Microbit and AHT20 temperature and humidity sensor Arduino example

In this article we look at another temperature and humidity sensors – this time its the AHT20 and we will connect it to our Microbit and see what it can do

First lets take a look at the sensor in question, this is from the datasheet

Parts Required

Once again for ease of use I connect an expansion board to the microbit, I feel this makes it easier to connect to a sensor like the one pictured above using connecting wire

Schematic/Connection

The layout below shows a Microbit, I used a Microbit v1

If you have an ESP32 board with a STEMMA QT cables, you can use these:

Black for GND
Red for V+
Blue for SDA
Yellow for SCL

microbit and aht20 layout

Code Example

This example uses a couple of libraries, both of which can be installed using the library manager. if you search for the AHT20 one first and you are using a newer version of the Arduino IDE it will install the other one as well – which makes things a bit easier.

You need the Adafruit library for the AHT20 from https://github.com/adafruit/Adafruit_AHTX0

You also need an I2C support library from the same folks for the library above to work and that is available from – https://github.com/adafruit/Adafruit_BusIO

This is the simple test example that comes with the library

[codesyntax lang=”cpp”]

#include <Adafruit_AHTX0.h>

Adafruit_AHTX0 aht;

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

void loop() 
{
  sensors_event_t humidity, temp;
  aht.getEvent(&humidity, &temp);
  // populate temp and humidity objects with fresh data
  Serial.print("Temperature: "); 
  Serial.print(temp.temperature); 
  Serial.println(" degrees C");
  Serial.print("Humidity: "); 
  Serial.print(humidity.relative_humidity); 
  Serial.println("% rH");

  delay(500);
}

[/codesyntax]

Output

Open the serial monitor and you should see something like this

Temperature: 20.99 degrees C
Humidity: 43.30% rH
Temperature: 20.99 degrees C
Humidity: 43.32% rH
Temperature: 21.01 degrees C
Humidity: 43.27% rH
Temperature: 20.99 degrees C
Humidity: 43.32% rH
Temperature: 21.74 degrees C
Humidity: 42.96% rH

Links

Product download pdf