Mudanças entre as edições de "Incubadora de Placas de Petri"

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[[Arquivo:Incubadora_Esquema_Eletrônico.jpg|300px]]
  
[[Arquivo:Incubadora_Esquema_Eletrônico.jpg|300px]]
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O código Arduino escrito:
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<code>
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#include <LiquidCrystal.h>
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#include <math.h>
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//Variables//
  +
  +
//Electronic system configuration
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int thermistorPin = A0; // Pin where the thermistor is connected
  +
int minusButton = 9; // Pin where the menu temperature decreasing button is connected
  +
int plusButton = 10; // Pin where the menu temperature increasing button is connected
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int fanRelay = 11; // Pin where the Relay Module for controlling the fans is connected
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int lampRelay = 12; // // Pin where the Relay Module for controlling the heating lamp is connected
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LiquidCrystal lcd(2, 3, 5, 6, 7, 8);
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//Operational variables
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int standardTemp = 25; // Initial temperature of the Incubator
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int maxTemp = 45; // for safety precautions, 45 celsius is the largest value the incubator may have
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int minTemp = 20; // temperature arbitrary defined for the minimum temperature setting allowed
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int maxHeat = 2; // maximum temperature difference allowed for the current temperature to be higher than the defined by the user
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int refreshingRate = 500; // Milliseconds that each loop waits for checking the temp and if the buttons are pressed
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//Temperature equation constants
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double Beta = 3435; // Beta value (or "B" value) from the thermistor, using the Beta parameter equation, a particular case of the Steinhart–Hart equation for thermistors
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double R25 = 10000; // Resistance of the thermistor at 25 celsius
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double Ref = 10000; // Resistance of Reference from the Voltage Divider Circuit (10K for example)
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//Functions//
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void CheckButtons(int plus, int minus){ // Checks if the user press-and-holded one of the two buttons and changes the standardTemp variable. Also refresh the LCD screen for the target temperature
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while(digitalRead(plus) == HIGH){ //while the user is pressing the button the target temperature is incremented
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if(standardTemp == maxTemp){ // if the standardTemp reaches the maximum temperature allowed it is not incremented anymore
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break;
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}
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standardTemp++;
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lcd.setCursor(9, 0);
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lcd.print(standardTemp, DEC);
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delay(300); // this defines how fast the numbers being set on the LCD screen are changed
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}
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while(digitalRead(minus) == HIGH){ //while the user is pressing the button the target temperature is decremented
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if(standardTemp == minTemp){ // if the standardTemp reaches the minimum temperature allowed it is not decremented anymore
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break;
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}
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standardTemp--;
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lcd.setCursor(9, 0);
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lcd.print(standardTemp, DEC);
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delay(300); // this defines how fast the numbers being set on the LCD screen are changed
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}
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}
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double MeasureResistance(int ARead){ // Transforms pwm values of thermistorPin in voltage and calculates the thermistor resistance by the voltage divider equation
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double Rtherm = ((5.0*Ref)/(ARead*(5.0/1023.0))) - Ref;
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return Rtherm;
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}
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int CalculateTemp(double resistance){ //Given the resistance value of the thermistor, returns the temperature by using the thermistor equation for termperature
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double T = ((298.0*Beta)/(298.0*log(resistance/R25) + Beta)); // Beta parameter equation, a particular case of the Steinhart–Hart equation for thermistors. Temperature of reference is 25 Celsius.
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T = T-273; // converts Kelvin to Celsius
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return T;
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}
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byte degree[8] = { //Generates the "degree" character of the Celsius representation on the LCD screen
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B00111,
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B00101,
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B00111,
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B00000,
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B00000,
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B00000,
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B00000,
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};
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void setup() {
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// LCD stetup //
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lcd.begin(16, 2);
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lcd.setCursor(0, 0);
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lcd.print("Target:");
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lcd.setCursor(11, 0);
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lcd.write(byte(degree[8]));
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lcd.print("C");
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lcd.setCursor(0, 1);
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lcd.print("Status:");
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lcd.setCursor(11, 1);
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lcd.write(byte(degree[8]));
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lcd.print("C");
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// Pins Setup //
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pinMode(plusButton, INPUT);
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pinMode(minusButton, INPUT);
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pinMode(fanRelay, OUTPUT);
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pinMode(lampRelay, OUTPUT);
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}
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void loop() {
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//Data gathering//
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CheckButtons(plusButton, minusButton); //Checks for new user inputs
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double Rvalue = MeasureResistance(analogRead(thermistorPin)); // The Voltage measured on thermistorPin is converted to Resistance by measureResistance and the temperature is given by calculateTemp, then the LCD is refreshed
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int Temp = CalculateTemp(Rvalue); // Returns, in Celsius, the current temperature value;
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lcd.setCursor(9, 1);
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lcd.print(Temp, DEC); //LCD current temperature refreshing
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//Incubator Controlling//
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if(Temp < standardTemp){ // if the current temp is lower than the target, it turns on the lamp
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digitalWrite(lampRelay, HIGH);
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if(digitalRead(fanRelay) == HIGH){ // in case the cooling fans were on, they're shut down
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digitalWrite(fanRelay, LOW);
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}
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}
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if(Temp > standardTemp){ // if the current temp is higher than the target, it turns off the lamp
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digitalWrite(lampRelay, LOW);
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if(Temp >= standardTemp + maxHeat){ // in case the current temperature is too high (defined by maxHeat), the cooling fans are turned on
  +
digitalWrite(fanRelay, HIGH);
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}
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}
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if(Temp == standardTemp && digitalRead(lampRelay) == HIGH){ // in case the current temperature matches the one defined by the user and the lamp is on, it turns it off
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digitalWrite(lampRelay, LOW);
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}
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if(Temp == standardTemp && digitalRead(fanRelay) == HIGH){ // in case the current temperature matches the one defined by the user and the fans are on, it turns them off
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digitalWrite(fanRelay, LOW);
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}
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delay(refreshingRate); //time the microcontroller stays idle until the next check and controlling cycle
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}
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</code>
   
 
==Referências==
  
==Referências==

Edição das 23h06min de 10 de agosto de 2015

Incubadora.jpg

Objetivo

O objetivo desse projeto é criar uma incubadora para cultivo de microorganismos em placas de petri. Com esse equipamento é possível garantir o crescimento nas melhores condições controladas para diferentes tipos de microrganismos. Uma incubadora é um dos equipamentos essenciais para qualquer laboratório de microbilogia ou biologia molecular.

Design

O design da incubadora foi feito para uma estrutura de mdf de 3mm de espessura com encaixes para parafusos de máquina de 10 mm de comprimento e 3,4 mm de diâmetro. O design é baseado no projeto "Incubator" da Biohack Academy e as partes em mdf foram cortadas no Garagem FAB Lab. Uma mudança da funcionalidade do design original foi a colocação de coolers para resfriamento do interior da incubadora caso necessário.

Modelo 3D

O modelo 3D da incubadora foi feito em sketchup. O modelo e sua planificação estão disponíveis para download aqui:

Debugando o Hardware

Após cortar na laser percebeu-se que as medidas cortadas foram cerca de 10% maiores do que o esperado. O plano era aproveitar uma caixa de isopor para ser o isolante. Por causa disso foi preciso arrumar placas avulsas de isopor de espessura adequada, o que deu um pouco mais de trabalho. É importante tomar cuidado com as importações para dxf à partir do sketchup. Usamos esse plugin.

  • Cobrimos a parte interna com papel alumínimo.

  • Ficou grande demais!

  • Montando a parte externa.

A dobradiça em mdf é bonitinha mas quebra com facilidade. É melhor usar uma dobradiça comercial facilmente encontrável por aí - aproveite e compre uma tranca simples também.

  • Dobradiça facilmente quebrável.

  • Tranca comum.

Eletrônica e Elétrica

Usamos um dos clones brasileiros do Arduino mais mão-na-roda do mercado, o Garagino rev1, montando todo o circuito em protoboard. O controle todo é muito simples: um relê controlando o par de coolers de resfriamento, um relê controlando o liga-e-desliga da lâmpada incandescente (que é fonte de aquecimento), um termistor (foi usado um termistor bem não-convencional por questões de disponibilidade, esse aqui) medindo a temperatura, dois botões e um LCD.

O esqueminha eletrônico construído foi o seguinte:

Incubadora Esquema Eletrônico.jpg

O código Arduino escrito:

  1. include <LiquidCrystal.h>
  2. include <math.h>
 //Variables//

//Electronic system configuration int thermistorPin = A0; // Pin where the thermistor is connected int minusButton = 9; // Pin where the menu temperature decreasing button is connected int plusButton = 10; // Pin where the menu temperature increasing button is connected int fanRelay = 11; // Pin where the Relay Module for controlling the fans is connected int lampRelay = 12; // // Pin where the Relay Module for controlling the heating lamp is connected LiquidCrystal lcd(2, 3, 5, 6, 7, 8);

//Operational variables int standardTemp = 25; // Initial temperature of the Incubator int maxTemp = 45; // for safety precautions, 45 celsius is the largest value the incubator may have int minTemp = 20; // temperature arbitrary defined for the minimum temperature setting allowed int maxHeat = 2; // maximum temperature difference allowed for the current temperature to be higher than the defined by the user int refreshingRate = 500; // Milliseconds that each loop waits for checking the temp and if the buttons are pressed

//Temperature equation constants double Beta = 3435; // Beta value (or "B" value) from the thermistor, using the Beta parameter equation, a particular case of the Steinhart–Hart equation for thermistors double R25 = 10000; // Resistance of the thermistor at 25 celsius double Ref = 10000; // Resistance of Reference from the Voltage Divider Circuit (10K for example) 

 //Functions//

void CheckButtons(int plus, int minus){ // Checks if the user press-and-holded one of the two buttons and changes the standardTemp variable. Also refresh the LCD screen for the target temperature 

 while(digitalRead(plus) == HIGH){ //while the user is pressing the button the target temperature is incremented
   if(standardTemp == maxTemp){ // if the standardTemp reaches the maximum temperature allowed it is not incremented anymore
     break;
   }
   standardTemp++;
   lcd.setCursor(9, 0);
   lcd.print(standardTemp, DEC); 
   delay(300); // this defines how fast the numbers being set on the LCD screen are changed
 }
 while(digitalRead(minus) == HIGH){ //while the user is pressing the button the target temperature is decremented
   if(standardTemp == minTemp){ // if the standardTemp reaches the minimum temperature allowed it is not decremented anymore
     break;
   }
   standardTemp--;
   lcd.setCursor(9, 0);
   lcd.print(standardTemp, DEC);
   delay(300);  // this defines how fast the numbers being set on the LCD screen are changed
 }

}

double MeasureResistance(int ARead){ // Transforms pwm values of thermistorPin in voltage and calculates the thermistor resistance by the voltage divider equation 

 double Rtherm = ((5.0*Ref)/(ARead*(5.0/1023.0))) - Ref;
 return Rtherm;

}

int CalculateTemp(double resistance){ //Given the resistance value of the thermistor, returns the temperature by using the thermistor equation for termperature 

 double T = ((298.0*Beta)/(298.0*log(resistance/R25) + Beta)); // Beta parameter equation, a particular case of the Steinhart–Hart equation for thermistors. Temperature of reference is 25 Celsius.
 T = T-273; // converts Kelvin to Celsius
 return T;

}

byte degree[8] = { //Generates the "degree" character of the Celsius representation on the LCD screen 

 B00111,
 B00101,
 B00111,
 B00000,
 B00000,
 B00000,
 B00000,

};

void setup() { 

 // LCD stetup //
 lcd.begin(16, 2);
 lcd.setCursor(0, 0);
 lcd.print("Target:");
 lcd.setCursor(11, 0);
 lcd.write(byte(degree[8]));
 lcd.print("C"); 
 lcd.setCursor(0, 1);
 lcd.print("Status:");
 lcd.setCursor(11, 1);
 lcd.write(byte(degree[8]));
 lcd.print("C");
 
 // Pins Setup //
 
 pinMode(plusButton, INPUT);
 pinMode(minusButton, INPUT);
 
 pinMode(fanRelay, OUTPUT);
 pinMode(lampRelay, OUTPUT);

}

void loop() { 

 //Data gathering//
 
 CheckButtons(plusButton, minusButton); //Checks for new user inputs
 double Rvalue = MeasureResistance(analogRead(thermistorPin)); // The Voltage measured on thermistorPin is converted to Resistance by measureResistance and the temperature is given by calculateTemp, then the LCD is refreshed
 int Temp = CalculateTemp(Rvalue); // Returns, in Celsius, the current temperature value;
 lcd.setCursor(9, 1);
 lcd.print(Temp, DEC); //LCD current temperature refreshing

  //Incubator Controlling//

 if(Temp < standardTemp){ // if the current temp is lower than the target, it turns on the lamp
   digitalWrite(lampRelay, HIGH);
   if(digitalRead(fanRelay) == HIGH){ // in case the cooling fans were on, they're shut down
     digitalWrite(fanRelay, LOW);
   }
 }
 if(Temp > standardTemp){ // if the current temp is higher than the target, it turns off the lamp
   digitalWrite(lampRelay, LOW);
   if(Temp >= standardTemp + maxHeat){ // in case the current temperature is too high (defined by maxHeat), the cooling fans are turned on
     digitalWrite(fanRelay, HIGH);
   }
 }
 if(Temp == standardTemp && digitalRead(lampRelay) == HIGH){  // in case the current temperature matches the one defined by the user and the lamp is on, it turns it off
   digitalWrite(lampRelay, LOW);
 }
 if(Temp == standardTemp && digitalRead(fanRelay) == HIGH){  // in case the current temperature matches the one defined by the user and the fans are on, it turns them off
   digitalWrite(fanRelay, LOW);
 }
 
 delay(refreshingRate); //time the microcontroller stays idle until the next check and controlling cycle

}

Referências

Disponível em “https://garoa.net.br/mediawiki/index.php?title=Incubadora_de_Placas_de_Petri&oldid=19613”