ENS160 + AHT21 Sensor for Arduino

Interface an ESP 8266 WeMos module with an ENS160+AHT21 CARBON Dioxide CO2 eCO2 TVOC Air Quality And Temperature And Humidity Sensor.

I never found much information about this cheap module from AliExpress.

https://www.aliexpress.us/w/wholesale-ens160%2Baht21.html?spm=a2g0o.detail.search.0

This module combines two sensors on one module making it very easy to connect to. I used the I2C to interface with a ESP8266 WeMos module. I think you can use any microcontroller that has a I2C interface. I only use these cheap sensors to see if things change over time. They are not accurate enough for exact numbers.

VIN is 5 volts..my unit had 2 voltage regulators on it for the sensors. 65K5=1.8V and a 662K 3.3V; both have max input of 6 volts. The 3.3V pin is a low current output from the 66K5 regulator-don't use.

These are the libraries I used.

Adafruit AHTX0

ENS160 - Adafruit Fork

Below is the sketch I used for basic testing.

========================================================

/*

Tim TEST ENS160+AHT21

a 20231201 start testing.

*/

/***************************************************************************

ENS160 - Digital Air Quality Sensor

This is an example for ENS160 basic reading in standard mode

Updated by Sciosense / 25-Nov-2021

***************************************************************************/

#include <Wire.h>

int ArduinoLED = 2;

///// AHT20 start

#include <Adafruit_AHTX0.h>

Adafruit_AHTX0 aht;

//Variables Tim, reused same names so I did not have to change much.

int tempC; //To store the temperature in C

int tempF; //temp in F

int humidity; //To store the humidity

///// AHT20 end

#include "ScioSense_ENS160.h" // ENS160 library

//ScioSense_ENS160 ens160(ENS160_I2CADDR_0); //0x52

ScioSense_ENS160 ens160(ENS160_I2CADDR_1); //0x53..ENS160+AHT21

/*--------------------------------------------------------------------------

SETUP function

initiate sensor

--------------------------------------------------------------------------*/

void setup() {

Serial.begin(9600);

while (!Serial) {}

//Switch on LED for init

pinMode(ArduinoLED, OUTPUT);

digitalWrite(ArduinoLED, LOW);

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

Serial.println("ENS160 - Digital air quality sensor");

Serial.println();

Serial.println("Sensor readout in standard mode");

Serial.println();

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

delay(1000);

Serial.print("ENS160...");

ens160.begin();

Serial.println(ens160.available() ? "done." : "failed!");

if (ens160.available()) {

// Print ENS160 versions

Serial.print("\tRev: "); Serial.print(ens160.getMajorRev());

Serial.print("."); Serial.print(ens160.getMinorRev());

Serial.print("."); Serial.println(ens160.getBuild());

Serial.print("\tStandard mode ");

Serial.println(ens160.setMode(ENS160_OPMODE_STD) ? "done." : "failed!");

}

// AHT20 start

Serial.println("Adafruit AHT10/AHT20 demo!");

if (! aht.begin()) {

Serial.println("Could not find AHT? Check wiring");

while (1) delay(10);

}

Serial.println("AHT10 or AHT20 found");

//AHT20 end

} //end void setup

/*--------------------------------------------------------------------------

MAIN LOOP FUNCTION

Cylce every 1000ms and perform measurement

--------------------------------------------------------------------------*/

void loop() {

///// AHT20 start

sensors_event_t humidity1, temp; //Tim had to change to humidity1

aht.getEvent(&humidity1, &temp);// populate temp and humidity objects with fresh data

tempC = (temp.temperature);

tempF = (temp.temperature)*1.8+32;

humidity = (humidity1.relative_humidity);

Serial.print("Temperature: ");

Serial.print(tempC);

Serial.println(" degrees C");

Serial.print("Temperature: ");

Serial.print(tempF);

Serial.println(" degrees F");

Serial.print("Humidity: ");

Serial.print(humidity);

Serial.println("% rH");

delay(1000);

///// AHT20 end

if (ens160.available()) {

// Give values to Air Quality Sensor.

ens160.set_envdata(tempC, humidity);

ens160.measure(true);

ens160.measureRaw(true);

Serial.print("AQI: ");Serial.print(ens160.getAQI());Serial.print("\t");

Serial.print("TVOC: ");Serial.print(ens160.getTVOC());Serial.print("ppb\t");

Serial.print("eCO2: ");Serial.print(ens160.geteCO2());Serial.println("ppm\t");

//Serial.print("R HP0: ");Serial.print(ens160.getHP0());Serial.print("Ohm\t");

//Serial.print("R HP1: ");Serial.print(ens160.getHP1());Serial.print("Ohm\t");

//Serial.print("R HP2: ");Serial.print(ens160.getHP2());Serial.print("Ohm\t");

//Serial.print("R HP3: ");Serial.print(ens160.getHP3());Serial.println("Ohm");

}

delay(1000);

} //end void loop

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