Make an AQI device with Raspberry Pi Pico W and ENS160+AHT21 in 5 Steps

I received the ENS160+AHT21 sensor module yesterday. I can not wait for any more for the stuff. So, I build the AQI device right away.

I have to give credit to TimHanewich for his project on GitHub.

I changed it a little bit and recorded it below.

A data sampling and upload script, written in MicroPython, running on a Raspberry Pi Pico W.
An ENS160 Digital Metal Oxide Multi-Gas Sensor, is used for monitoring Carbon Dioxide (CO2), Total Volatile Organic Compounds (TOVC), and the Air Quality Index (AQI) of your home via the I2C protocol.
An AHT21 Integrated Temperature and Humidity Sensor is used to monitor the ambient temperature and humidity of your home via the I2C protocol.

Step 1

Get a USB cable with a Micro USB B port to connect Raspberry Pi Pico W to a PC (Windows).

Go to the MicroPython website to download the latest firmware for Pico W. The one I download is v1.23.0.

Hold the BOOTSEL button on Pico W, then connect to the PC.

After a few seconds, the PC will find a drive. Drag the uf2 file I downloaded above to it.

Step 2

Connect the two stuff. as below.

Step 3

Download the Thonny IDE and install it on the Windows. I downloaded v4.1.4.

Step 4

Prepare the code. The Code I updated can be downloaded here. src

Four files.

Edit settings.py to add the WiFI information and the post_url. You can change the sample_time to 300 for measuring every five minutes.

In the main.py, I changed line 27 to match the wiring above.

Step 5

Connect the Pico W with the PC.

Launch Thonny IDE. Click Run > Interpreter, and select MicroPyton (Raspberry Pi Pico). click OK.

Then, open the files one by one and save a copy to the device.

Select the main.py file. Then click the Green Play button.

I post the data to a php file to save it to the MySQL database.

The 4th item with high eco2 and tvoc, because I opened the bottle of Alcool isophopylique.

Here is what it looks like for the setup. I mounted them on a 2X4 block with screws. I can move it anywhere in the house. I can also use the battery to power it.

Option:

The database structure of database aqi_1

The setting of the URL in settings.py.

post_url:str = "https://gthree.win/tools/aqi-data.php"

The main part of aqi-data.php is as follows:

 
$data = json_decode(file_get_contents('php://input'));

$humidity = $data->{'humidity'};
$temperature = $data->{'temperature'};
$eco2 = $data->{'eco2'};
$aqi = $data->{'aqi'};
$tvoc = $data->{'tvoc'};
 
// Database connection 
$conn = new mysqli('localhost', 'username', 'password', 'aqi_1'); 
 
// Insert data Query 
$sql = "INSERT INTO env_status ( humidity, temperature, eco2, aqi, tvoc) 
VALUES ($humidity, $temperature, $eco2, $aqi, $tvoc)"; 
 
if ($conn->query($sql) === TRUE) { 
  echo "Insert your JSON record successfully"; 
}

Received the data and saved them to the database.