Lekcia 47: Použitie K-typu MAX6675 ako termostatu s relé | Kurz Arduino Krok za krokom
Tento projekt vás prevedie stavbou systému regulácie teploty pomocou Arduina, termočlánku K-type MAX6675 a relé. Tento systém dokáže udržiavať požadovaný rozsah teplôt, vďaka čomu je vhodný na rôzne aplikácie. Môžete ho použiť na stavbu:
- Inkubátora s reguláciou teploty pre citlivé experimenty alebo priesady.
- Automatizovaného varného systému na udržiavanie konzistentnej teploty mladiny.
- Klimatizovaného priestoru pre plazy alebo iné teplocitlivé zvieratá.
- Jednoduchého vykurovacieho alebo chladiaceho systému pre malý priestor.
-
robojax_course_47_MAX6675_temperature-0
Systém používa MAX6675 na čítanie teplôt z termočlánku K-type, čo poskytuje presné merania teploty v širokom rozsahu (v závislosti od typu termočlánku až do 1000°C alebo viac). Arduino spracúva tieto hodnoty a ovláda relé na zapínanie alebo vypínanie vykurovacieho alebo chladiaceho prvku, čím udržiava teplotu v rámci používateľom definovaného rozsahu. (vo videu o 00:32)
Hardvér/Komponenty
Na stavbu tohto projektu budete potrebovať nasledujúce komponenty:
- Doska Arduino (Uno, Nano atď.)
- Zosilňovač termočlánku MAX6675
- Termočlánok K-type
- Reléový modul
- AC žiarovka (alebo iná záťaž, napríklad ventilátor alebo ohrievač)
- Prepojovacie vodiče
- Nepájivé pole (voliteľné, ale odporúčané)
Sprievodca zapojením
Zapojenie je podrobne vysvetlené vo videu. (vo videu o 03:28) Pozrite si video pre vizuálny návod. Kľúčové pripojenia zahŕňajú pripojenie MAX6675 k Arduinu (piny 2-6), reléového modulu k Arduinu (pin 8 a napájanie) a reléového modulu k AC záťaži. Kritickým aspektom je správna identifikácia fázového a nulového vodiča vašej AC záťaže pred ich pripojením k relé. Nesprávne zapojenie môže viesť k nebezpečným situáciám.
Vysvetlenie kódu
Kód Arduina (zobrazený v úryvkoch nižšie) využíva knižnicu MAX6675 na čítanie hodnôt teploty z termočlánku. Používateľsky konfigurovateľné časti kódu sú:
relayPin: Pin Arduina pripojený k reléovému modulu (predvolené: 8). (vo videu o 07:35)relayONarelayOFF: Tieto konštanty definujú logické úrovne na zapnutie a vypnutie relé. Zvyčajne sú to LOW a HIGH, ale môže byť potrebné ich upraviť v závislosti od vášho reléového modulu. (vo videu o 07:35)TEMPERATURE_UNIT: Nastavuje jednotku pre meranie teploty (1 pre Celzia, 2 pre Fahrenheita, 3 pre Kelvina). (vo videu o 08:21)START_TEMPERATUREaSTOP_TEMPERATURE: Tieto premenné definujú rozsah teplôt pre riadiaci systém. Systém zapne relé, keď teplota klesne podSTART_TEMPERATURE, a vypne ho, keď teplota dosiahneSTOP_TEMPERATURE(alebo naopak, v závislosti od toho, či ovládate ohrievač alebo chladič). (vo videu o 08:31)CONTROL_TYPE: Premenná, ktorá určuje, či systém funguje ako ohrievač (1) alebo chladič (2). (vo videu o 08:36)
Kód obsahuje funkcie ako readTemperature(), printTemperature(), loadControl() a relayControl() na spracovanie čítania teploty, zobrazenia a činnosti relé. Tieto funkcie sú jasne definované a vysvetlené vo videu. (vo videu o 09:37, 10:00, 10:43, 11:30)
const int relayPin =8;
const int relayON = LOW;// do not change
const int relayOFF = HIGH; //do not change
int relayState = relayOFF;//initial state of relay
const int TEMPERATURE_UNIT =1;//1=Celsius, 2=Fahrenheit, 3=Kelvin
const float START_TEMPERATURE = 80.0;//unit above
const float STOP_TEMPERATURE = 100.0;//unit above
const int CONTROL_TYPE = 1;// 1= heater, 2=cooler
Živý projekt/Demonštrácia
Video demonštruje fungovanie systému regulácie teploty pre scenáre vykurovania aj chladenia. (vo videu o 13:15 a 15:28) Demonštrácia jasne ukazuje, ako systém udržiava teplotu v nastavenom rozsahu zapínaním a vypínaním relé podľa potreby.
Kapitoly
- [00:00] Úvod
- [00:55] Vysvetlenie ovládania ohrievača/chladiča
- [03:28] Schéma zapojenia
- [06:26] Vysvetlenie kódu
- [13:15] Demonštrácia ovládania ohrievača
- [15:28] Demonštrácia ovládania chladiča
- [17:29] Záver
/*
* This is the Arduino code for MAX6675 Thermocouple K-Type with Relay and Display
* The output pin 10 is connected to the relay.
* When the temperature reaches the desired value, pin 10 turns the
* relay ON.
* This code has been explained in our video at https://youtu.be/cD5oOu4N_AE
*
* Written by Ahmad Nejrabi for Robojax Video
* Date: December 9, 2017, in Ajax, Ontario, Canada
* Permission granted to share this code given that this
* note is kept with the code.
* Disclaimer: This code is "AS IS" and for educational purposes only.
*
*/
// This example is public domain. Enjoy!
// www.ladyada.net/learn/sensors/thermocouple
#include "max6675.h"
int thermoDO = 4;
int thermoCS = 5;
int thermoCLK = 6;
MAX6675 thermocouple(thermoCLK, thermoCS, thermoDO);
int vccPin = 3;
int gndPin = 2;
void setup() {
Serial.begin(9600);
// Use Arduino pins
pinMode(vccPin, OUTPUT); digitalWrite(vccPin, HIGH);
pinMode(gndPin, OUTPUT); digitalWrite(gndPin, LOW);
pinMode(10, OUTPUT);// set pin 10 as output
Serial.println("Robojax: MAX6675 test");
// wait for MAX chip to stabilize
delay(500);
}
void loop() {
// basic readout test, just print the current temp
Serial.print("C = ");
Serial.println(thermocouple.readCelsius());
Serial.print("F = ");
Serial.println(thermocouple.readFahrenheit());
// If temperature goes above 80.0C, turn the relay ON
if(thermocouple.readCelsius() > 80.00){
digitalWrite(10, LOW);// set pin 10 LOW
}else{
digitalWrite(10, HIGH);// set pin 10 HIGH
}
delay(1000);
}
++
/*
* Library from: // www.ladyada.net/learn/sensors/thermocouple
*
* This is Arduino code to measure MAX6675 Thermocouple K-Type sensor
* and control relay as heater or cooler
*
* Watch Video instruction for this code: https://youtu.be/dVh77wT-4Ao
*
* Written by Ahmad Shamshiri on May 20, 2020 in Ajax, Ontario, Canada
* www.robojax.com
*
* Get this code and other Arduino codes from Robojax.com.
Learn Arduino step by step in a structured course with all material, wiring diagrams, and libraries
all in one place. Purchase My course on Udemy.com http://robojax.com/L/?id=62
If you found this tutorial helpful, please support me so I can continue creating
content like this.
or make a donation using PayPal http://robojax.com/L/?id=64
Related videos:
Introduction to MAX6675 K-Type: https://youtu.be/VGqONmUinqA
Using MAX6675 K-Type thermocouple with LED display: https://youtu.be/cD5oOu4N_AE
Using MAX6675 K-Type thermocouple with LCD1602-I2C: https://youtu.be/BlhpktgPdKs
Using 2 or more MAX6675 K-Type thermocouples: https://youtu.be/c90NszbNG8c
Using MAX6675 K-Type thermocouple as heater or cooler controller: [this video]
* * This code is "AS IS" without warranty or liability. Free to be used as long as you keep this note intact.*
* This code has been downloaded from Robojax.com
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include "max6675.h"
//Robojax.com heater/cooler with MAX6675 Thermocoupler
int GNDpin = 2;
int VCCpin =3;
int thermoCLK = 4;
int thermoCS = 5;
int thermoDO = 6;
MAX6675 thermocouple(thermoCLK, thermoCS, thermoDO);
const int relayPin =8;
const int relayON = LOW;// do not change
const int relayOFF = HIGH; //do not change
int relayState = relayOFF;//initial state of relay
const int TEMPERATURE_UNIT =1;//1=Celsius, 2=Fahrenheit, 3=Kelvin
const float START_TEMPERATURE = 80.0;//unit above
const float STOP_TEMPERATURE = 100.0;//unit above
const int CONTROL_TYPE = 1;// 1= heater, 2=cooler
float temperature;
void setup() {
//Robojax.com heater/cooler with MAX6675 Thermocoupler
Serial.begin(9600);
Serial.println("MAX6675 test with relay");
// use Arduino pins
pinMode(relayPin, OUTPUT);//pin for relay
digitalWrite(relayPin, relayState);
pinMode(VCCpin, OUTPUT);
digitalWrite(VCCpin, HIGH);
pinMode(GNDpin, OUTPUT);
digitalWrite(GNDpin, LOW);
// wait for MAX chip to stabilize
delay(500);
//Robojax.com heater/cooler with MAX6675 Thermocoupler
}
void loop() {
//Robojax.com heater/cooler with MAX6675 Thermocoupler
readTemperature();
printTemperature();
loadControl();
if(temperature >=89.5)
{
///
}
delay(1000);
//Robojax.com heater/cooler with MAX6675 Thermocoupler
}//loop
/*
* loadControl()
* @brief controls the load based
* @param state can be either : relayON or relayOFF
* @return returns none
* Written by Ahmad Shamshiri for robojax.com
* on May 20, 2020 at 15:23 in Ajax, Ontario, Canada
*/
void loadControl()
{
//Robojax.com heater/cooler with MAX6675 Thermocoupler
// Serial.print("Start: ");
// Serial.print(START_TEMPERATURE);
// Serial.print(" Stop: ");
//Serial.println(STOP_TEMPERATURE);
if(CONTROL_TYPE ==1)
{
if(START_TEMPERATURE >= temperature && STOP_TEMPERATURE >=temperature)
{
relayControl(relayON);
}
if(STOP_TEMPERATURE <=temperature)
{
relayControl(relayOFF);
}
}else{
if(START_TEMPERATURE >= temperature && STOP_TEMPERATURE >=temperature)
{
relayControl(relayOFF);
}
if(STOP_TEMPERATURE <=temperature)
{
relayControl(relayON);
}
}
//Robojax.com heater/cooler with MAX6675 Thermocoupler
}//loadControl()
/*
* relayControl(int state))
* @brief turns the relay ON or OFF
* @param state is "relayON" or "relayOFF" defined at the top of code
* @return returns none
* Written by Ahmad Shamshiri for robojax.com
* on May 20, 2020 at 15:23 in Ajax, Ontario, Canada
*/
void relayControl(int state)
{
//Robojax.com heater/cooler with MAX6675 Thermocoupler
if(state ==relayON)
{
digitalWrite(relayPin, relayON);
Serial.println("Relay ON");
}else{
digitalWrite(relayPin, relayOFF);
Serial.println("Relay OFF");
}
//Robojax.com heater/cooler with MAX6675 Thermocoupler
}//relayControl()
/*
* readTemperature()
* @brief reads the temperature based on the TEMPERATURE_UNIT
* @param average temperature
* @return returns one of the values above
* Written by Ahmad Shamshiri for robojax.com
* on May 20, 2020 at 15:23 in Ajax, Ontario, Canada
*/
void readTemperature()
{
//Robojax.com heater/cooler with MAX6675 Thermocoupler
if(TEMPERATURE_UNIT ==2)
{
temperature = thermocouple.readFahrenheit();//convert to Fahrenheit
}else if(TEMPERATURE_UNIT ==3)
{
temperature = thermocouple.readCelsius() + 273.15;//convert to Kelvin
}else{
temperature = thermocouple.readCelsius();// return Celsius
}
//Robojax.com heater/cooler with MAX6675 Thermocoupler
}// readTemperature()
/*
* printTemperature()
* @brief prints temperature on serial monitor
* @param charact type
* @param "type" is character
* C = Celsius
* K = Kelvin
* F = Fahrenheit
* @return none
* Written by Ahmad Shamshiri for robojax.com
* on May 08, 2020 at 02:45 in Ajax, Ontario, Canada
*/
void printTemperature()
{
//Robojax.com heater/cooler with MAX6675 Thermocoupler
Serial.print(temperature);
printDegree();
if(TEMPERATURE_UNIT ==2)
{
Serial.print("F");
}else if(TEMPERATURE_UNIT ==3)
{
Serial.print("K");
}else{
Serial.print("C");
}
Serial.println();
//Robojax.com heater/cooler with MAX6675 Thermocoupler
}//printTemperature()
/*
* @brief prints degree symbol on serial monitor
* @param none
* @return returns nothing
* Written by Ahmad Shamshiri on July 13, 2019
* for Robojax Tutorial Robojax.com
*/
void printDegree()
{
Serial.print("\\xC2");
Serial.print("\\xB0");
}
Things you might need
-
eBay
-
AliExpressPurchase 1 channel 5V KY-019 relay from AliExpresss.click.aliexpress.com
-
BanggoodPurchase MAX6675 K-Type from Banggoodbanggood.com
Resources & references
-
ExternalMAX6675 datasheet (PDF)datasheets.maximintegrated.com
Files📁
No files available.