Pete Hoffswell
Published © CC BY-NC-SA

Multiple Sensors: Particle Photon + ThingSpeak

Read multiple sensors from a Particle Photon and Publish via webhook to Thingspeak.

EasyFull instructions provided2 hours4,419
Multiple Sensors: Particle Photon + ThingSpeak

Things used in this project

Hardware components

Photon
Particle Photon
×1
DHT11 Temperature & Humidity Sensor
DHT11 Temperature & Humidity Sensor
×1
Photo resistor
Photo resistor
×1
Resistor 10k ohm
Resistor 10k ohm
×1
Resistor 330 ohm
Resistor 330 ohm
Or 220 ohm. I think this is a pull-down resistor, isn't it?
×1
Breadboard (generic)
Breadboard (generic)
×1

Software apps and online services

particle.io Build online IDE
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ThingSpeak Open Data Platform
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Story

Read more

Schematics

Circuit

Here's the whole circuit -
Solar1

Code

Particle.io Webhook

JSON
This is the code that resides at particle.io. No changes are required.
{
    "event": "thingSpeakWrite_",
    "url": "https://api.thingspeak.com/update",
    "requestType": "POST",
    "form": {
        "api_key": "{{k}}",
        "field1": "{{1}}",
        "field2": "{{2}}",
        "field3": "{{3}}",
        "field4": "{{4}}",
        "field5": "{{5}}",
        "field6": "{{6}}",
        "field7": "{{7}}",
        "field8": "{{8}}",
        "lat": "{{a}}",
        "long": "{{o}}",
        "elevation": "{{e}}",
        "status": "{{s}}"
    },
    "mydevices": true,
    "noDefaults": true
}

solarmonitor.ino

C#
// This #include statement was automatically added by the Particle IDE.
#include "Adafruit_DHT/Adafruit_DHT.h"

// -----------------------------------------
// solarmonitor
// Monitor light, temperature and Humidy at solar panel
// Particle Photon + Particle.io Webhook + ThingSpeak Integration
// April, 2016 - Pete Hoffswell - pete@hoffswell.com
// -----------------------------------------

#define DHTPIN 2
#define DHTTYPE DHT11 // DHT11 Module

#define publish_cycle 60000 // Only publish every 60 seconds
const String key = "8OAB88505K78478J"; // Change this to your Thingspeak api write key

int led = D7; // Sensor Read Light
int photoCell = A0;
int power = A5; // Photocell power.  An analog pin to gives a more steady voltage.

int light; // Light
double tempF; // Temperature F
double tempC; // Temperature C
double humidity; // Humidity
unsigned int lastPublish = 0;

DHT dht(DHTPIN, DHTTYPE);

void setup() {
    // Set Pin Modes
    pinMode(led,OUTPUT);
    pinMode(photoCell,INPUT);
    pinMode(power,OUTPUT);

    digitalWrite(power,HIGH); // Turn on power source for photoCell
    digitalWrite(led,LOW); 

    // Connect variables to particle cloud
    // This allows you to save data to particle.io, and run commands against it such as "particle variable Photon get light"
    Particle.variable("light", &light, INT);
    Particle.variable("tempF", &tempF, DOUBLE);
    Particle.variable("tempC", &tempC, DOUBLE);
    Particle.variable("humidity", &humidity, DOUBLE);

    dht.begin();
    Serial.begin(9600);
    delay(10000);

} //setup


void loop() {
  unsigned long now = millis();
  digitalWrite(led,HIGH); // Signal read sequence led

  // read sensors
  light = analogRead(photoCell);
  delay(100);  // is this needed?
  humidity = dht.getHumidity();
  tempC = dht.getTempCelcius();
  tempF = dht.getTempFarenheit();

  // DHT Read ok?
  if (isnan(humidity) || isnan(tempF) || isnan(tempC)) {
    Serial.println("");
    Serial.println("Failed to read from DHT sensor!");
    Serial.println("humidity=" + String(humidity) + " tempF=" + String(tempF) + " tempC=" + String(tempC));
    Serial.println("");
    return; // exit loop and try again
  }

  // Display to serial
  Serial.println();
  Serial.print("humidity=" + String(humidity) + " tempF=" + String(tempF) + " tempC=" + String(tempC) + " light=" + String(light));
  delay(200);

  // Publish to thinkspeak
  if ((now - lastPublish) > publish_cycle) {
    Particle.publish("thingSpeakWrite_All", "{ \"1\": \"" + String(humidity) + "\"," +
       "\"2\": \"" + String(tempC) + "\"," +
       "\"3\": \"" + String(tempF) + "\"," +
       "\"4\": \"" + String(light) + "\"," +
       "\"k\": \"" + key + "\" }", 60, PRIVATE);
    lastPublish = now;
    Serial.println(" - Published!");
  } else {
      Serial.println();
  }

  digitalWrite(led,LOW);
  delay(2000); // Wait 2 seconds before next loop
  
} // loop

Credits

Pete Hoffswell

Pete Hoffswell

10 projects • 52 followers
Network Engineer for All the People. Internet advocate. Microcontroller Fan. Maker.
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