Chopeira Documentation

1. Button class
   
2. Compressor class
   
3. Solenoid class
   
4. Main Code

Button Class

The button class handles the RGB LED indicator.

Constructor

The constructor takes 3 arguments:

1. int r_pin (connected to a digital pin);
2. int g_pin (connected to a digital pin);
3. int b_pin (connected to a digital pin)

Sets the pinMode for each GPIO (3 OUTPUT and on digital INPUT)

e.g:

button power_button(11,10,9)

Methods

set_color(char color)

Void method that changes the color of the RGB button.

Takes a character as argument - the initial of the color the LED should be.

char	color name
R	Red
G	Green
Y	Yellow

void set_color(char color){

            color_name = color;

            switch (color){
                case 'R':


                    analogWrite(red_pin,255);
                    analogWrite(blue_pin,0);
                    analogWrite(green_pin,0);

                    // wait 500 milliseconds,  turn of -> so it will blink until the color changes to green
                    delay(500);

                    analogWrite(red_pin,0);
                    analogWrite(blue_pin,0);
                    analogWrite(green_pin,0);

                    break;

                
                
                case 'G':
                    analogWrite(green_pin,255);
                    analogWrite(blue_pin,0);
                    analogWrite(red_pin,0);
                    break;



                case 'Y':
                    analogWrite(green_pin,50);
                    analogWrite(blue_pin,0);
                    analogWrite(red_pin,255);
                    break;

            }
        }

e.g :

power_button.set_color('R') // Sets the color of the LED to red (and blinks it).

boot_routine()

Void method used to blink the LED in a certain pattern to let the user know the system is booting. It's called in the setUp function in the main file.

void boot_routine(){

            // blink 3 times the led with the green color, to let the user know the boot sequence is starting
            for (int i = 0; i < 3; i++){

                button::set_color('G');
                delay(1000);
                button::turn_led_off();
                delay(1000);
            }
            
    }

---

Compressor Class

The compressor class handles the activation of the relay connected to the compressor/pump from the counter flow cooling system.

Constructor

Takes one argument, the digital pin connected to the Arduino.

It sets the digital pinMode to OUTPUT.

e.g: compressor cooling_system(9) -> Attaches to digital pin 9 on the Arduino Board.

Methods

turn_on_cooling( )

Void method that closes the relay and activate the pump+compressor.

void turn_on_cooling(){

            // Close the relay (so the cooler turns on)
            digitalWrite(pin,HIGH);
        }

e.g: cooling_system.turn_on_cooling();

turn_off_cooling( )

Void method that opens the relay and stops the pump+compressor.

void turn_off_cooling(){

            // Open the relay
            digitalWrite(pin,LOW);
        }

e.g: cooling_system.turn_off_cooling();

---

Solenoid Class

Handles the opening and closing of the release valve for the beer.

Constructor

The constructor takes one argument, the digital output pin on the Arduino.

It sets the pinMode to OUTPUT.

e.g:

solenoid valve(10) // Attaches to pin 10 on the board.

Methods

open_valve( )

Closes the relay that controls the solenoid valve. Which opens the valve and lets liquid through.

void open_valve(){

            // Open the valve so the liquid comes out 
            digitalWrite(pin,HIGH);
        }

e.g:

valve.open_valve(); // opens the valve

close_valve( )

Opens the relay that controls the solenoid valve. Which closes the valve and holds the liquid.

void close_valve(){

            // Close the valve 
            digitalWrite(pin,LOW);
        }

e.g:

valve.close_valve(); // closes the valve

---

Main Code

Include the necessary libraries(" "are for files in the local directory and < > are for files in the default directory):

#include "compressor.h"
#include "solenoid.h"
#include "button.h"

#include <OneWire.h>
#include <DallasTemperature.h>

Setup the temperature sensor library:

// Data wire is connected to the Arduino digital pin 4
#define ONE_WIRE_BUS 12

// Setup a oneWire instance to communicate with any OneWire devices
OneWire oneWire(ONE_WIRE_BUS);

// Pass our oneWire reference to Dallas Temperature sensor 
DallasTemperature sensors(&oneWire);

Instantiate the custom classes:

// instantiate compressor to control cooling system and attach it to GPIO 9 / instantiate the selonoide class and attach it to pin 10 on the arduino  / instance the button class and Set the data pin to 13, red led to analof A0, green to analog A1, blue to analog A2
compressor cooling_system(7);
solenoid  valve(8);
button power_button(11,10,9);

Set the target temperature:

// Set the target temperature for the liquid
const float min_target_temperature PROGMEM = 0.0f;
const float max_target_temperature PROGMEM = 2.0f;

obs: Set them to const so they don't change through the code, and set them to PROGMEM, so they are not stored in SRAM and don't take dynamic memory space.

Creates a boolean variable to track rather or not it's the first iteration for the machine

bool first_iteration = true;

Start the sensors and close the valves (prevent liquid waste):

void setup(){
    
    // Start the emperature sensor 
    sensors.begin();

    // close the vaulve to avoid leaking
    valve.close_valve();

    // Set the LED color to RED
    power_button.set_color('R');

    // Start the boot sequence for the LED, to let the user know that it's starting
    power_button.boot_routine();
}

Inside the loop function

Get the temperature from the sensor:

// Resquest the temperature for all the sensors connected to the arduino 
sensors.requestTemperatures(); 

// Check the temperature  - by index means it's getting the data for the first sensor (if in the future more sensores are added) -- index starts at 0
float current_temperature = sensors.getTempCByIndex(0);

If the temperature is above target, turn on cooling, if it is the first iteration of the machine it means that the solenoid valve will be closed, so set the RGB color to red. If it is nor the first iteration, even though the temperature is outside the threshold the valve will not close, so set the RGB to yellow so the user knows it's still possible to get the beer, but it will not be in the right temperature and that the user should wait.

// If the temperature is higher than the target, turn on the cooling system
    if (current_temperature > max_target_temperature){
        
        // turn on the cooling system
        cooling_system.turn_on_cooling();

        // If it's the first iteration, turn the LED red so the user knows the machine won't release beer 
        if (first_iteration){

            // Turn the LED to red 
            power_button.set_color('R');
        }

        // If it's not the first iteration, the solenoid will continue to be open, but set the color to yellow so the user knows the beer is not within the temperature threshold
        else if (!first_iteration){
            
            // Set the color to yellow
            power_button.set_color('Y');
        }
        
    }

If the temperature is equal or bellow the target, turn off the cooling and set the RGB color to solid green:

// If the temperature is lower than the target, turn off the cooling system
    else if (current_temperature <= min_target_temperature){

        // turn off the cooling system 
        cooling_system.turn_off_cooling();

    }

If the temperature is within the threshold, open the valve (and leave it open) and let the liquid flow, and set the RGB color to Green, so the user knows the machine is operating:

else if (current_temperature <= max_target_temperature)
    {
        // Set the first iteration variable to false, since the timeperature already reached the threshold at least for the first time
        first_iteration = false;

        // open the valve 
        valve.open_valve();

        // Set the button color to green, so the user knows the valve is open
        power_button.set_color('G');

    }

Wait the necessary time for the temperature sensor to update its readings

// wait for one second before next iteration (1000 ms) ----- time between measurements for the temperature sensor 
    delay(1000);