Circuit Documentation

Summary

This document provides a detailed overview of a circuit that includes an Arduino Mega 2560 microcontroller, various sensors, a Bluetooth module, and an RS485 communication module. The circuit is designed to interface with soil sensors and communicate data wirelessly via Bluetooth and RS485.

Component List

1. Arduino Mega 2560

   • Description: A microcontroller board based on the ATmega2560.
   • Pins: IOREF, RESET, 3V3, 5V, GND, VIN, A0-A15, D0-D53, AREF, SDA, SCL

2. NPK Soil Sensor

   • Description: A sensor used to measure the nitrogen, phosphorus, and potassium levels in soil.
   • Pins: VCC, GND, A, B

3. LM393

   • Description: A voltage comparator.
   • Pins: A0, D0, GND, VCC

4. RS485

   • Description: A communication module for RS485 protocol.
   • Pins: VCC, RO, RE, GND, B, A, DE, DI

5. SparkFun Soil Moisture Sensor

   • Description: A sensor used to measure soil moisture levels.
   • Pins: VCC, GND, SIG

6. HC-05 Bluetooth Module

   • Description: A Bluetooth module for wireless communication.
   • Pins: Key, VCC, TXD, RXD, State, GND

7. Resistor

   • Description: A 200 Ohm resistor.
   • Pins: pin1, pin2

8. Battery 12V

   • Description: A 12V battery for power supply.
   • Pins: +, -

Wiring Details

Arduino Mega 2560

• 5V is connected to:

  • VCC of HC-05 Bluetooth Module
  • VCC of LM393
  • VCC of RS485

• GND is connected to:

  • pin2 of Resistor
  • GND of LM393
  • GND of RS485
  • GND of NPK Soil Sensor
  • GND of SparkFun Soil Moisture Sensor

• D0 RX0 is connected to RXD of HC-05 Bluetooth Module

• D1 TX0 is connected to TXD of HC-05 Bluetooth Module

• D2 PWM is connected to DE of RS485

• D3 PWM is connected to RE of RS485

• D4 PWM is connected to D0 of LM393

• D10 PWM is connected to DI of RS485

• D11 PWM is connected to RO of RS485

NPK Soil Sensor

• VCC is connected to + of Battery 12V
• GND is connected to GND of Arduino Mega 2560
• A is connected to A of RS485
• B is connected to B of RS485

LM393

• VCC is connected to 5V of Arduino Mega 2560
• GND is connected to GND of Arduino Mega 2560
• D0 is connected to D4 PWM of Arduino Mega 2560

RS485

• VCC is connected to 5V of Arduino Mega 2560
• GND is connected to GND of Arduino Mega 2560
• DE is connected to D2 PWM of Arduino Mega 2560
• RE is connected to D3 PWM of Arduino Mega 2560
• DI is connected to D10 PWM of Arduino Mega 2560
• RO is connected to D11 PWM of Arduino Mega 2560
• A is connected to A of NPK Soil Sensor
• B is connected to B of NPK Soil Sensor

SparkFun Soil Moisture Sensor

• VCC is connected to VCC of LM393
• GND is connected to GND of LM393

HC-05 Bluetooth Module

• VCC is connected to 5V of Arduino Mega 2560
• GND is connected to pin1 of Resistor
• RXD is connected to D0 RX0 of Arduino Mega 2560
• TXD is connected to D1 TX0 of Arduino Mega 2560

Resistor

• pin1 is connected to GND of HC-05 Bluetooth Module
• pin2 is connected to GND of Arduino Mega 2560

Battery 12V

• + is connected to VCC of NPK Soil Sensor
• - is connected to GND of Arduino Mega 2560

Documented Code

Arduino Mega 2560 Code

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

}

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

}

This code initializes the Arduino Mega 2560 and contains empty setup and loop functions, which can be filled with the necessary logic to interface with the connected sensors and modules.