====== lamaPLC: ENS160 + AHT21 Air Quality Sensor - CO, ECO, TVOC, Temp & Humidity Module ======

{{ :sensor:ens160_1.png?150|ENS160 + AHT21 Air Quality Sensor}}
The ENS160 + AHT21 Air Quality Module is a combined environmental sensor board that measures indoor air pollutants (VOCs, eCO<sub>2</sub>, AQI) and climate conditions (Temperature, Humidity). It is a popular upgrade for older sensors like the CCS811 due to its integrated sensor fusion and automatic calibration.

  * Detection of reducing (VOC) and oxidizing gases (such as NO<sub>2</sub>)
  * MOX supports up to 4 gas sensors
  * Integrated sensor measurement and heater drive control
  * Integrated pre-calibrated sensor fusion and automatic correction algorithm

**Key Capabilities**

  * **ENS160 (Air Quality):** Uses Metal-Oxide (MOX) technology to detect reducing and oxidizing gases.
    * **Outputs:** Total Volatile Organic Compounds (TVOC), equivalent CO<sub>2</sub> (eCO<sub>2</sub>) ), and Air Quality Index (AQI).
    * **Target Gases:** Ethanol, toluene, hydrogen, NO<sub>2</sub>, and ozone.
  * **AHT21 (Climate):** A high-precision digital temperature and humidity sensor.
    * **Temperature:** ±0.3 °C accuracy; range of -40 °C to +120 °C.
    * **Humidity:** ±2 % RH accuracy; range of 0 to 100 % RH. 

**Technical Specifications**
|< 100%>|
^Feature^Specification|
^Supply Voltage (VIN)|2.0V to 5.5V DC (Breakout boards often regulate to 3.3V)|
^Interface|[[com:basic_i2c|I²C]] (Standard) or [[com:basic_spi|SPI]] (ENS160 only)|
^I2C Addresses|ENS160: **0x53** (default) or **0x52**; AHT21: **0x38**|
^Warm-up Time| < 1 minute for immediate use; up to 1 An hour for full accuracy|
^Power Use|1.2 to 46 mW depending on operating mode|

==== Pinout ====
^Pin Name^Type^Description|
^VIN / VCC|Power|Power supply input. Usually supports 3.3V to 5V due to onboard regulators.|
^GND|Power|Ground connection.|
^SCL|I²C|Serial Clock line for both ENS160 and AHT21.|
^SDA|I²C|Serial Data line for both ENS160 and AHT21.|
^ADDR / ADO|Control|(Optional) I²C address selection for ENS160. Connect to GND for 0x52 or VCC for 0x53.|
^INT|Output|(Optional) Interrupt pin; can signal when new data is ready.|

==== Example Arduino code ====
To use the ENS160 + AHT21 module with Arduino, you'll typically need two libraries from the Arduino Library Manager: Adafruit ENS160 and Adafruit AHTX0. 

**Install Required Libraries**
 
Open the Arduino IDE and install the following: 

  * Adafruit ENS160 Library
  * Adafruit AHTX0 Library (works for both AHT20 and AHT21)
  * Adafruit Unified Sensor (dependency for many Adafruit libraries)

This code initializes both sensors via I²C and prints climate and air quality data to the Serial Monitor every two seconds.

<code c>
#include <Wire.h>
#include <Adafruit_ENS160.h>
#include <Adafruit_AHTX0.h>

Adafruit_ENS160 ens160;
Adafruit_AHTX0 aht;

void setup() {
  Serial.begin(115200);
  while (!Serial) delay(10); // Wait for Serial Monitor

  Serial.println("ENS160 + AHT21 Test");

  // Initialize AHT21 (Address 0x38)
  if (!aht.begin()) {
    Serial.println("Could not find AHT21 sensor!");
    while (1) delay(10);
  }
  Serial.println("AHT21 initialized.");

  // Initialize ENS160 (Address 0x53 or 0x52)
  // Most combo boards default to 0x53
  if (!ens160.begin(0x53)) {
    Serial.println("Could not find ENS160 sensor!");
    while (1) delay(10);
  }
  
  // Set operating mode: Standard (detecting)
  ens160.setMode(ENS160_OPMODE_STD);
  Serial.println("ENS160 initialized.");
}

void loop() {
  // 1. Read Climate Data from AHT21
  sensors_event_t humidity, temp;
  aht.getEvent(&humidity, &temp);

  // 2. Feed Temperature/Humidity to ENS160 for better accuracy
  ens160.setTempRH(temp.temperature, humidity.relative_humidity);

  // 3. Read Air Quality Data from ENS160
  if (ens160.available()) {
    Serial.print("Temp: "); Serial.print(temp.temperature); Serial.println(" C");
    Serial.print("Humidity: "); Serial.print(humidity.relative_humidity); Serial.println(" %");
    
    Serial.print("AQI: "); Serial.println(ens160.getAQI());
    Serial.print("TVOC: "); Serial.print(ens160.getTVOC()); Serial.println(" ppb");
    Serial.print("eCO2: "); Serial.print(ens160.getECO2()); Serial.println(" ppm");
    Serial.println("-----------------------");
  }

  delay(2000);
}
</code>

**Usage Tips**

  * Baud Rate: Set your Serial Monitor to 115200 to match the code above.
  * Warm-up: The ENS160 requires about 1 hour to achieve full accuracy, though it will start providing initial readings within 1 minute.
  * Address Conflict: If the ENS160 is not found, try changing //ens160.begin(0x53)// to //ens160.begin(0x52)//.
  * Library Alternatives: If the Adafruit library doesn't work for your specific breakout, the //DFRobot_ENS160// library is a highly compatible alternative.

===== I2C topics on lamaPLC =====
{{topic>i2c}}

{{tag>arduino ENS160 AHT21 Air_Quality sensor CO ECO TVOC module AQI}}

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