Electronic – arduino – WiFi shield not present error

arduinoarduino-shieldwifi

I just bought the Arduino Wifi Shield. I've followed the setup instructions and uploaded their code but I get the error: "WiFi shield not present". No LEDS are ON on the Shield . I use the Arduino Uno 2009. Not the newest R3 version, so I did the connection for the 3.3V. Why the code is not working?

The Code

/*

 This example  prints the Wifi shield's MAC address, and
 scans for available Wifi networks using the Wifi shield.
 Every ten seconds, it scans again. It doesn't actually 
 connect to any network, so no encryption scheme is specified.

 Circuit:
 * WiFi shield attached

 created 13 July 2010
 by dlf (Metodo2 srl)
 modified 21 Junn 2012
 by Tom Igoe and Jaymes Dec
 */


#include <SPI.h>
#include <WiFi.h>

void setup() {
  //Initialize serial and wait for port to open:
  Serial.begin(9600); 
  while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }

  // check for the presence of the shield:
  if (WiFi.status() == WL_NO_SHIELD) {
    Serial.println("WiFi shield not present"); 
    // don't continue:
    while(true);
  } 

  // Print WiFi MAC address:
  printMacAddress();

  // scan for existing networks:
  Serial.println("Scanning available networks...");
  listNetworks();
}

void loop() {
  delay(10000);
  // scan for existing networks:
  Serial.println("Scanning available networks...");
  listNetworks();
}

void printMacAddress() {
  // the MAC address of your Wifi shield
  byte mac[6];                     

  // print your MAC address:
  WiFi.macAddress(mac);
  Serial.print("MAC: ");
  Serial.print(mac[5],HEX);
  Serial.print(":");
  Serial.print(mac[4],HEX);
  Serial.print(":");
  Serial.print(mac[3],HEX);
  Serial.print(":");
  Serial.print(mac[2],HEX);
  Serial.print(":");
  Serial.print(mac[1],HEX);
  Serial.print(":");
  Serial.println(mac[0],HEX);
}

void listNetworks() {
  // scan for nearby networks:
  Serial.println("** Scan Networks **");
  int numSsid = WiFi.scanNetworks();
  if (numSsid == -1)
  { 
    Serial.println("Couldn't get a wifi connection");
    while(true);
  } 

  // print the list of networks seen:
  Serial.print("number of available networks:");
  Serial.println(numSsid);

  // print the network number and name for each network found:
  for (int thisNet = 0; thisNet<numSsid; thisNet++) {
    Serial.print(thisNet);
    Serial.print(") ");
    Serial.print(WiFi.SSID(thisNet));
    Serial.print("\tSignal: ");
    Serial.print(WiFi.RSSI(thisNet));
    Serial.print(" dBm");
    Serial.print("\tEncryption: ");
    printEncryptionType(WiFi.encryptionType(thisNet));
  }
}

void printEncryptionType(int thisType) {
  // read the encryption type and print out the name:
  switch (thisType) {
  case ENC_TYPE_WEP:
    Serial.println("WEP");
    break;
  case ENC_TYPE_TKIP:
    Serial.println("WPA");
    break;
  case ENC_TYPE_CCMP:
    Serial.println("WPA2");
    break;
  case ENC_TYPE_NONE:
    Serial.println("None");
    break;
  case ENC_TYPE_AUTO:
    Serial.println("Auto");
    break;
  } 
}

Best Answer

The problem was that the Arduino need to be connected to a power source + the USB cable. The USB cable on its own did not provide enought voltage for the shield to be detected. I plugged the 9V source to the USB and the shield works perfectly now!

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