CAVEDU Education
Published © GPL3+

App Inventor + IoT: Wi-Fi RGB LED control with LinkIt 7697

This tutorial will show you how to control LinkIt 7697 with App Inventor to control a RGB LEDwith four different colors by buttons.

AdvancedFull instructions provided3 hours1,734
App Inventor + IoT: Wi-Fi RGB LED control with LinkIt 7697

Things used in this project

Hardware components

LinkIt 7697
LinkIt 7697
RGB LED (common cathode)


Read more




arduino sketch

  WiFi 7697 LED control
  If the IP address of your shield is yourAddress:
  http://yourAddress/R to light red
  http://yourAddress/G to light green
  http://yourAddress/B to light blue
  http://yourAddress/W to light white
  http://yourAddress/o to turn off LED

    LinkIt 7697 HDK
    RGB LED (common cathode) 
    R - LinkIt D11
    G - LinkIt D9
    B - LinkIt D7

  created 25 Nov 2012
  by Tom Igoe
  modified 3 Nov 2017
#include <LWiFi.h>

char ssid[] = "ssid";      //  your network SSID (name)
char pass[] = "pass";   // your network password
int keyIndex = 0;                 // your network key Index number (needed only for WEP)

int status = WL_IDLE_STATUS;
WiFiServer server(80);

void setup() {
  Serial.begin(9600);      // initialize serial communication
  pinMode(LED_BUILTIN, OUTPUT);      // set the LED pin mode
  pinMode(11, OUTPUT);  //R
  pinMode(9, OUTPUT);   //G
  pinMode(7, OUTPUT);   //B

  // attempt to connect to Wifi network:
  while (status != WL_CONNECTED) {
    Serial.print("Attempting to connect to Network named: ");
    Serial.println(ssid);                   // print the network name (SSID);

    // Connect to WPA/WPA2 network. Change this line if using open or WEP network:
    status = WiFi.begin(ssid, pass);
  server.begin();                           // start the web server on port 80
  printWifiStatus();                        // you're connected now, so print out the status

void loop() {
  WiFiClient client = server.available();   // listen for incoming clients

  if (client) {                             // if you get a client,
    Serial.println("new client");           // print a message out the serial port
    String currentLine = "";                // make a String to hold incoming data from the client
    while (client.connected()) {            // loop while the client's connected
      if (client.available()) {             // if there's bytes to read from the client,
        char c =;             // read a byte, then
        Serial.write(c);                    // print it out the serial monitor
        if (c == '\n') {                    // if the byte is a newline character

          // if the current line is blank, you got two newline characters in a row.
          // that's the end of the client HTTP request, so send a response:
          if (currentLine.length() == 0) {
            // HTTP headers always start with a response code (e.g. HTTP/1.1 200 OK)
            // and a content-type so the client knows what's coming, then a blank line:
            client.println("HTTP/1.1 200 OK");

            // the content of the HTTP response follows the header:
            client.print("Click <a href=\"/R\">here</a> to light red<br>");
            client.print("Click <a href=\"/G\">here</a> to light green<br>");
            client.print("Click <a href=\"/B\">here</a> to light blue<br>");
            client.print("Click <a href=\"/W\">here</a> to light white<br>");
            client.print("Click <a href=\"/o\">here</a> to light off<br>");

            // The HTTP response ends with another blank line:
            // break out of the while loop:
          } else {    // if you got a newline, then clear currentLine:
            currentLine = "";
        } else if (c != '\r') {  // if you got anything else but a carriage return character,
          currentLine += c;      // add it to the end of the currentLine

        // Check client request
        if (currentLine.startsWith("GET /R")) {  // GET /R to light red
        if (currentLine.startsWith("GET /G")) {  // GET /G to light green
        if (currentLine.startsWith("GET /B")) {  // GET /B to light blue
        if (currentLine.startsWith("GET /W")) {  // GET /W to light white
        if (currentLine.startsWith("GET /o")) {  // GET /o to light off
    // close the connection:
    Serial.println("client disonnected");

void printWifiStatus() {
  // print the SSID of the network you're attached to:
  Serial.print("SSID: ");

  // print your WiFi shield's IP address:
  IPAddress ip = WiFi.localIP();
  Serial.print("IP Address: ");

  // print the received signal strength:
  long rssi = WiFi.RSSI();
  Serial.print("signal strength (RSSI):");
  Serial.println(" dBm");
  // print where to go in a browser:
  Serial.print("To see this page in action, open a browser to http://");

void led(int R, int G, int B) {
  digitalWrite(11, R);
  digitalWrite(9, G);
  digitalWrite(7, B);

App Inventor aia

No preview (download only).


CAVEDU Education

CAVEDU Education

11 projects • 28 followers
We provide tutorials of robotics, Arduino, Raspberry Pi and IoT topics.