How to read data into App Inventor from Wifi module

[Ade Tuck]

Hi,

I have a HP-SR04 distance sensor connected to an ArdaFruit Huzzah ESP8266 Wi-Fi board.

I have the WiFi board reading the distance sensor data ok and displaying it on the screen,

I would like to squirt those distance numbers into App Inventor

Here is my Arduino code, i am just a beginner so its the last line that (I think) that sends the data out.

Can someone create or explain what App inventor blocks i need to use to read this distance data on my phone please ?

Ignore the LED stuff, its just old code and i was worried i might break something if i delete it... NooB here :)

Thanks 

Adrian 

#include <ESP8266WiFi.h>

#include <WiFiClient.h>

#include <ESP8266WebServer.h>

#include <ESP8266mDNS.h>

const char* ssid = "***";

const char* password = "**"

ESP8266WebServer server(80);

const int led = 0;

const int led2 = 2;

const int trigPin = 12;

const int echoPin = 15 ;

long duration;

int distance;

void handleRoot() {

  digitalWrite(led, 1);

  server.send(200, "text/bold", "HELLO!");

  digitalWrite(led, 0);

}

void handleNotFound(){

  digitalWrite(led, 1);

  String message = "File Not Found\n\n";

  message += "URI: ";

  message += server.uri();

  message += "\nMethod: ";

  message += (server.method() == HTTP_GET)?"GET":"POST";

  message += "\nArguments: ";

  message += server.args();

  message += "\n";

  for (uint8_t i=0; i<server.args(); i++){

    message += " " + server.argName(i) + ": " + server.arg(i) + "\n";

  }

  server.send(404, "text/plain", message);

  digitalWrite(led, 0);

}

void setup(void){

  Serial.begin(115200);

  WiFi.begin(ssid, password);

  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output

  pinMode(echoPin, INPUT); // Sets the echoPin as an Input

  Serial.println("");

  // Wait for connection

  while (WiFi.status() != WL_CONNECTED) {

    delay(500);

    Serial.print(".");

  }

  Serial.println("");

  Serial.print("Connected to ");

  Serial.println(ssid);

  Serial.print("IP address: ");

  Serial.println(WiFi.localIP());

  if (MDNS.begin("esp8266")) {

    Serial.println("MDNS responder started");

  }

  server.on("/", handleRoot);

  server.on("/RON", [](){

   digitalWrite(led, 1);

   server.send(200, "text/plain", "Red LED On");    

  });

  server.on("/ROFF", [](){

   digitalWrite(led, 0);

   server.send(200, "text/plain", "Red LED Off");   

  });

  server.on("/BON", [](){

   digitalWrite(led2, 1);

   server.send(200, "text/plain", "Blue LED On");    

  });

  server.on("/BOFF", [](){

   digitalWrite(led2, 0);

   server.send(200, "text/plain", "Blue LED Off");   

  });

  

  server.onNotFound(handleNotFound);

  server.begin();

  Serial.println("HTTP server started");

}

void loop(void){

  server.handleClient();

// Clears the trigPin

digitalWrite(trigPin, LOW);

delayMicroseconds(2);

// Sets the trigPin on HIGH state for 10 micro seconds

digitalWrite(trigPin, HIGH);

delayMicroseconds(10);

digitalWrite(trigPin, LOW);

// Reads the echoPin, returns the sound wave travel time in microseconds

duration = pulseIn(echoPin, HIGH);

// Calculating the distance

distance= duration*0.034/2;

// Prints the distance on the Serial Monitor

Serial.print("Distance: ");

Serial.println(distance); 

server.send(distance);

}  

[Abraham Getzler]

https://groups.google.com/forum/#!searchin/mitappinventortest/ESP8266

Try the second link, from Robert Holt, for short code.

ABG

[Ade Tuck]

Thanks for the link Abraham,

So is my above Arduino code ok ? 

Will it keep sending out distance data from the last line of code ?

Or do i need to put it in a loop ?  

I made a text box, in the App Inventor, and used the lower block of code from the link you sent me:

But when i try running the App inventor on my phone its not showing any distance data from the Huzzah board.

Any ideas ?

Don't forget I am super new at this so i might be missing some basic info.

Thanks 

[Abraham Getzler]

Easiest way to test a system is one part at a time.

Can you query the ESP device from a web browser?

Does the returned Web output look reasonable?

ABG