Environmental sensor module, ENS160+AHT21, temperature, humidity, VOC, 5V

The ENS160 + AHT21 module is a compact solution for complete indoor air monitoring, combining temperature and humidity measurement with gas and volatile organic compound detection.

Integrating the two sensors into a single board gives you stable data for smart home and HVAC automation, and I2C or SPI communication makes connecting to Arduino and other platforms simple.

It has a low consumption of approximately 10mA, 5V power supply, small dimensions and a weight of only 3g, making it easy to mount even in narrow housings.

The module includes voltage regulators on the board, so powering via VIN at 5V is appropriate, and the 3V3 pin is a low current output from the regulator and is not recommended to be used to power other consumers.

Specifications:

Supply voltage: 5V

Consumption: approximately 10mA

Communication interface: I2C, SPI

Gas and VOC detection: ozone, formaldehyde, ammonia, ethanol and other volatile organic compounds

VOC measurement range: 0-65535 ppb

ENS160 humidity range: 5-95% RH

ENS160 temperature range: -40-85C

ENS160 start time: under 60 minutes

AHT21 temperature range: -40-120C

AHT21 humidity range: 0-100% RH

AHT21 temperature accuracy: ±0.3C

AHT21 humidity accuracy: ±2% RH

AHT21 temperature resolution: 0.01C

AHT21 humidity resolution: 0.025% RH

Dimensions: 24 x 20mm

Pinout:

Use:

Power the module with 5V on VIN and connect common GND to the development board.

For I2C connect SDA and SCL to the dedicated pins of the board, for SPI use the specific pins and configure the library accordingly.

After powering up, let the ENS160 sensor stabilize, for relevant readings it is recommended to wait the 30 minute start-up period.

Mount the module in an area with representative airflow, away from condensation, water droplets, and direct heat from sources such as radiators or power boards.

For ventilation projects, use the VOC value as an indicator for increasing flow, and temperature and humidity for comfort control.

Avoid powering other consumers from the 3.3V. For safety, it is preferable to leave it unused.

Test Code:

/*

Test ENS160 + AHT21 module on Arduino using I2C

Displays: temperature, humidity and VOC in Serial Monitor

Typical I2C connections:

- Arduino UNO/Nano: SDA = A4, SCL = A5

- Arduino Mega: SDA = 20, SCL = 21

- 3.3V boards (ESP32, RP2040 etc): uses the board-specific I2C pins

Power supply: 3.3V recommended

*/

#include

#include "AHT21.h"

#include "ENS160.h"

// Sensor objects

AHT21 aht21;

ENS160 ens160;

// Display time

unsigned long lastPrint = 0;

const unsigned long intervalMs = 2000;

void setup()

{

Wire.begin();

Serial.begin(9600);

while (!Serial)

{

delay(10);

}

Serial.println("Starting ENS160 + AHT21 test...");

// Initialize AHT21

if (!aht21.begin())

{

Serial.println("AHT21 initialization error!");

while (1)

{

delay(100);

}

}

Serial.println("AHT21 OK");

// Initialize ENS160

if (!ens160.begin())

{

Serial.println("ENS160 initialization error!");

while (1)

{

delay(100);

}

}

Serial.println("ENS160 OK");

// Optional: set ENS160 operating mode

// If the library allows:

// ens160.setOperatingMode (ENS160_OPMODE_STANDARD);

Serial.println("Waiting for the ENS160 sensor to stabilize, the first values may vary.");

}

void loop()

{

// Reading AHT21

float temp = aht21.readTemperature ();

float rh = aht21.readHumidity ();

// Optional: T/RH compensation for ENS160

// ens160.setTempHumidity (temp, rh);

// Read VOC

uint16_t voc = ens160.readVOC();

// Display at fixed interval

if (millis() - lastPrint >= intervalMs)

{

lastPrint = millis();

Serial.print("Temperature: ");

if (isnan(temp))

Serial.print("N/A");

else

Serial.print(temp, 2);

Serial.println("C");

Serial.print("Humidity: ");

if (isnan(rh))

Serial.print("N/A");

else

Serial.print(rh, 2);

Serial.println(" %");

Serial.print("VOC: ");

Serial.print(voice);

Serial.println("ppb");

Serial.println("---------------------------");

}

}