Connecting Raspberry Pi Pico W to Wi-Fi with MicroPython

The Raspberry Pi Pico W features a built-in Wi-Fi module, allowing it to connect to the internet with ease.

By connecting to the internet, you can send messages to cloud services like AWS IoT Core, store historical data, and build advanced IoT systems.

MicroPython Code

No special setup is required to connect to Wi-Fi. You simply need to execute the connection code within your MicroPython program. It is that straightforward.

Let's take a look at the MicroPython code.

Simply replace the SSID and PASSWORD in this code, and execute it to connect to your Wi-Fi.

import time

import network  # type: ignore

time.sleep(10)

# Wi-Fi
SSID = "<Your SSID>"
PASSWORD = "<Your Password>"


def connect_wifi(ssid: str, password: str) -> network.WLAN:
    try:
        wlan = network.WLAN(network.STA_IF)
        wlan.active(True)
        wlan.connect(ssid, password)

        # Wait for connection
        max_wait = 10
        while max_wait > 0:
            if wlan.status() < 0 or wlan.status() >= 2:
                break
            max_wait -= 1
            print("Waiting for connection...")
            time.sleep(1)

        # Check connection status
        if wlan.status() != 3:
            raise RuntimeError(f"Network connection failed: {wlan.status()}")
        else:
            print("Connected")
            status = wlan.ifconfig()
            print("IP address:", status[0])
        return wlan
    except Exception as e:
        print(f"Failed to connect to Wi-Fi: {e}")
        raise e


if __name__ == "__main__":
    connect_wifi(SSID, PASSWORD)

Since this is simple code, I will explain only the wlan.status() part. wlan.status() returns the following values. The status is normal only when it returns 3; all other values indicate idle, connecting, or error states.

Value	Constant	Description
0	STAT_IDLE	Idle (connection not attempted)
1	STAT_CONNECTING	Connecting
2	STAT_WRONG_PASSWORD	Incorrect password
3	STAT_GOT_IP	Connection successful, IP address obtained
-1	STAT_NO_AP_FOUND	Specified AP not found
-2	STAT_CONNECT_FAIL	Failed to connect for other reasons

Wi-Fi Connection Persists After the Program Ends

I noticed after running it that the Wi-Fi connection is maintained even after the MicroPython program has finished execution.

Therefore, if you want to install any modules using the mip command (the MicroPython version of pip), you can follow this process: run the program above -> interrupt it with Ctrl-C -> execute mip.install().

Caution Regarding Storing Wi-Fi Passwords in Plain Text

In the code above, the Wi-Fi password is saved in plain text.

If you are placing the device in a location accessible to the general public, such as outdoors, you need to be mindful of security risks.

As far as I have researched, it is difficult to encrypt and use passwords on the Pico W alone, and it seems necessary to add external modules.

The following two measures are effective:

• Isolate the Wi-Fi network: Configure the Wi-Fi network that the Pico W connects to so that it cannot connect to other devices, allowing only the connection between Pico W ↔ Wi-Fi AP (Access Point) ↔ Internet.
• Connect to another terminal via Bluetooth instead of Wi-Fi to send data.

Summary

Because the Raspberry Pi Pico W has a built-in Wi-Fi module, it can easily connect to the internet, making it extremely useful as a device for IoT systems.

It is an amazing era where you can buy such a device for under 2,000 yen.

Since it is easy to create systems linked with the cloud, please give it a try.