modules > Gas and Air Quality Sensors
- Specifications: Input Voltage: 5 V; Input Voltage Type: “DC” in Romanian can mean **“de ce”**, which translates to **“why”** in English.; Measured quantity: VOC; Sensor used: MICS-4514
- Updated: 2026-09-14
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-10-22 04:50 (Europe/Bucharest)

## Description

The air quality monitoring module detects reducing and oxidizing gases such as CO, NO2, NH3, ethanol, or H2, providing two separate analog outputs RO and OX for clear readings. Compatible with Arduino, operates at 5V, and includes an En pin for heater control and optimal power consumption. Compact size 17x14 mm, ideal for smart home projects and industrial applications.
The MiCS-4514 module is an air quality sensor compatible with Arduino and other development boards, designed to detect and measure concentrations of gases such as carbon monoxide (CO), nitrogen dioxide (NO2), ammonia (NH3), ethanol, hydrogen (H2), and methane, propane, or isobutane in various environments.
The sensor uses advanced MEMS technology and integrates two completely independent detection elements in a single compact 17 x 14 mm package, providing a versatile solution for air quality monitoring in residential and office spaces as well as industrial applications.
Unlike single-output sensors, the module generates two separate analog values: the RO pin for reducing gases (CO, NH3, ethanol, H2, methane, propane, isobutane) and the OX pin for oxidizing gases (NO2), allowing clear differentiation of the types of gases detected.
An important advantage is the enable pin (En) for the heater, which allows low power usage by activating the sensor heater only when necessary, by setting the En pin to HIGH.
The module operates at a 5 VDC power supply, with a current consumption of approximately 25-35 mA during heating, and supports operating temperatures between -20 and 50 degrees Celsius.
Specifications:
Power supply voltage: 5 VDC
Current consumption: ~25-35mA (for sensor heating)
Interface: Analog with two outputs for reading concentrations
Operating temperature: -20 ~ 50°C
Detected gases: CO, NO2, NH3, Ethanol, H2, CH4, C3H8, C4H10
Output pin 1 (RO): CO, NH3, Ethanol, H2, Methane/Propane/Isobutane (Reducing gases)
Output pin 2 (OX): NO2 (Oxidizing gas)
Dimensions: 17 x 14 mm
Detection range:
Carbon monoxide (CO): 1 ~ 1000 ppm
Nitrogen dioxide (NO2): 0.05 ~ 10 ppm
Ammonia (NH3): 1 ~ 500 ppm
Ethanol: 10 ~ 500 ppm
Hydrogen (H2): 1 ~ 1000 ppm
Methane/Propane/Isobutane: >1000 ppm
Pinout:
Pin
Example Arduino connection
Function
VCC
5V
Module power supply 5 VDC
GND
Ground
RO
A0
Analog output for reducing gases (CO, NH3, ethanol, H2, methane)
OX
A1
Analog output for oxidizing gases (NO2)
En
D7 (or connected to 5V)
Enable for sensor heater (HIGH to activate)
Usage:
Connect the module to the Arduino board according to the pinout above and ensure the power supply is stable at 5 VDC.
Set the En pin to HIGH to activate the sensor heater.
Let the sensor warm up for about 3 minutes in a clean air environment before starting readings.
Read the analog values from the RO pin (A0) for reducing gases and from the OX pin (A1) for oxidizing gases.
Monitor the variations of the read values over time to detect increases or decreases in gas concentration.
Set alarm thresholds in your code to signal potentially dangerous concentrations.
Use averages of multiple consecutive readings for more stable results and avoid strong air currents directly on the sensor.
If you need ppm estimates, perform calibration in the target environment and compare with reference values, as the response varies depending on gas, temperature, and humidity.
Test connections with Arduino:
Pin
Arduino Uno connection
Function
VCC
5V
Module power supply
GND
Ground
RO
A0
Analog output reducing gases (CO, NH3, ethanol, H2, methane)
OX
A1
Analog output oxidizing gases (NO2)
En
D7
Heater enable (HIGH to activate)