Circuit Documentation

Summary

This document provides a detailed overview of a circuit designed to interface various sensors, actuators, and modules with a Raspberry Pi 4B microcontroller. The circuit includes components for sensing temperature, humidity, and distance, as well as controlling water pumps and a solenoid valve. Communication with some sensors is facilitated by an ADS1115 analog-to-digital converter and an RS485 transceiver. A logic level converter is used to interface 3.3V and 5V logic levels, and a motor driver controls the pumps. Power is supplied by a 12V power supply, and a 2-channel relay module is included for switching high-power devices.

Component List

• Raspberry Pi 4B: A microcontroller board with multiple GPIO pins for interfacing with various components.
• Mini Diaphragm Water Pump: A pump for moving water, controlled by the motor driver.
• L298N DC Motor Driver: A module for controlling DC motors, used here to control the water pumps.
• 12V Power Supply: Provides power to the motor driver and the 12V rail of the circuit.
• Terminal Blocks: Used for organizing and connecting wires in the circuit.
• AM2302 Humidity and Temperature Sensor: Measures ambient temperature and humidity.
• 5V Mini Water Pump: Another pump for moving water, also controlled by the motor driver.
• Plastic Solenoid Valve: An electrically-controlled valve for controlling fluid flow.
• HC-SR04 Ultrasonic Sensors: Measure distance by emitting and receiving ultrasonic waves.
• 2-Channel Relay Module: Allows the Raspberry Pi to control high-power devices.
• DFRobot EC Sensor: Measures the electrical conductivity of a solution, indicative of its salt concentration.
• ADS1115: A 16-bit analog-to-digital converter for reading analog sensors.
• Adafruit TXB0108 8-Channel Bi-Directional Logic Level Converter: Converts logic levels between 3.3V and 5V.
• pH Degree Sensor Module: Measures the pH level of a solution.
• NPK Soil Sensor: Measures the nitrogen, phosphorus, and potassium content in soil.
• RS485 Transceiver: Facilitates RS485 communication for long-distance and differential signaling.
• Potentiometer: A variable resistor, typically used for adjusting a parameter or as a sensor input.

Wiring Details

Raspberry Pi 4B

• 3V3: Logic level converter (VCCA)
• 5V: Powers various 5V components and sensors
• GPIO2 (SDA): Connected to ADS1115 (SDA)
• GPIO3 (SCL): Connected to ADS1115 (SCL)
• GPIO4: Not connected
• GPIO14: Not connected
• GPIO15: Connected to RS485 (DI)
• GPIO17: Connected to AM2302 (DATA)
• GPIO18: Not connected
• GPIO27: Connected to logic level converter (A3)
• GPIO22: Connected to logic level converter (A8)
• GPIO23: Not connected
• GPIO24: Not connected
• GPIO10: Not connected
• GPIO9: Not connected
• GPIO25: Not connected
• GPIO11: Not connected
• GPIO8: Not connected
• GPIO7: Not connected
• ID_SD: Not connected
• GPIO5: Connected to logic level converter (A4)
• GPIO6: Connected to logic level converter (A5)
• GPIO12: Connected to RS485 (RE/DE)
• GPIO13: Connected to logic level converter (A6)
• GPIO19: Connected to logic level converter (A7)
• GPIO16: Connected to RS485 (RO)
• GPIO26: Not connected
• GPIO20: Connected to logic level converter (A1)
• GPIO21: Connected to logic level converter (A2)
• GND: Common ground for the circuit

Mini Diaphragm Water Pump

• Positive (+): Connected to L298N (OUT2)
• Negative (-): Connected to L298N (OUT1)

L298N DC Motor Driver

• OUT1, OUT2: Connected to Mini Diaphragm Water Pump
• 12V: Connected to 12V power supply through terminal block
• GND: Connected to GND rail through terminal block
• 5V: Not connected
• OUT3, OUT4: Connected to 5V Mini Water Pump
• ENA, IN1, IN3: Controlled by logic level converter
• ENB: Controlled by logic level converter

12V Power Supply

• (+): Connected to L298N (12V) and relay module (VCC+) through terminal block
• (-): Connected to GND rail through terminal block

Terminal Blocks

• Used to distribute power and ground connections

AM2302 Humidity and Temperature Sensor

• VDD: Connected to 5V rail
• DATA: Connected to Raspberry Pi (GPIO17)
• GND: Connected to GND rail

5V Mini Water Pump

• Positive pin: Connected to L298N (OUT4)
• Negative pin: Connected to L298N (OUT3)

Plastic Solenoid Valve

• Pin1: Connected to GND rail through relay module (COM 1)
• Pin2: Connected to relay module (N.O. 1)

HC-SR04 Ultrasonic Sensors

• VCC: Connected to 5V rail
• TRIG: Controlled by logic level converter
• ECHO: Connected to logic level converter
• GND: Connected to GND rail

2-Channel Relay Module

• COM 1, COM 2: Connected to GND rail through terminal block
• N.O. 1: Connected to Solenoid Valve (Pin2)
• VCC+: Connected to 12V power supply
• VCC- (GND): Connected to GND rail
• IN 1, IN 2: Controlled by logic level converter

DFRobot EC Sensor

• (+): Connected to 5V rail
• (-): Connected to GND rail
• A: Connected to ADS1115 (A0)

ADS1115

• VDD: Connected to 5V rail
• GND: Connected to GND rail
• SCL: Connected to Raspberry Pi (GPIO3)
• SDA: Connected to Raspberry Pi (GPIO2)
• A0: Connected to EC Sensor (A)
• A1: Connected to pH Sensor (pH A)
• A2: Connected to Potentiometer (Output)

Adafruit TXB0108 8-Channel Bi-Directional Logic Level Converter

• VCCB: Connected to 5V rail
• OE, GND: Connected to GND rail
• VCCA: Connected to Raspberry Pi (3V3)
• A1-A8: Connected to various Raspberry Pi GPIOs
• B1-B8: Connected to various components requiring level shifting

pH Degree Sensor Module

• pH Positive: Connected to 5V rail
• pH Negative: Connected to GND rail
• pH A: Connected to ADS1115 (A1)

NPK Soil Sensor

• VCC: Connected to 5V rail
• GND: Connected to RS485 (B)
• A: Connected to RS485 (A)

RS485 Transceiver

• VCC: Connected to 5V rail
• RO: Connected to Raspberry Pi (GPIO16)
• RE/DE: Connected to Raspberry Pi (GPIO12)
• GND: Connected to GND rail
• B: Connected to NPK Soil Sensor (GND)
• A: Connected to NPK Soil Sensor (A)

Potentiometer

• VCC: Connected to 5V rail
• Output: Connected to ADS1115 (A2)
• GND: Connected to GND rail

Documented Code

Raspberry Pi 4B - sketch.ino

void setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}

Raspberry Pi 4B - documentation.txt

(No additional documentation provided for this file)

This concludes the documentation for the circuit. The wiring details provide a comprehensive guide for connecting the components, and the code section includes the initialization and main loop for the Raspberry Pi 4B microcontroller.