Eric AndersonPatrick SwangerCarter Daley
Published

Temperature Controlled Attic Fan

Using the the relative temperatures between two sensors to control an attic fan in order to improve the efficiency of your home's AC.

Intermediate3 hours974
Temperature Controlled Attic Fan

Things used in this project

Hardware components

Photon
Particle Photon
×3
DS18B20 Programmable Resolution 1-Wire Digital Thermometer
Maxim Integrated DS18B20 Programmable Resolution 1-Wire Digital Thermometer
×2
SparkFun 4.7 Ohm resistor
×4
Es08A II Analog Servo
×1
Solderless Breadboard Half Size
Solderless Breadboard Half Size
×2
4xAA battery holder
4xAA battery holder
×3
AA Batteries
AA Batteries
×12
Male/Male Jumper Wires
×12
3 mm LED: Red
3 mm LED: Red
×1
3 mm LED: Yellow
3 mm LED: Yellow
×1
3 mm LED: Green
3 mm LED: Green
×2
White LED
×2
Solderless Breadboard Full Size
Solderless Breadboard Full Size
×1

Software apps and online services

Maker service
IFTTT Maker service
Three separate IFTTT applets were used. Two update cells in a google spreadsheet. These values are used to calculate a response, which is read by a third applet that then publishes a particle event.
Google Sheets
Google Sheets
The google spreadsheet acts as the hub for the whole operation. It calculates the temperature difference and compares this to a user input difference value. An "IF" statement is used to change the value of a cell, which is read by an IFTTT applet.

Story

Read more

Schematics

Fan Control Photon Wiring Diagram

This depicts the set up for the fan control. The photon can be powered by USB or by use of a 4 AA battery pack with the red wire going to Vin and black wire going to GND.

Temperature Sensing Photon Wiring Diagram

This depicts the set up for the temperature sensing photons. The set up is exactly the same for both sensors. The photon can be powered by USB or by using a 4 AA battery pack with the red wire going to Vin and black wire going to GND.

Code

Temperature Sensor #1

C/C++
This is the photon code used to program one of the temperature sensors. It is intended to take a temperature reading and publish it to the cloud. It will also be notified when another temperature sensor takes a reading and will illuminate a status LED as a result. Additionally it will be notified of an event when an attic fan is switched on and illuminate a status LED for the duration that it is powered on. It can be copied and pasted into the particle web IDE for use.
/*this program is intened to take a temperature reading and publish it to the cloud. It will also
be notified when another temperature sensor takes a reading and illuminate a status LED as a result. 
Additionally it will be notified of an event when an attic fan is switched on and illuminate a status
LED for the duration that it is powered on.*/

// This #include statement was automatically added by the Particle IDE.
#include <OneWire.h>



/************************************************************************
This sketch reads the temperature from a 1-Wire device and then publishes
to the Particle cloud. From there, IFTTT can be used to log the date,
time, and temperature to a Google Spreadsheet. Read more in our tutorial
here: https://docs.particle.io/tutorials/topics/maker-kit

This sketch is the same as the example from the OneWire library, but
with the addition of three lines at the end to publish the data to the
cloud.

Use this sketch to read the temperature from 1-Wire devices
you have attached to your Particle device (core, p0, p1, photon, electron)

Temperature is read from: DS18S20, DS18B20, DS1822, DS2438

Expanding on the enumeration process in the address scanner, this example
reads the temperature and outputs it from known device types as it scans.

I/O setup:
These made it easy to just 'plug in' my 18B20 (note that a bare TO-92
sensor may read higher than it should if it's right next to the Photon)

D3 - 1-wire ground, or just use regular pin and comment out below.
D4 - 1-wire signal, 2K-10K resistor to D5 (3v3)
D5 - 1-wire power, ditto ground comment.

A pull-up resistor is required on the signal line. The spec calls for a 4.7K.
I have used 1K-10K depending on the bus configuration and what I had out on the
bench. If you are powering the device, they all work. If you are using parisidic
power it gets more picky about the value.
************************************************************************/

OneWire ds = OneWire(D4);  // 1-wire signal on pin D4

unsigned long lastUpdate = 0;

float lastTemp;
int status0 = D0;
int status1 = D1;

void setup() {
  Serial.begin(9600);
  // Set up 'power' pins, comment out if not used!
  pinMode(status0, OUTPUT);
  pinMode(status1, OUTPUT);
  
  Particle.subscribe("status_eanderson", StatusLight); //subscribe to the event of the fan switching on and off
  Particle.subscribe("temperature_swanger", templed); //subscribe to the event when the other sensor takes a reading
 //illuminate each of the status LED to show that setup has complete
  digitalWrite(status0, HIGH);
  delay(500);
  digitalWrite(status0, LOW);
  delay(500);
  digitalWrite(status1, HIGH);
  delay(500);
  digitalWrite(status1, LOW);
  delay(500);
  
}

//the following portion of the code was taken from the maker kit tutorial "tutorial #4: temperature logger" to set up the temperature sensor

// up to here, it is the same as the address acanner
// we need a few more variables for this example

void loop(void) {
  byte i;
  byte present = 0;
  byte type_s;
  byte data[12];
  byte addr[8];
  float celsius, fahrenheit;

  if ( !ds.search(addr)) {
    Serial.println("No more addresses.");
    Serial.println();
    ds.reset_search();
    delay(250);
    return;
  }

  // The order is changed a bit in this example
  // first the returned address is printed

  Serial.print("ROM =");
  for( i = 0; i < 8; i++) {
    Serial.write(' ');
    Serial.print(addr[i], HEX);
  }

  // second the CRC is checked, on fail,
  // print error and just return to try again

  if (OneWire::crc8(addr, 7) != addr[7]) {
      Serial.println("CRC is not valid!");
      return;
  }
  Serial.println();

  // we have a good address at this point
  // what kind of chip do we have?
  // we will set a type_s value for known types or just return

  // the first ROM byte indicates which chip
  switch (addr[0]) {
    case 0x10:
      Serial.println("  Chip = DS1820/DS18S20");
      type_s = 1;
      break;
    case 0x28:
      Serial.println("  Chip = DS18B20");
      type_s = 0;
      break;
    case 0x22:
      Serial.println("  Chip = DS1822");
      type_s = 0;
      break;
    case 0x26:
      Serial.println("  Chip = DS2438");
      type_s = 2;
      break;
    default:
      Serial.println("Unknown device type.");
      return;
  }

  // this device has temp so let's read it

  ds.reset();               // first clear the 1-wire bus
  ds.select(addr);          // now select the device we just found
  // ds.write(0x44, 1);     // tell it to start a conversion, with parasite power on at the end
  ds.write(0x44, 0);        // or start conversion in powered mode (bus finishes low)

  // just wait a second while the conversion takes place
  // different chips have different conversion times, check the specs, 1 sec is worse case + 250ms
  // you could also communicate with other devices if you like but you would need
  // to already know their address to select them.

  delay(1000);     // maybe 750ms is enough, maybe not, wait 1 sec for conversion

  // we might do a ds.depower() (parasite) here, but the reset will take care of it.

  // first make sure current values are in the scratch pad

  present = ds.reset();
  ds.select(addr);
  ds.write(0xB8,0);         // Recall Memory 0
  ds.write(0x00,0);         // Recall Memory 0

  // now read the scratch pad

  present = ds.reset();
  ds.select(addr);
  ds.write(0xBE,0);         // Read Scratchpad
  if (type_s == 2) {
    ds.write(0x00,0);       // The DS2438 needs a page# to read
  }

  // transfer and print the values

  
  Serial.print("  Data = ");
  Serial.print(present, HEX);
  Serial.print(" ");
  

  for ( i = 0; i < 9; i++) {           // we need 9 bytes
    data[i] = ds.read();
    Serial.print(data[i], HEX);
    Serial.print(" ");
  }
  Serial.print(" CRC=");
  Serial.print(OneWire::crc8(data, 8), HEX);
  Serial.println();

  // Convert the data to actual temperature
  // because the result is a 16 bit signed integer, it should
  // be stored to an "int16_t" type, which is always 16 bits
  // even when compiled on a 32 bit processor.
  int16_t raw = (data[1] << 8) | data[0];
  if (type_s == 2) raw = (data[2] << 8) | data[1];
  byte cfg = (data[4] & 0x60);

  switch (type_s) {
    case 1:
      raw = raw << 3; // 9 bit resolution default
      if (data[7] == 0x10) {
        // "count remain" gives full 12 bit resolution
        raw = (raw & 0xFFF0) + 12 - data[6];
      }
      celsius = (int)raw * 0.0625;
      break;
    case 0:
      // at lower res, the low bits are undefined, so let's zero them
      if (cfg == 0x00) raw = raw & ~7;  // 9 bit resolution, 93.75 ms
      if (cfg == 0x20) raw = raw & ~3; // 10 bit res, 187.5 ms
      if (cfg == 0x40) raw = raw & ~1; // 11 bit res, 375 ms
      // default is 12 bit resolution, 750 ms conversion time
      celsius = (int)raw * 0.0625;
      break;

    case 2:
      data[1] = (data[1] >> 3) & 0x1f;
      if (data[2] > 127) {
        celsius = (int)data[2] - ((int)data[1] * .03125);
      }else{
        celsius = (int)data[2] + ((int)data[1] * .03125);
      }
  }

  // remove random errors
  if((((celsius <= 0 && celsius > -1) && lastTemp > 5)) || celsius > 125) {
      celsius = lastTemp;
  }
  
  
  fahrenheit = celsius * 1.8 + 32.0;
  
  lastTemp = celsius;
  Serial.print("  Temperature = ");
  Serial.print(celsius);
  Serial.print(" Celsius, ");
  Serial.print(fahrenheit);
  Serial.println(" Fahrenheit");
  
  
  
  //if(fahrenheit > 75){
  {
  // now that we have the readings, we can publish them to the cloud
  String temperature =  String(fahrenheit); // store temp in "temperature" string
  Particle.publish("temperature_carter", temperature); // publish to cloud under event name "temperature_carter"
  delay(10000); // 10 second delay between readings
  }
 

    


}
void StatusLight(const char *event, const char *data) {
   if (strcmp(data,"ON")==0){ //when the fan switches on illuminate the green status LED
        digitalWrite(status0,HIGH);
   }
   else if (strcmp(data,"OFF")==0){ //when the fan switches off, turn off the status LED
    digitalWrite(status0,LOW);
        }
}

void templed(const char *event, const char *data) {
   if (data){ //illuminate the white status LED when the other sensor takes a reading
       digitalWrite(status1,HIGH);
       delay(5000); //illuminate for five seconds before turning off
       digitalWrite(status1,LOW);
   }
}
    

Temperature Sensor #2

C/C++
This is the photon code used to program one of the temperature sensors. It is intended to take a temperature reading and publish it to the cloud. It will also be notified when another temperature sensor takes a reading and will illuminate a status LED as a result. Additionally it will be notified of an event when an attic fan is switched on and illuminate a status LED for the duration that it is powered on. It can be copied and pasted into the particle web IDE for use.
/*this program is intened to take a temperature reading and publish it to the cloud. It will also
be notified when another temperature sensor takes a reading and illuminate a status LED as a result. 
Additionally it will be notified of an event when an attic fan is switched on and illuminate a status
LED for the duration that it is powered on.*/

// This #include statement was automatically added by the Particle IDE.
#include <OneWire.h>

/************************************************************************
This sketch reads the temperature from a 1-Wire device and then publishes
to the Particle cloud. From there, IFTTT can be used to log the date,
time, and temperature to a Google Spreadsheet. Read more in our tutorial
here: https://docs.particle.io/tutorials/topics/maker-kit

This sketch is the same as the example from the OneWire library, but
with the addition of three lines at the end to publish the data to the
cloud.

Use this sketch to read the temperature from 1-Wire devices
you have attached to your Particle device (core, p0, p1, photon, electron)

Temperature is read from: DS18S20, DS18B20, DS1822, DS2438

Expanding on the enumeration process in the address scanner, this example
reads the temperature and outputs it from known device types as it scans.

I/O setup:
These made it easy to just 'plug in' my 18B20 (note that a bare TO-92
sensor may read higher than it should if it's right next to the Photon)

D3 - 1-wire ground, or just use regular pin and comment out below.
D4 - 1-wire signal, 2K-10K resistor to D5 (3v3)
D5 - 1-wire power, ditto ground comment.

A pull-up resistor is required on the signal line. The spec calls for a 4.7K.
I have used 1K-10K depending on the bus configuration and what I had out on the
bench. If you are powering the device, they all work. If you are using parisidic
power it gets more picky about the value.
************************************************************************/

OneWire ds = OneWire(D4);  // 1-wire signal on pin D4

unsigned long lastUpdate = 0;

float lastTemp;
int status0 = D0;
int status1 = D1;

void setup() {
  Serial.begin(9600);
  // Set up 'power' pins, comment out if not used!
  pinMode(status0, OUTPUT);
  pinMode(status1, OUTPUT);
  //digitalWrite(D3, LOW);
  //digitalWrite(D5, HIGH);
  Particle.subscribe("status_eanderson", StatusLight); //subscribe to the fan event
  Particle.subscribe("temperature_carter", templed); //subscribe to the event published by the other sensor
  //flash each LED to show the program has setup
  digitalWrite(status0, HIGH);
  delay(500);
  digitalWrite(status0, LOW);
  delay(500);
   digitalWrite(status1, HIGH);
  delay(500);
  digitalWrite(status1, LOW);
  delay(500);
  
}

// the following portion of the code was taken from the maker kit example "tutorial #4: temperature logger"

// up to here, it is the same as the address acanner
// we need a few more variables for this example

void loop(void) {
  byte i;
  byte present = 0;
  byte type_s;
  byte data[12];
  byte addr[8];
  float celsius, fahrenheit;

  if ( !ds.search(addr)) {
    Serial.println("No more addresses.");
    Serial.println();
    ds.reset_search();
    delay(250);
    return;
  }

  // The order is changed a bit in this example
  // first the returned address is printed

  Serial.print("ROM =");
  for( i = 0; i < 8; i++) {
    Serial.write(' ');
    Serial.print(addr[i], HEX);
  }

  // second the CRC is checked, on fail,
  // print error and just return to try again

  if (OneWire::crc8(addr, 7) != addr[7]) {
      Serial.println("CRC is not valid!");
      return;
  }
  Serial.println();

  // we have a good address at this point
  // what kind of chip do we have?
  // we will set a type_s value for known types or just return

  // the first ROM byte indicates which chip
  switch (addr[0]) {
    case 0x10:
      Serial.println("  Chip = DS1820/DS18S20");
      type_s = 1;
      break;
    case 0x28:
      Serial.println("  Chip = DS18B20");
      type_s = 0;
      break;
    case 0x22:
      Serial.println("  Chip = DS1822");
      type_s = 0;
      break;
    case 0x26:
      Serial.println("  Chip = DS2438");
      type_s = 2;
      break;
    default:
      Serial.println("Unknown device type.");
      return;
  }

  // this device has temp so let's read it

  ds.reset();               // first clear the 1-wire bus
  ds.select(addr);          // now select the device we just found
  // ds.write(0x44, 1);     // tell it to start a conversion, with parasite power on at the end
  ds.write(0x44, 0);        // or start conversion in powered mode (bus finishes low)

  // just wait a second while the conversion takes place
  // different chips have different conversion times, check the specs, 1 sec is worse case + 250ms
  // you could also communicate with other devices if you like but you would need
  // to already know their address to select them.

  delay(1000);     // maybe 750ms is enough, maybe not, wait 1 sec for conversion

  // we might do a ds.depower() (parasite) here, but the reset will take care of it.

  // first make sure current values are in the scratch pad

  present = ds.reset();
  ds.select(addr);
  ds.write(0xB8,0);         // Recall Memory 0
  ds.write(0x00,0);         // Recall Memory 0

  // now read the scratch pad

  present = ds.reset();
  ds.select(addr);
  ds.write(0xBE,0);         // Read Scratchpad
  if (type_s == 2) {
    ds.write(0x00,0);       // The DS2438 needs a page# to read
  }

  // transfer and print the values

  
  Serial.print("  Data = ");
  Serial.print(present, HEX);
  Serial.print(" ");
  

  for ( i = 0; i < 9; i++) {           // we need 9 bytes
    data[i] = ds.read();
    Serial.print(data[i], HEX);
    Serial.print(" ");
  }
  Serial.print(" CRC=");
  Serial.print(OneWire::crc8(data, 8), HEX);
  Serial.println();

  // Convert the data to actual temperature
  // because the result is a 16 bit signed integer, it should
  // be stored to an "int16_t" type, which is always 16 bits
  // even when compiled on a 32 bit processor.
  int16_t raw = (data[1] << 8) | data[0];
  if (type_s == 2) raw = (data[2] << 8) | data[1];
  byte cfg = (data[4] & 0x60);

  switch (type_s) {
    case 1:
      raw = raw << 3; // 9 bit resolution default
      if (data[7] == 0x10) {
        // "count remain" gives full 12 bit resolution
        raw = (raw & 0xFFF0) + 12 - data[6];
      }
      celsius = (int)raw * 0.0625;
      break;
    case 0:
      // at lower res, the low bits are undefined, so let's zero them
      if (cfg == 0x00) raw = raw & ~7;  // 9 bit resolution, 93.75 ms
      if (cfg == 0x20) raw = raw & ~3; // 10 bit res, 187.5 ms
      if (cfg == 0x40) raw = raw & ~1; // 11 bit res, 375 ms
      // default is 12 bit resolution, 750 ms conversion time
      celsius = (int)raw * 0.0625;
      break;

    case 2:
      data[1] = (data[1] >> 3) & 0x1f;
      if (data[2] > 127) {
        celsius = (int)data[2] - ((int)data[1] * .03125);
      }else{
        celsius = (int)data[2] + ((int)data[1] * .03125);
      }
  }

  // remove random errors
  if((((celsius <= 0 && celsius > -1) && lastTemp > 5)) || celsius > 125) {
      celsius = lastTemp;
  }
  
  
  fahrenheit = celsius * 1.8 + 32.0;
  
  lastTemp = celsius;
  Serial.print("  Temperature = ");
  Serial.print(celsius);
  Serial.print(" Celsius, ");
  Serial.print(fahrenheit);
  Serial.println(" Fahrenheit");
  
  
  
  //if(fahrenheit > 75){
  {
  // now that we have the readings, we can publish them to the cloud
  String temperature =  String(fahrenheit); // store temp in "temperature" string
  Particle.publish("temperature_swanger", temperature); // publish to cloud with event name "temperature_swanger"
  delay(10000); // 10 second delay between readings
  }
 

    


}
void StatusLight(const char *event, const char *data) {
   if (strcmp(data,"ON")==0){ //if the fan has been switched on, trigger the green status LED
        digitalWrite(status0,HIGH);
   }
   else if (strcmp(data,"OFF")==0){ //if the fan has been switched off, turn the green status LED off
    digitalWrite(status0,LOW);
        }
    }

void templed(const char *event, const char *data) { //if the other temperature sensor has taken a reading, trigger the white LED
   if (data){ //if the other temperature sensor has taken a reading, trigger the white LED
       digitalWrite(status1,HIGH);
       delay(5000); //illuminate for 5 seconds before turning off
       digitalWrite(status1,LOW);
   }
}

Fan Code

C/C++
This program is intended to read an event published using an IFTTT applet and trigger a servo
that will be mounted on a switch to turn an attic fan on. It will also publish an event when the fan is triggered. One of two LEDs will illuminate whenever a temperature reading is taken. The code can be copied and pasted into the particle web IDE for use.
/*This program is intended to read an event published using an IFTTT applet and trigger a servo
that will be mounted on a switch to turn an attic fan on.
It will also publish an event when the fan is triggered.*/

// This #include statement was automatically added by the Particle IDE.
#include <Adafruit_PWMServoDriver.h>









int boardLed = D7;
int status0 = D0;
int status1 = D1;

Servo myServo; //initialize servo
int pos = 0; //set servo position variable


void setup() {

pinMode(status0, OUTPUT); //set pins as outputs
pinMode(status1, OUTPUT);

pinMode(boardLed,OUTPUT); // Our on-board LED is output as well
myServo.attach(D2);//set servo pin
 myServo.write(15); //set initial servo position
Particle.subscribe("SwangerTemp", TempOut);  //subscribe to the IFTTT event
Particle.subscribe("temperature_swanger", swanger); //subscribe to the temperature readings
Particle.subscribe("temperature_carter", carter);
digitalWrite(boardLed, HIGH); //flash the D7 LED 3 times to show setup has complete
delay(500);
digitalWrite(boardLed, LOW);
delay(500);
digitalWrite(boardLed, HIGH);
delay(500);
digitalWrite(boardLed, LOW);
delay(500);
digitalWrite(boardLed, HIGH);
delay(500);
digitalWrite(boardLed, LOW);
delay(500);
}

void loop(){
   
 
}

void TempOut(const char *event, const char *data) 
{

 
  
  if (strcmp(data,"1")==0) {
    // if the event publishes a value of "1" turn the fan on
    digitalWrite(boardLed,HIGH); //turn the D7 LED on
    Particle.publish("status_eanderson","ON"); //publish an event
    myServo.write(50); //turn the servo to flip the switch
  }
  else if (strcmp(data,"0")==0) {
    // if the event publishes a value of "0" turn the fan off
    digitalWrite(boardLed,LOW); //turn the D7 LED off
    Particle.publish("status_eanderson","OFF"); //publish an event
    myServo.write(15); //turn the servo to flip the switch
  }
}

void swanger(const char *event, const char *data) {
   if (data){ //if a temperature reading is taken trigger the LED
       digitalWrite(status0,HIGH);
       delay(5000); //turn off after five seconds
       digitalWrite(status0,LOW);
   }
}

void carter(const char *event, const char *data) {
   if (data){ //if a temperature reading is taken trigger the LED
       digitalWrite(status1,HIGH);
       delay(5000); //turn off after five seconds
       digitalWrite(status1,LOW);
   }
}

Credits

Eric Anderson

Eric Anderson

1 project • 1 follower
Patrick Swanger

Patrick Swanger

1 project • 0 followers
Carter Daley

Carter Daley

1 project • 0 followers

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