Thanks to all of you who helped me in Getting Started. I’ve learned a lot.
I got my project to work with Blynk, but figured a web page might be more robust, so I’ve spent the last two days trying to get a variable passed to a web page and just can’t get it to work. I guess this is really an html/java question. (Two brand new areas to me.)
I have been working through Simon Monk’s “Getting Started . . .” book and got the Project 9 Measuring Light over the Internet to work. Using my Maxbotix EZ on A0 to generate voltages that read out on the dial graph instead of the light sensor in his example. It worked. 
Now I want to actually get my Percent Full variable passed and it just won’t get there.
Here is my sketch with my Particle.variable line pretty much matching his:
// This #include statement was automatically added by the Particle IDE.
#include <Particle.h>
double emptydepth = 67.0; //Depth of tank in inches
int maxbotix = A0; // This is the Maxbotix Analog Data out.
int analogvalue = 0; // Declaring the integer variable analogvalue, which we will use later to store the value from the Maxbotix.
int range = 0; //Declaring a variable that will be the calulated range in inches
int percentfull = 0; //Variable to hold % full
float Vin = 3.3; // Using 3.3 V from the Battery Shield
float constant = (3.3 / 4095) / (Vin / 512); // changed from 1024 to 512 for Max EZ
//NOTE: New WR7060 reads in cm => Vcc/1024 per cm
int correction = 8; // gap from the sensor to the top of the water in a full tank. Used in the map() function
// Next we go into the setup function.
void setup() {
pinMode(maxbotix,INPUT); // reading the Maxbotix)
Serial.begin(9600);
**Particle.variable("Full", &percentfull);**
}
// Next is the loop function...
void loop() {
analogvalue = analogRead(maxbotix);
range = analogvalue * constant;
if (range <= emptydepth) {
percentfull = map(range, 8, emptydepth, 100, 0);
}
// Added to account for screwy readings when targe is very close to sensor
if (range > emptydepth) { //
percentfull = 100;
}
//Particle.publish("% Full", String(percentfull));
Serial.print("% Full = ");
Serial.println(percentfull);
}
I added the Serial.print to be sure it was working and it did put out accurate values to the terminal. I also tried it both with and without the Particle.publish() line. With it in, it did show on the console.
One thing that confuses me in his example is he uses “volts” as the variable name to be passed and “volts” as the variable in the Photon sketch. I think once the variable gets passed under its name (in my case “Full”) it can become “percentfull” in the html code by the “percentfull=parseFloat(data.result)” line - no?
Here is the html copied almost verbatim from Monk:
<html>
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"
type="text/javascript" charset="utf-8"></script>
<script src="R:/My Documents/Particle/html stuff/justgage-1.2.2/justgage-1.2.2/raphael-
2.1.4.min.js"></script>
<script src="R:/My Documents/Particle/html stuff/justgage-1.2.2/justgage-
1.2.2/justgage.js"></script>
<script>
<!-- Only changes are my values below -->
var accessToken = "My Access Token";
var deviceID = "My Device ID"
<!-- spark or particle ?? Book example worked with spark-->
var url = "https://api.particle.io/v1/devices/" + deviceID + "/Full";
function callback(data, status){
if (status == "success") {
<!--volts = parseFloat(data.result);-->
percentfull = parseFloat(data.result);
<!--volts = volts.toFixed(2);-->
percentfull = percentfull.toFixed(0);
g.refresh(percentfull);
setTimeout(getReading, 1000);
}
else {
alert("There was a problem");
}
}
function getReading(){
$.get(url, {access_token: accessToken}, callback);
}
</script>
</head>
<body>
<div id="gauge" class="200x160px"></div>
<script>
var g = new JustGage({
id: "gauge",
value: 0,
min: 0,
max: 100,
title: "% Full"
});
getReading();
</script>
</body>
</html>
When I run it I get the gauge showing, but NaN under it. Also when I run:
"https://api.particle.io/v1/devices/My Device/Full?access_token=My token"
I get: {"cmd":"VarReturn","name":"Full"**_,"result":true,"_**coreInfo":{"last_app":"","last_heard":"2017-04-01T22:32:23.288Z","connected":true,"last_handshake_at":"2017-04-01T22:30:54.824Z","deviceID":"2a0046001247353136383631","product_id":6}}
NaN is “Not a number” (not sure why I’m getting that) and that kind of fits why I’m getting a result of “true” rather than a value, but I just can’t see why his example works and mine doesn’t.
I would really appreciate it if, with your experienced eyes, you could point me in the right direction.
THANK YOU!
Watching “percentfull” on the serial port it cranks out numbers just fine. I guess I need to do some more digging on particle.variable.
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