Scan Networks
This example scans for 802.11b/g networks with the Arduino WiFi Shield 101 or a MKR1000 board. Your Arduino Software (IDE) serial monitor will print out information about the board and the networks it can see. It will not connect to a network.
Hardware Required
- Arduino WiFi Shield 101
- Arduino or Genuino Zero board
or
- MKR1000
Circuit
Digital pin 7 is used as a handshake pin between the WiFi Shield 101 and the board, and should not be used.
Open your Arduino Software (IDE) serial monitor to view the networks the WiFi shield 101 can see. The shield may not see as many networks as your computer.
image developed using Fritzing. For more circuit examples, see the Fritzing project page
In the above image, the Arduino or Genuino Zero board would be stacked below the WiFi shield.
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 <WiFi101.h>
void setup() {
//Initialize serial and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port 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: ");
printMacAddress(mac);
}
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));
Serial.flush();
}
}
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;
}
}
void printMacAddress(byte mac[]) {
for (int i = 5; i >= 0; i--) {
if (mac[i] < 16) {
Serial.print("0");
}
Serial.print(mac[i], HEX);
if (i > 0) {
Serial.print(":");
}
}
Serial.println();
}
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 <WiFi101.h>
void setup() {
//Initialize serial and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port 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: ");
printMacAddress(mac);
}
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));
Serial.flush();
}
}
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;
}
}
void printMacAddress(byte mac[]) {
for (int i = 5; i >= 0; i--) {
if (mac[i] < 16) {
Serial.print("0");
}
Serial.print(mac[i], HEX);
if (i > 0) {
Serial.print(":");
}
}
Serial.println();
}
See Also:
- WiFi library – Your reference for the WiFi101 Library.
- WiFi Shield – Product details for the WiFi 101 Shield.
- MKR1000 – Product details for the MKR1000 board.
- Connect No Encryption - Demonstrates how to connect to an open network.
- Connect With WEP - Demonstrates how to connect to a network that is encrypted with WEP.
- Connect With WPA - Demonstrates how to connect to a network that is encrypted with WPA2 Personal.
- Simple Web Server WiFi – Turn on and off an LED accessing this simple Web Server.
- UDP NTP Client - Query a Network Time Protocol (NTP) server using UDP.
- WiFi Chat Server - Set up a simple chat server.
- WiFi Web Client - Connect to a remote webserver.
- WiFi Web Client Repeating - Repeatedly make HTTP calls to a server.
- WiFi Web Server - Serve a webpage from the WiFi shield with Analog Input values.
- WiFi Send Receive UDP String - Send and receive a UDP string.
Last revision 2016/04/16 by SM
