Jacob's Workshop: Using an ATTiny85 to control a relay based on an LM34 temperature reading

The following code uses an ATTiny85 to turn a relay on and off based on a temperature reading from the LM34 temperature sensor. I used this to turn a freezer on and off to help save energy and to prevent the freezer from actually freezing anything.

/*
 * LM34.c
 *
 * Created: 4/13/2015 10:35:05 PM
 *  Author: Jacob
 */


#include <avr/io.h>
#include <util/delay.h>

#define relay PB1 //The relay is connected to PB1 on the ATTiny85
#define led PB0 //The indicator LED is connect to PB0 on the ATTiny85

void ledAlert() //Function used to blink the LED at a fast pulse, used for alerting user if there is an error with the cooling system
{
 PORTB ^= (1 << led); //Toggle the LED
 _delay_ms(250); //LED state changes every 250 milliseconds
}

void initADC() {
 
 DDRB |= (1 << relay); //Sets the relay pin as an output
 DDRB |= (1 << led); //Sets the led pin as an output
 
 ADCSRA |= (1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0);
 //Setting a 1 to "ADEN" enables the ADC feature
 //Setting a 1 to "ADPS2, ADPS1, ADPS0" sets the pre-scaler to divide the clock by 128
 ADMUX |= (0<<REFS0)|(0<<REFS1); //Reference = Vcc
 ADMUX |= (1<<ADLAR); //Left adjust ADC results
 ADMUX |= (1<<MUX1); //Select ADC3 (pin 2)
 ADMUX |= (1<<MUX0); //Select ADC3 (pin 2)
 ADCSRA |= (1 << ADATE); //Free running mode
 ADCSRB &= ~((1<<ADTS2)|(1<<ADTS1)|(1<<ADTS0)); //First three bits of ADCSRB needs to be 000 to select free running mode
 ADCSRA |= (1<<ADEN); //Completes the initialization of ADC
 ADCSRA |= (1<<ADSC); //Start ADC conversions
  
}

int main(void)
{
 initADC(); //Initialize the registers so the ATTiny85 can perform Analog to Digital Conversions
    while(1)
 {
  if(ADCH > 19) //(19/255) * 5 = 39.2 degrees //If the temperature is above 39 degrees, Turn the relay and led on
  {
   PORTB |= (1 << relay);
   PORTB |= (1 << led);
   while(ADCH > 18); //35.3 //While the temperature is greater than 35 degrees, stay here to temporarily lock it in place
  }
  else //If the temperature is below 39 degrees, turn the relay off so the beer doesn't freeze
  {
   PORTB &= (0 << relay); //Turn relay off if the temperature is acceptable (below 38 degrees)
   PORTB &= (0 << led); //Turn led off if the temperature is acceptable (below 38 degrees)
  }
    }
}
 
/*
8 bit value to degrees F
15 -> 29.4
16 -> 31.3
17 -> 33.3
18 -> 35.3
19 -> 37.2
20 -> 39.2
21 -> 41.1
22 -> 43.1
23 -> 45.1
*/

I don't have a wiring diagram or pictures to show as I no longer need this project. But this is a good example to show how to read an analog input into the ATTiny85 using the ADC.

2 comments:

rabpadinNovember 7, 2022 at 12:52 AM
Learning a brand new} sport and picking up the entire guidelines and techniques may be challenging and perhaps even a bit boring, however a wager will keep you engaged and give you more of a reason to stick with the game. For instance, find a way to|you possibly can} wager on the NFL player that can secure essentially the most passing yards, speeding yards or receiving yards through the season. If you wager on the 49ers to cowl, they need to|they should} win by 7 or more points. A wager on the Bears to cowl would pay out in the event that they} received 파라오카지노 도메인 the game or lost by as much as} 6 points.
parksackettNovember 8, 2022 at 7:27 PM
As the ball begins to slow down, the dealer waves an arm over the desk, indicating no extra bets. At this point, gamers usually are not allowed to add or take away something from the desk. Once the ball 배당 토토 involves a cease, the dealer marks the quantity with the dolly and proclaims the quantity rolled, colour and odd and even.

Monday, December 14, 2015

Using an ATTiny85 to control a relay based on an LM34 temperature reading

2 comments: