BMP180 Ajax refreshed webpage - Very Simple
Posted: Wed Dec 09, 2015 6:55 pmThis Sketch is a basic example of a page provided by the ESP with the data from a BMP180 attached to I2C.
This will provide Temperature, Pressure and Relative altitude (1 meter or 3 feet accuracy, pressure is relative to altitude).
The page is refreshed via AJAX request.....
This will provide Temperature, Pressure and Relative altitude (1 meter or 3 feet accuracy, pressure is relative to altitude).
The page is refreshed via AJAX request.....
Code: Select all
#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <Wire.h>
#include <SFE_BMP180.h>
SFE_BMP180 pressure;
double baseline; // baseline pressure
WiFiServer server(80);
WiFiClient client;
String HTTP_req;
void setup() {
Serial.begin(115200);
WiFi.begin("your-SSID", "your-WiFi-Password");
while (WiFi.status() != WL_CONNECTED)
{
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected");
// Start the server
server.begin();
Serial.println("Server started");
if (pressure.begin())
{
}
else
{
// Oops, something went wrong, this is usually a connection problem,
// see the comments at the top of this sketch for the proper connections.
Serial.println("BMP180 init fail (disconnected?)\n\n");
while(1); // Pause forever.
}
baseline = getPressure();
}
void loop() {
WiFiClient client = server.available();
if (client) {
boolean currentLineIsBlank = true;
while (client.connected()) {
if (client.available()) {
char c = client.read();
HTTP_req += c;
if (c == '\n' && currentLineIsBlank) {
client.println("HTTP/1.1 200 OK");
client.println("Content-Type: text/html");
client.println("Connection: keep-alive");
client.println();
if (HTTP_req.indexOf("ajax_switch") > -1) {
getTemperature(client);
} else {
client.println("<!DOCTYPE html>");
client.println("<html>");
client.println("<head>");
client.println("<title>ESP BMP180 web display</title>");
client.println("<script>");
client.println("function getTemperature() {");
client.println("nocache = \"&nocache=\"+ Math.random() * 1000000;");
client.println("var request = new XMLHttpRequest();");
client.println("request.onreadystatechange = function() {");
client.println("if (this.readyState == 4) {");
client.println("if (this.status == 200) {");
client.println("if (this.responseText != null) {");
client.println("document.getElementById(\"switch_txt\").innerHTML = this.responseText;");
client.println("}}}}");
client.println("request.open(\"GET\", \"ajax_switch\" + nocache, true);");
client.println("request.send(null);");
client.println("setTimeout('getTemperature()', 1000);");
client.println("}");
client.println("</script>");
client.println("</head>");
client.println("<body onload=\"getTemperature()\">");
client.println("<h1>ESP8266 BMP180 web server</h1>");
client.println("<font color=\"#6a5acd\"><body bgcolor=\"#a0dFfe\"><meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0, user-scalable=yes\">\n</div>\n<div style=\"clear:both;\"></div><p>");
client.println("<p id=\"switch_txt\">BMPSTATUS/p>");
client.println("<p>Example Display of BMP data</p>");
client.println("<p><a href=\"http://www.esp8266.com\">ESP8266 Support Forum</a></p>");
client.println("</body>");
client.println("</html>");
}
// Serial.print(HTTP_req);
HTTP_req = "";
break;
}
}
}
delay(1);
client.stop();
}
}
double getPressure()
{
char status;
double T,P,p0,a;
// You must first get a temperature measurement to perform a pressure reading.
// Start a temperature measurement:
// If request is successful, the number of ms to wait is returned.
// If request is unsuccessful, 0 is returned.
status = pressure.startTemperature();
if (status != 0)
{
// Wait for the measurement to complete:
delay(status);
// Retrieve the completed temperature measurement:
// Note that the measurement is stored in the variable T.
// Use '&T' to provide the address of T to the function.
// Function returns 1 if successful, 0 if failure.
status = pressure.getTemperature(T);
if (status != 0)
{
// Start a pressure measurement:
// The parameter is the oversampling setting, from 0 to 3 (highest res, longest wait).
// If request is successful, the number of ms to wait is returned.
// If request is unsuccessful, 0 is returned.
status = pressure.startPressure(3);
if (status != 0)
{
// Wait for the measurement to complete:
delay(status);
// Retrieve the completed pressure measurement:
// Note that the measurement is stored in the variable P.
// Use '&P' to provide the address of P.
// Note also that the function requires the previous temperature measurement (T).
// (If temperature is stable, you can do one temperature measurement for a number of pressure measurements.)
// Function returns 1 if successful, 0 if failure.
status = pressure.getPressure(P,T);
if (status != 0)
{
return(P);
}
else Serial.println("error retrieving pressure measurement\n");
}
else Serial.println("error starting pressure measurement\n");
}
else Serial.println("error retrieving temperature measurement\n");
}
else Serial.println("error starting temperature measurement\n");
}
void getTemperature(WiFiClient cl) {
char status;
double T,a,P;
P = getPressure();
a = pressure.altitude(P,baseline);
pressure.getTemperature(T);
status = pressure.startTemperature();
if (status != 0)
{
// Wait for the measurement to complete:
delay(status);
// Retrieve the completed temperature measurement:
// Note that the measurement is stored in the variable T.
// Function returns 1 if successful, 0 if failure.
}
status = pressure.getTemperature(T);
cl.print("Temperature: ");
cl.print(T);
cl.print(" C");
cl.print("<BR>Absolute Pressure: ");
cl.print(P,2);
cl.print(" mb");
cl.print(" - ");
cl.print(P*0.0295333727,2);
cl.print(" inHg");
cl.print("<BR>Relative Altitude: ");
cl.print(a,0);
cl.print(" meters above Start Position ( ");
cl.print(a*3.28084,0);
cl.print(" Feet for OLD Git's)");
}