Tutorial arduino fan speed controlled by temp

http://www.electroschematics.com/9540/arduino-fan-speed-controlled-temperature/

going to try this looks interesting for fancying up a control box. gonna use it for north bridge cooler on top of moto vnh chips. ill use nano also for this. pics to follow.

ok ive compiled a parts list. now just wait for stuff in the mail.

fan speed controller parts list

1n4007 rectifier x 1
bd139 transistor x 1
100uf/16v capacitor x 1
1k resistor x 2 v
red led x 1 v
16x2 lcd x 1 v
lm35 temp sensor x 1 v
photo resistor x 1 v
12v fan 40mm x 2 v
arduino x 1 v
proto/bread board x 1 v

EDIT:THIS CODE DOES NOT COMPILE I HAVE POSTED A SIMPLER VERSION BELOW


This is the code i intend to use.

krowvin on March 10, 2015 at 3:48 am
reply
I modified your code to do a few things. I haven’t got to test it with the hardware yet (waiting on it to be delivered), but it seems to compile. Here’s my code if anyone would like to take a look.

Added LDR (photo resistor to control LCD back light)
Added a second fan (fans should function at the same speed)
Add scenarios for when temp is below and above threshold
(below fans turn off, above fans go to max)
Also added code to show LCD as 0% or 100% Author has the line
fanSpeed = 0; but I think he meant to use fanlcd = 0;

#include <LiquidCrystal.h>
//original: http://www.electroschematics.com/9540/arduino-fan-speed-controlled-temperature/
LiquidCrystal lcd(7,6,5,4,3,2);
int tempPin = A1; // the output pin of LM35
int photoPin = A0; //photoresistor for LCD backlight
int fan1 = 11; // the pin where fan is
int fan2 = 10;
int lcdbl = 9; // LCD backlight pin (connect to pin +15 on LCD
// (NOTE: pin 16 is -)
int led = 8; // led pin for HIGH temp warning
int temp;
int tempMin = 27; // 27C = 80.6F the temperature to start the fan
int tempMax = 40; // 40C = 104F the maximum temperature when fan is at 100%
int ldr = -1; //0..1023
int fanSpeed;
int fanLCD;

void setup() { //set pins as input or outputs
pinMode(fan1, OUTPUT);
pinMode(fan2, OUTPUT);
pinMode(led, OUTPUT);
pinMode(lcdbl, OUTPUT);
pinMode(tempPin, INPUT);
lcd.begin(16,2);
}

void loop() {
temp = readTemp(); // get the temperature
if(temp = tempMin) && (temp tempMax) { // if temp is higher than max temp
digitalWrite(led, HIGH); // turn on led
digitalWrite(fan1, HIGH); //set fans to max
digitalWrite(fan2, HIGH);
fanLCD = 100; //Shows 100% use on LCD for fan
} else { // else turn off led
digitalWrite(led, LOW);
}

ldr=analogRead(photoPin);
if(ldr<=511) { //if ldr is <= 511 turn backlight on
digitalWrite(lcdbl, HIGH);
} else {
digitalWrite(lcdbl, LOW); //if greater, turn LCD BL off
}
lcd.print("TEMP: ");
lcd.print(temp); // display the temperature
lcd.print("C ");
lcd.setCursor(0,1); // move cursor to next line
lcd.print("FANS: ");
lcd.print(fanLCD); // display the fan speed
lcd.print("%");
delay(200); //give time to read text before changing
lcd.clear();
}

int readTemp() { // get the temperature and convert it to celsius
temp = analogRead(tempPin);
return temp * 0.48828125;
}


+++++++++NEW CODE+++++++++++

#include<LiquidCrystal.h>
//source: http://www.electroschematics.com/9540/arduino-fan-speed-controlled-temperature/
LiquidCrystal lcd(7,6,5,4,3,2);
int tempPin = A1;// the output pin of LM35
int fan =11;// the pin where fan is
int led =8;// led pin
int temp;
int tempMin =30;// the temperature to start the fan
int tempMax =70;// the maximum temperature when fan is at 100%
int fanSpeed;
int fanLCD;
void setup(){
pinMode(fan, OUTPUT);
pinMode(led, OUTPUT);
pinMode(tempPin, INPUT);
lcd.begin(16,2);
}
void loop(){
temp = readTemp();// get the temperature
if(temp < tempMin){// if temp is lower than minimum temp
fanSpeed =0;// fan is not spinning
digitalWrite(fan, LOW);
}
if((temp >= tempMin)&&(temp <= tempMax)){// if temperature is higher than minimum temp
fanSpeed = map(temp, tempMin, tempMax,32,255);// the actual speed of fan
fanLCD = map(temp, tempMin, tempMax,0,100);// speed of fan to display on LCD
analogWrite(fan, fanSpeed);// spin the fan at the fanSpeed speed
}
if(temp > tempMax){// if temp is higher than tempMax
digitalWrite(led, HIGH);// turn on led
}else{// else turn of led
digitalWrite(led, LOW);
}
lcd.print("TEMP: ");
lcd.print(temp);// display the temperature
lcd.print("C ");
lcd.setCursor(0,1);// move cursor to next line
lcd.print("FANS: ");
lcd.print(fanLCD);// display the fan speed
lcd.print("%");
delay(200);
lcd.clear();
}
int readTemp(){// get the temperature and convert it to celsius
temp = analogRead(tempPin);
return temp *0.48828125;
}​

interesting !! Thank you

Looks interesting. Thanks for sharing, maybe I can include this in my Diy Led Lamp.