Cosm example with temp and humidity sensor (DHT11) added - arduino

Question

Added a temperature and humidity sensor (DHT11) to the standard Cosm Arduino sensor client example. Works for a short while then data streams flat line.
Any idea what could be causing the problem?
Many thanks
Staza
/**
* Cosm Arduino sensor client example.
*
`` * This sketch demonstrates connecting an Arduino to Cosm (https://cosm.com),
* using the new Arduino library to send and receive data.
/**
DHT11 temp and humidity sensor added to the COSM example code
**/
#include <SPI.h>
#include <Ethernet.h>
#include <HttpClient.h>
#include <Cosm.h>
#include <dht11.h>
//DHT11*********************************************************************
dht11 DHT11;
#define DHT11PIN 7//pin DHT11 sensor is connected to
//DHT11*********************************************************************
#define API_KEY "xxxxxx" // your Cosm API key
#define FEED_ID xxxxx // your Cosm feed ID
// MAC address for your Ethernet shield
byte mac[] = {xxxx, xxxx, xxxx, xxxx, xxxx, xxxx};
// Analog pin which we're monitoring (0 and 1 are used by the Ethernet shield)
int sensorPin = 2;
unsigned long lastConnectionTime = 0; // last time we connected to Cosm
const unsigned long connectionInterval = 15000; // delay between connecting to Cosm in milliseconds
// Initialize the Cosm library
// Define the string for our datastream ID
char sensorId[] = "sensor_reading";
char sensorId2[] = "DHT11_humidity_sensor_reading";
char sensorId3[] = "DHT11_temperature_sensor_reading";
CosmDatastream datastreams[] = {
CosmDatastream(sensorId, strlen(sensorId), DATASTREAM_FLOAT),
CosmDatastream(sensorId2, strlen(sensorId2), DATASTREAM_FLOAT),
CosmDatastream(sensorId3, strlen(sensorId3), DATASTREAM_FLOAT),
};
// Wrap the datastream into a feed
CosmFeed feed(FEED_ID, datastreams, 3 /* number of datastreams */);
EthernetClient client;
CosmClient cosmclient(client);
void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
Serial.println("Cosm Sensor Client Example");
Serial.println("==========================");
Serial.println("Initializing network");
while (Ethernet.begin(mac) != 1) {
Serial.println("Error getting IP address via DHCP, trying again...");
delay(15000);
}
Serial.println("Network initialized");
Serial.println();
}
void loop() {
// main program loop
if (millis() - lastConnectionTime > connectionInterval) {
//check DHT11 sensor is working OK
int chk = DHT11.read(DHT11PIN);
Serial.print("Read DHT11 sensor: ");
switch (chk)
{
case 0: Serial.println("OK"); break;
case -1: Serial.println("Checksum error"); break;
case -2: Serial.println("Time out error"); break;
default: Serial.println("Unknown error"); break;
}
sendData(); // send data to Cosm
getData(); // read the datastream back from Cosm
lastConnectionTime = millis(); // update connection time so we wait before connecting again
}
}
// send the supplied values to Cosm, printing some debug information as we go
void sendData() {
int sensorValue = analogRead(sensorPin);
int humidityDHT11 = ((float)DHT11.humidity);
int tempDHT11 = ((float)DHT11.temperature);
datastreams[0].setFloat(sensorValue);
datastreams[1].setFloat(humidityDHT11); //DHT11 humidity value*******
datastreams[2].setFloat(tempDHT11); //DHT11 temp value********
Serial.print("Read sensor value ");
Serial.println(datastreams[0].getFloat());
Serial.print("Read DHT11 humidity sensor value ");
Serial.println(datastreams[1].getFloat());
Serial.print("Read DHT11 temperature sensor value ");
Serial.println(datastreams[2].getFloat());
Serial.println("Uploading to Cosm");
int ret = cosmclient.put(feed, API_KEY);
Serial.print("PUT return code: ");
Serial.println(ret);
Serial.println();
}
// get the value of the datastream from Cosm, printing out the value we received
void getData() {
Serial.println("Reading data from Cosm");
int ret = cosmclient.get(feed, API_KEY);
Serial.print("GET return code: ");
Serial.println(ret);
if (ret > 0) {
Serial.print("Datastream is: ");
Serial.println(feed[0]);
Serial.print("Sensor value is: ");
Serial.println(feed[0].getFloat());
Serial.print("Datastream is: ");
Serial.println(feed[1]);
Serial.print("Sensor value is: ");
Serial.println(feed[1].getFloat());
Serial.print("Datastream is: ");
Serial.println(feed[2]);
Serial.print("Sensor value is: ");
Serial.println(feed[2].getFloat());
}
Serial.println();
}

Answer 1

Cosm has a debug page which might give you a clue as to what's going wrong.
This is currently located at: https://cosm.com/users/YOURUSERNAME/debug and it lists all incoming requests in real time as they come through. If your device works initially, you should see it start making requests successfully, and depending on how long it takes till it flatlines you might be able to keep this page open and hopefully see when it starts failing.
Do you see anything in the Arduino serial output when it seems to stop working, or does it seem like the Arduino is still happily sending data?
The other thing you could try is using Wireshark to inspect network traffic over the wire. Setting this up is slightly more involved however, so I'd suggest trying the other approaches first.
If none of this seems feasible I'd suggest mailing Cosm support with your feed details and have them look into it.

Answer 2

Seconding smulube's suggestion to monitor the serial output. Additionally, eliminate the variable of the COSM code & Ethernet: start debugging the issue with a sketch that is just taking readings from the DHT11 and monitor what's going on in the Arduino's serial output on your computer (in the Tools dropdown menu).
I just received my DHT22 (RHT03) from Sparkfun last night and tried several samples that wouldn't compile (my fault, I'm sure). The sample that worked "out of the box" for me with my Arduino Uno came from Tom Boyd's page (be sure to scroll to the bottom for the most recent code): DHT11 / Aosong AM2302 humidity and temperature sensor
I'm curious: how long did it take for your sensor to flatline? I integrated the code from Tom with the Cosm code and it's been running without interruption for me for an hour now.
Cheers,
Reeves