Circuit Documentation

Summary

This circuit is designed to control a valve, pump, and fan based on temperature readings from multiple thermocouple amplifiers. The temperature data is logged to an SD card. Additionally, a current sensor is used to monitor the current and control the relays. The circuit is managed by an Arduino Mega 2560 microcontroller.

Component List

1. Valve

   • Pins: GND, DCIN
   • Description: Controls the flow of a fluid or gas.

2. 1 Channel Relay 5V

   • Pins: VCC, GND, IN, NC, COM, NO
   • Description: Used to control high voltage devices with a low voltage signal.

3. 120V Outlet

   • Pins: AC Neutral, AC Hot, GND
   • Description: Standard electrical outlet for 120V AC devices.

4. Pump

   • Pins: in, -VE, ground
   • Description: Used to move fluids.

5. Power Supply

   • Pins: +, -, GND
   • Description: Provides power to the circuit.

6. Current Sensor 5A

   • Pins: 1, 2, GND, OUT, VCC
   • Description: Measures the current flowing through the circuit.

7. Adafruit Thermocouple Amplifier MAX31855

   • Pins: VIN, +3V3, THERMO-, GND, DO, THERMO+, CS, CLK
   • Description: Amplifies the signal from a thermocouple for temperature measurement.

8. Arduino Mega 2560

   • Pins: IOREF, RESET, 3V3, 5V, GND, VIN, A0-A15, D0-D53, SDA, SCL, AREF
   • Description: Microcontroller used to control the circuit.

9. Adafruit MicroSD card breakout board

   • Pins: VCC, +3V3, GND, CLK, DO, DI, CS, CD
   • Description: Used to log data to an SD card.

10. Fan

    • Pins: +ve, grnd, -ve
    • Description: Used for cooling purposes.

11. AC

    • Pins: +ve, grnd, -ve
    • Description: Air conditioning unit.

12. 18650 Li-Ion Battery

    • Pins: Positive, Negative
    • Description: Rechargeable lithium-ion battery.

Wiring Details

Valve

• GND: Connected to Power Supply (-)
• DCIN: Connected to 1 Channel Relay 5V (NO)

1 Channel Relay 5V

• VCC: Connected to Arduino Mega 2560 (5V)
• GND: Connected to common ground
• IN:
  • Relay 1: Connected to Arduino Mega 2560 (D36)
  • Relay 2: Connected to Arduino Mega 2560 (D37)
  • Relay 3: Connected to Arduino Mega 2560 (D38)
• NC: Not connected
• COM:
  • Relay 1: Connected to Power Supply (+)
  • Relay 2: Connected to 120V Outlet (AC Hot)
  • Relay 3: Connected to 120V Outlet (AC Hot)
• NO:
  • Relay 1: Connected to Valve (DCIN)
  • Relay 2: Connected to Pump (in)
  • Relay 3: Connected to Fan (+ve)

120V Outlet

• AC Neutral:
  • Outlet 1: Connected to Pump (-VE)
  • Outlet 2: Connected to Fan (-ve)
  • Outlet 3: Connected to AC (grnd)
• AC Hot:
  • Outlet 1: Connected to 1 Channel Relay 5V (COM)
  • Outlet 2: Connected to 1 Channel Relay 5V (COM)
  • Outlet 3: Connected to AC (+ve)
• GND:
  • Outlet 1: Connected to Pump (ground)
  • Outlet 2: Connected to Fan (grnd)
  • Outlet 3: Connected to AC (-ve)

Pump

• in: Connected to 1 Channel Relay 5V (NO)
• -VE: Connected to 120V Outlet (AC Neutral)
• ground: Connected to 120V Outlet (GND)

Power Supply

• +: Connected to 1 Channel Relay 5V (COM)
• -: Connected to Valve (GND)
• GND: Common ground

Current Sensor 5A

• 1: Connected to 1 Channel Relay 5V (NO)
• 2: Connected to 120V Outlet (AC Neutral)
• GND: Common ground
• OUT: Connected to Arduino Mega 2560 (D2 PWM)
• VCC: Connected to Arduino Mega 2560 (5V)

Adafruit Thermocouple Amplifier MAX31855

• VIN: Connected to Arduino Mega 2560 (5V)
• +3V3: Not connected
• THERMO-: Not connected
• GND: Common ground
• DO: Connected to Arduino Mega 2560 (D50)
• THERMO+: Not connected
• CS:
  • Thermocouple 1: Connected to Arduino Mega 2560 (D22)
  • Thermocouple 2: Connected to Arduino Mega 2560 (D23)
  • Thermocouple 3: Connected to Arduino Mega 2560 (D24)
  • Thermocouple 4: Connected to Arduino Mega 2560 (D25)
  • Thermocouple 5: Connected to Arduino Mega 2560 (D26)
  • Thermocouple 6: Connected to Arduino Mega 2560 (D27)
  • Thermocouple 7: Connected to Arduino Mega 2560 (D28)
• CLK: Connected to Arduino Mega 2560 (D52)

Arduino Mega 2560

• 5V: Connected to various components requiring 5V
• GND: Common ground
• D2 PWM: Connected to Current Sensor 5A (OUT)
• D22-D28: Connected to Adafruit Thermocouple Amplifier MAX31855 (CS)
• D36-D38: Connected to 1 Channel Relay 5V (IN)
• D50: Connected to Adafruit Thermocouple Amplifier MAX31855 (DO)
• D52: Connected to Adafruit Thermocouple Amplifier MAX31855 (CLK)
• D53: Connected to Adafruit MicroSD card breakout board (CS)

Adafruit MicroSD card breakout board

• VCC: Connected to Arduino Mega 2560 (5V)
• +3V3: Not connected
• GND: Common ground
• CLK: Connected to Arduino Mega 2560 (D52)
• DO: Connected to Arduino Mega 2560 (D50)
• DI: Connected to Arduino Mega 2560 (D51)
• CS: Connected to Arduino Mega 2560 (D53)
• CD: Not connected

Fan

• +ve: Connected to 1 Channel Relay 5V (NO)
• grnd: Connected to 120V Outlet (GND)
• -ve: Connected to 120V Outlet (AC Neutral)

AC

• +ve: Connected to 120V Outlet (AC Hot)
• grnd: Connected to 120V Outlet (AC Neutral)
• -ve: Connected to 120V Outlet (GND)

18650 Li-Ion Battery

• Positive: Connected to 45 (+ve)
• Negative: Connected to 45 (-ve)

Code Documentation

/*
 * Arduino Sketch for controlling a valve, pump, and fan based on temperature
 * readings from multiple thermocouple amplifiers. The temperature data is
 * logged to an SD card. The current sensor is also read and used to control
 * the relays.
 */

#include <SPI.h>
#include <SD.h>
#include <Adafruit_MAX31855.h>

// Pin definitions
#define RELAY1_PIN 36
#define RELAY2_PIN 37
#define RELAY3_PIN 38
#define CURRENT_SENSOR_PIN 2
#define SD_CS_PIN 53

// Thermocouple amplifier pins
#define THERMO_CS1 22
#define THERMO_CS2 23
#define THERMO_CS3 24
#define THERMO_CS4 25
#define THERMO_CS5 26
#define THERMO_CS6 27
#define THERMO_CS7 28

// Create thermocouple objects
Adafruit_MAX31855 thermocouple1(THERMO_CS1);
Adafruit_MAX31855 thermocouple2(THERMO_CS2);
Adafruit_MAX31855 thermocouple3(THERMO_CS3);
Adafruit_MAX31855 thermocouple4(THERMO_CS4);
Adafruit_MAX31855 thermocouple5(THERMO_CS5);