GET reads all return same variable value

Cloud
1

I’m trying to read a variable value using the Cloud API, but everything I read seems to come back as the same raw value of " P". Any idea as to why?

https://api.spark.io/v1/devices//counter1?access_token=(will change token at a later date, try now for troubleshooting)

Code:

int counter1 = 0;
int counter2 = 53;
    
void setup() {
    pinMode(D2, OUTPUT);
}

void loop() {
    digitalWrite(D2, HIGH);
    delay(250);
    digitalWrite(D2, LOW);
    delay(1000);
    
   counter1++;
   counter2++;

}

Response:

{
cmd: "VarReturn"
name: "counter1"
TEMPORARY_allTypes: {
string: " P"
uint32: 536891392
number: 536891392
double: null
float: 1.0868491504456741e-19
raw: " P"
}-
result: " P"
coreInfo: {
last_app: ""
last_heard: "2014-01-05T19:39:03.987Z"
connected: true
deviceID: "53ff67065067544825071287"
}-
}

If you check that URL out in a browser, the raw value actually seems to be " \u0000P\u0000"… the app I’m using to format GET/POST requests formats the unicode I guess.

Why does the GET not return the proper value of counter1 or counter2?

2

You need to add these two lines to your setup()

Spark.variable("counter1",&counter1,INT);
Spark.variable("counter2",&counter2,INT);

Should work after that :wink:

Also if you ever see that string: " P" you know you have an error in how you are trying to read the variable. It should probably give you an error and say that the requested varKey is undefined

3

Ugh… the learning, it hurts so good! This has probably been asked a million times, but is there a section of documentation that contains this particular feature? I can’t shake the feeling that I’m missing something huge.

Thanks a ton for the pointer :smile:

4

No problem! Here’s a link to the Core Firmware Reference:
http://docs.spark.io/#/firmware/cloud-spark-variable

5

Holy… yep, missed those examples. You guys rock, thanks again!

6

So… uh… do float values work?

Code:

float h;    // humidity

Setup:

Spark.variable("h",&h,FLOAT);

Error:

error: 'FLOAT' was not declared in this scope
7

Nope, but DOUBLE will compile… however won’t give you a valid value yet from the cloud. A fix is in the works!

For now you can do this, and send you DOUBLE or FLOAT as a string:

double temperature = 1.0;
char myStr[10];

void setup() {
  Spark.variable("read", &myStr, STRING);
}

void loop() {
  temperature += 0.5;
  sprintf(myStr,"%.2f",temperature);
  delay(500);
}
8

Absolutely beautiful. Humidor Tweetbox 1.0-beta complete! Many thanks :smiley: