I have a spark core which is connects to Ubidots.com, a web service that records sensor states. It's working! I'm getting 1 and 0 for the closed/open door. But, I think I need to better understanding of some of the errors I have seen while setting this up and what they mean. In addition, the app could fail to record anything if the door is opened and closed very quickly! Here are my observations and questions.:
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If I try to flash new code via build.spark.io it frequently fails with a timeout error. If I try over and over it later randomly works. How do I get it to work the first time? What is causing the timeout? (the cyan light is "breathing" when start the flash attempt)
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Some of the time the led on spark core turns red then back to cyan. It is hard to count the number of red flashes as it turns red like this at seemingly random intervals. (though it happens most often after resetting or managing to flash new firmware. I think there are between 4-8 red flashes. It turns red less and less often the longer I run it, eventually after about an hour it never turns red again until the next re-boot. So, it seems to stabilize. Is this something to worry about?
PANIC CODES number of red flashes: 1 Hard fault 2 Non-mask interrupt fault 3 Mem Manager fault 4 Bus fault 5 Usage fault 6 Invalid length 7 Exit 8 Out of heap memory 9 SPI over-run 10 Assertion failure 11 invalid case 12 Pure virtual call
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The app is slow to respond (as indicated by the led turning on) to the door being opened. I worry my app would miss if the door was opened and closed quickly. Can I fix this by reducing the delay? Isn't it bad to have quickly looping code or a short delay?
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Is there a way to record when the door is opened and closed where the sensor triggers the variable to update instead of this constant checking of the analog input over and over? (*I want an accurate list of all the approximate times the door was opened, I can do without super-fast instant updates about the current state of the door.)
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What about sending data to ubidots.com only when there is a change? Is it worthwhile to write code check for a change before allowing it to POST?
OK here is my code. How can I make it better?
Code, Trimmed to the Best of my Abilities.
// ---------------------------------------------------
// ---------------------------------------------------
// This app will check the open door sensor as
// an analog input (0-4095). High values mean
// the contacts are separated (i.e. the door is
// open). Low values mean the door is closed
// or "almost closed."
//
// I assign: 1 for closed
// 0 for open to the variable doorStat.
//
// Then we send the variable doorStat to
// Ubidots.com, a web-based sensor data
// collection service.
// ---------------------------------------------------
// include HTTP library to connect to Ubidots.com,
// define Ubidots variable(s) and token.
#include "HttpClient/HttpClient.h"
HttpClient http;
#define VARIABLE_ID "123myVariableIDFromUbidots"
#define TOKEN "abcd12345myTokenFromUbidots"
// Ubidots: Headers currently need to be set at
// init, useful for API keys etc.
http_header_t headers[] = {
{ "Content-Type", "application/json" },
{ "X-Auth-Token" , TOKEN },
{ NULL, NULL } // NOTE: Always terminate headers with NULL
};
http_request_t request;
http_response_t response;
// Declare a variable used to send data to Ubidots
char resultstr[64];
// Create a variable that will store 0 for closed,
// 1 for open. (Default value, 0)
float doorStat = 0;
// Create a variable to store analog sensor data
// before processing it
int reading = 0;
void setup() {
// Initialize D0 pin, an led, as output
pinMode(D0, OUTPUT);
// Initialize A7 pin, door sensor as input
pinMode(A7, INPUT);
request.hostname = "things.ubidots.com";
request.port = 80;
}
void loop() {
// Get variable using sensor
reading = analogRead(A7);
// The returned value from the core is
// going to be in the range from 0 to 4095
// Based on the reading assign 1 or 0 to
// doorStat and turn the LED on or off.
if (reading < 400) {
doorStat = 1; //assign 1 for "door closed"
digitalWrite(D0, LOW); // Turn OFF the LED pins
} else {
doorStat = 0; //assign 0 for "door open"
digitalWrite(D0, HIGH); // Turn ON the LED pins
}
// Send doorStat to Ubidots.
// Should this run only when doorStat changed?
request.path = "/api/v1.6/variables/"VARIABLE_ID"/values";
sprintf(resultstr, "{\"value\":%.4f}",doorStat);
request.body = resultstr;
http.post(request, response, headers);
delay(1000); //What are the issues with a shorter delay?
}
