# How to connect to a WiFi network using an Arduino

> Learn how to connect an Arduino to a WiFi network using the WiFiNINA library, calling WiFi.begin() until it reports WL_CONNECTED and printing the device IP.

Author: [Flavio Copes](https://flaviocopes.com/about/) | Published: 2021-01-14 | Topics: [Arduino](https://flaviocopes.com/tags/electronics/) | Canonical: https://flaviocopes.com/arduino-connect-wifi/

Electronic devices you build with Arduino start to become very cool when you connect them to the network.

Let's see how to connect an Arduino to a WiFi network.

The Arduino must have WiFi connectivity, for example the [Arduino MKR WiFi 1010](https://flaviocopes.com/arduino-board-mkr-wifi-1010/), which is the one I use, or the [Arduino Uno WiFi Rev2](https://flaviocopes.com/arduino-board-uno-wifi-rev-2/) and others.

We're going to use the library [**WiFiNINA**](https://www.arduino.cc/en/Reference/WiFiNINA). This library is super handy and lets us connect to a WiFi network, but also create a WiFi network if we want.

Start your Arduino sketch using:

```cpp
#include <SPI.h>
#include <WiFiNINA.h>
```

> The [SPI library](https://www.arduino.cc/en/reference/SPI) is used by the WiFiNINA library, so load it as well. SPI stands for _Serial Peripheral Interface_

The `WiFiNINA` library gives us access, among other things, to the `WiFi` object that we're going to use.

Now let's work on the body of the `setup()` function, the only Arduino core function we're going to implement (we'll leave `loop()` empty).

```cpp
void setup() {

}
```

First, we're going to define 2 strings to hold the network name, the SSID, and the network password.

I use [Arduino Create](https://flaviocopes.com/arduino-create/), so I just use constants that I'll fill separately in the `Secret` tab:

```cpp
char ssid[] = SECRET_SSID;
char pass[] = SECRET_PASS;
```

Next we're going to initialize the Serial interface to communicate information from the Arduino back to Arduino Create:

```cpp
Serial.begin(9600);
```

And we wait until it's ready using

```cpp
while (!Serial);
```

Next we put WiFi.begin() inside a loop that checks if its return value is `WL_CONNECTED`, and keeps retrying every 2 seconds until it is:

```cpp
int status = WL_IDLE_STATUS;
while (status != WL_CONNECTED) {
  Serial.print("Connecting to ");
  Serial.println(ssid);
  status = WiFi.begin(ssid, pass);
  delay(2000);
}
```

We first initialize it to `WL_IDLE_STATUS`, another constant of WiFiNINA, but we could also initialize it to an empty string.

Once we end this loop we are connected and we can call the `WiFi.localIP()` method to get the device IP address and print it to the serial:

```cpp
Serial.print("IP address: ");
Serial.println(WiFi.localIP());
```

Here's the full program:

```cpp
#include <SPI.h>
#include <WiFiNINA.h>

void setup() {
  char ssid[] = SECRET_SSID;
  char pass[] = SECRET_PASS;

  Serial.begin(9600);
  while (!Serial);

  int status = WL_IDLE_STATUS;
  while (status != WL_CONNECTED) {
    Serial.print("Connecting to ");
    Serial.println(ssid);
    status = WiFi.begin(ssid, pass);
    delay(5000);
  }

  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
}

void loop() {

}
```

You have access to other information now, like the network SSID with `WiFi.SSID()` and the signal strength using `WiFi.RSSI()`:

```cpp
Serial.print("Signal strength in dBm: ");
Serial.print(WiFi.RSSI());
```

At this point you are connected and you can move on to other tasks.

Note: you might have a NINA firmware upgrade available. Add this check to your program:

```cpp
if (WiFi.firmwareVersion() < WIFI_FIRMWARE_LATEST_VERSION) {
  Serial.println("Firmware upgrade available");
}
```

to know if that's the case. If so, using the Arduino IDE (I can't see how to do this from Arduino Create) connect to the board then load the example sketch `File -> Examples -> WiFiNINA -> Tools -> FirmwareUpdater`

![Arduino IDE showing the FirmwareUpdater example sketch with ESP32BootROM.cpp tab open](https://flaviocopes.com/images/arduino-connect-wifi/Screen_Shot_2021-01-09_at_19.37.34.png)

Then open the `Tools -> WiFi101 / WiFiNINA Firmware Updater` menu:

![WiFi101/WiFiNINA Firmware Updater dialog with Arduino MKR WiFi 1010 selected and Update Firmware button](https://flaviocopes.com/images/arduino-connect-wifi/Screen_Shot_2021-01-09_at_19.35.15.png)

and press the `Update Firmware` button:

![Success dialog box with Arduino logo showing The firmware has been updated! message and OK button](https://flaviocopes.com/images/arduino-connect-wifi/Screen_Shot_2021-01-09_at_19.36.36.png)