Wifi

Wifi connects a Juno program to a Wi-Fi network. Get the radio once at startup, call begin with the network's name and password, and wait until status reports that the connection is up.

Connecting to Wi-Fi

Get the board's radio once, at startup. ArduinoUno.getWifi() returns it on the boards with onboard Wi-Fi (UNO R4 WiFi, UNO WiFi Rev2 and UNO Q). The UNO R3 has no radio, so the compiler rejects ArduinoUno.getWifi() there; stack the retired Arduino WiFi Shield and take the same Wifi from new ArduinoWifiShield().getWifi() instead. A unit test passes mock(Wifi.class).

The credentials stay on the microSD card (see SD Card), so they are not written in the source. Wifi.begin starts the connection; poll Wifi.status() until it equals Wifi.STATUS_CONNECTED before using the network:

SdCard sd = new DataLoggerShield().getSdCard();
Wifi wifi = ArduinoUno.getWifi();

if (sd.begin()) {
    try (InputStream file = sd.open("application.properties")) {
        if (file != null) {
            Properties properties = new Properties();
            properties.load(file);
            wifi.begin(properties.getProperty("wifi.ssid"), properties.getProperty("wifi.password"));
        }
    } catch (IOException exception) {
        Serial.println("application.properties could not be read");
    }
}

A program that runs for a long time should also decide what to do after a disconnection, for example by calling Wifi.begin again before its next request.

Troubleshooting

• Wi-Fi never reaches STATUS_CONNECTED: check the network name and password, and the signal strength. A bounded retry loop keeps the failure visible.