Published November 16, 2017 © GPL3+

Temperature Sensor - UNCC MEGR 3171 Fall 2017

Always be prepared for the outdoors. Find out the exact temperature outside your home without the need to open a weather app or go outside!

IntermediateFull instructions provided4 hours1,721

Temperature Sensor - UNCC MEGR 3171 Fall 2017

Things used in this project

Hardware components

Particle Photon

USB-A to Micro-USB Cable

Breadboard (generic)

Resistor 4.75k ohm

Jumper wires (generic)

Temperature Sensor

DS18B20 Model

Adafruit SSD1306 OLED Display

Software apps and online services

Particle DEV

IFTTT Maker service

Google Sheets

Story

Background

Being that it is fall, and in the state of North Carolina, you never know what the weather is going to be like at the start of each day. We created this IOT project with the goal of being able to know the temperature outside your home/office without the need of looking at a weather app or checking an outside thermometer. To accomplish this, two Particle Photons were used. The first was connected to a temperature sensor, which would record the present temperature and publish to the internet. The second Photon was connected to a OLED display, which was subscribed to the data published by the first Photon, and would display the current temperature on the display for the user to see.

How it works - Temperature Sensor

The first Photon, referenced as Temperature Sensor in the wiring diagram and code attachment, was responsible for recording the temperature and then publish the temperature data to the internet. The photon was set to record the temperature every 30 minutes. To test the sensor, we placed the photon outside and allowed it to record and publish data for a 24 hour period, starting at 1:00 PM on November 1 and ending at 1:00 PM the next day. IFTTT was paired with the Photon over this period so that Google Sheets could be used to plot the temperature versus the time it was recorded. Through this graph, you can see that the peak temperature is 2 hours into testing (3 PM) and that the minimum temperature occurs 18.5 hours into testing (7:30 AM, just before sunrise). Below is the Google Sheets graph displaying the temperature data over this time period. Note that the Temperature Sensor code includes library codes "OneWire.h" and "spark-dallas-temperature.h".

Temperature variation over 24 hour period

How it Works - Temperature Display

The second Photon, referenced as Temperature Display in the wiring diagram and code attachment, was what would show the user the live temperature being recorded from the other Photon. After the first Photon began publishing data, this Photon simply subscribed to the first Photon, and displayed the temperature recorded until a new temperature was taken 30 minutes later. Note that the Temperature Display code includes library codes "Adafruit_SSD1306/Adafruit_GFX.h" and "Adafruit_SSD1306/Adafruit_SSD1306.h".

Temperature Display (bottom) showing Temperature Sensor (top) data

Demonstration of Project

Code

/*********************************************************************
This is an example for our Monochrome OLEDs based on SSD1306 drivers

  Pick one up today in the adafruit shop!
  ------> http://www.adafruit.com/category/63_98

This example is for a 128x64 size display using SPI to communicate
4 or 5 pins are required to interface

Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!

Written by Limor Fried/Ladyada  for Adafruit Industries.
BSD license, check license.txt for more information
All text above, and the splash screen must be included in any redistribution
*********************************************************************/

#include "Adafruit_SSD1306/Adafruit_GFX.h"
#include "Adafruit_SSD1306/Adafruit_SSD1306.h"

/* Uncomment this block to use hardware SPI
// If using software SPI (the default case):
#define OLED_MOSI   D0
#define OLED_CLK    D1
#define OLED_DC     D2
#define OLED_CS     D3
#define OLED_RESET  D4
Adafruit_SSD1306 display(OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);
*/

// use hardware SPI
#define OLED_DC     D3
#define OLED_CS     D4
#define OLED_RESET  D5
Adafruit_SSD1306 display(OLED_DC, OLED_RESET, OLED_CS);


#define NUMFLAKES 10
#define XPOS 0
#define YPOS 1
#define DELTAY 2



#define LOGO16_GLCD_HEIGHT 16
#define LOGO16_GLCD_WIDTH  16

static const unsigned char logo16_glcd_bmp[] =
{ 0B00000000, 0B11000000,
  0B00000001, 0B11000000,
  0B00000001, 0B11000000,
  0B00000011, 0B11100000,
  0B11110011, 0B11100000,
  0B11111110, 0B11111000,
  0B01111110, 0B11111111,
  0B00110011, 0B10011111,
  0B00011111, 0B11111100,
  0B00001101, 0B01110000,
  0B00011011, 0B10100000,
  0B00111111, 0B11100000,
  0B00111111, 0B11110000,
  0B01111100, 0B11110000,
  0B01110000, 0B01110000,
  0B00000000, 0B00110000 };

#if (SSD1306_LCDHEIGHT != 64)
#error("Height incorrect, please fix Adafruit_SSD1306.h!");
#endif

//Get Temperature data from cloud
void tempF(const char *JtwoguysonecodeF, const char *dataF)
{
  // display the temperature
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(0,0);
  display.printlnf("%s Fahrenheit\n", dataF, 3);
  display.display();
  display.clearDisplay(); // clears the screen and buffer
}

void setup()   {
  Serial.begin(9600);

  // by default, we'll generate the high voltage from the 3.3v line internally! (neat!)
  display.begin(SSD1306_SWITCHCAPVCC);
  // init done
  display.display(); // show splashscreen
  delay(100);
  display.clearDisplay();  // clears the screen and buffer

  // Subscribe to tempearture variable
  Particle.subscribe("JtwoguysonecodeF", tempF);

}

// This #include statement was automatically added by the Spark IDE.
#include "OneWire.h"

// This #include statement was automatically added by the Spark IDE.
#include "spark-dallas-temperature.h"

// -----------------
// Read temperature
// -----------------

// Data wire is plugged into port 0 on the Photon
// Setup a oneWire instance to communicate with any OneWire devices (not just Maxim/Dallas temperature ICs)
OneWire oneWire(D0 );

// Pass our oneWire reference to Dallas Temperature.
DallasTemperature dallas(&oneWire);

// Create a variable that will store the temperature value
double temperature = 0.0;
double temperatureF = 0.0;

void setup()
{
  // Register Particle variables
  Particle.variable("temperature", &temperature, DOUBLE);
  Particle.variable("temperatureF", &temperatureF, DOUBLE);

  // setup the library
  dallas.begin();
}

void loop()
{

  // Request temperature conversion
  dallas.requestTemperatures();

  // get the temperature in Celcius
  float tempC = dallas.getTempCByIndex(0);
  //Filter out voltage spikes
  if (tempC < -50) {
      //The below statement leaves tempC as is if the sensor reports < -50C
      tempC = tempC;
      delay(1000);
    }
    else
    {
      // convert to double
      temperature = (double)tempC;
    }

  // convert to Fahrenheit
  float tempF = DallasTemperature::toFahrenheit( tempC );
  //Filter out voltage spikes
  if (tempF < -50) {
      //The below statement leaves tempC as is if the sensor reports < -50C
      tempF = tempF;
      delay(1000);
    }
    else
    {
      // convert to double
      temperatureF = (double)tempF;
    }

  // Publish Particle Variable
  Particle.publish("Jtwoguysonecode", String(temperature));
  Particle.publish("JtwoguysonecodeF", String(temperatureF));

  //Delay 5 seconds
  delay(5000);

}

/*
The API request will look something like this:
GET /v1/devices/{DEVICE_ID}/temperature

# EXAMPLE REQUEST IN TERMINAL
# Device ID is 0123456789abcdef
# Your access token is 123412341234
curl -G https://api.particle.io/v1/devices/0123456789abcdef/temperature \
  -d access_token=123412341234
*/

Credits

Jerry Autry

1 project • 1 follower

UNCC Mechanical Engineering Student

Douglas Lawrence

1 project • 1 follower

Temperature Sensor - UNCC MEGR 3171 Fall 2017