Circuit Documentation

Summary

The circuit in question is designed around an Arduino UNO microcontroller and includes several peripheral components: an MPU-6050 accelerometer/gyroscope module, a SIM800L GSM module, a two-pin red LED, and a LoRa Ra-02 SX1278 module. The Arduino UNO serves as the central processing unit, interfacing with the MPU-6050 for motion detection, controlling the LED as an indicator, communicating with the SIM800L module for sending SMS messages, and handling LoRa communication through the SX1278 module.

Component List

Arduino UNO

• Microcontroller board based on the ATmega328P
• It has 14 digital input/output pins, 6 analog inputs, a 16 MHz quartz crystal, a USB connection, a power jack, an ICSP header, and a reset button.

MPU-6050

• A 6-axis motion tracking device that combines a 3-axis gyroscope and a 3-axis accelerometer on the same silicon die, along with an onboard Digital Motion Processor™ (DMP™) capable of processing complex 9-axis MotionFusion algorithms.

LED: Two Pin (red)

• A basic red LED with an anode and cathode for indicating statuses such as power or signal.

LoRa Ra-02 SX1278

• A wireless communication module that uses the LoRa (Long Range) protocol for long-distance data transmission.

SIM800L

• A GSM/GPRS module that allows for cellular network connectivity, enabling functions like SMS messaging and data transmission.

Wiring Details

Arduino UNO

• 3.3V connected to LoRa Ra-02 SX1278 3.3V
• 5V connected to SIM800L VCC and MPU-6050 VCC
• Multiple GND pins connected to SIM800L GND, MPU-6050 GND, LED anode, and LoRa Ra-02 SX1278 GND
• A4 (SDA) connected to MPU-6050 SDA
• A5 (SCL) connected to MPU-6050 SCL
• D13 connected to LED cathode and LoRa Ra-02 SX1278 SCK
• D12 connected to LoRa Ra-02 SX1278 MISO
• D11 connected to LoRa Ra-02 SX1278 MOSI
• D10 connected to LoRa Ra-02 SX1278 NSS
• D9 connected to LoRa Ra-02 SX1278 RST
• D8 connected to LoRa Ra-02 SX1278 DI00
• D4 connected to SIM800L RST
• D3 connected to SIM800L RXD
• D2 connected to SIM800L TXD

MPU-6050

• VCC connected to Arduino UNO 5V
• GND connected to Arduino UNO GND
• SCL connected to Arduino UNO A5
• SDA connected to Arduino UNO A4

LED: Two Pin (red)

• anode connected to Arduino UNO GND
• cathode connected to Arduino UNO D13

LoRa Ra-02 SX1278

• 3.3V connected to Arduino UNO 3.3V
• GND connected to Arduino UNO GND
• SCK connected to Arduino UNO D13
• MISO connected to Arduino UNO D12
• MOSI connected to Arduino UNO D11
• NSS connected to Arduino UNO D10
• RST connected to Arduino UNO D9
• DI00 connected to Arduino UNO D8

SIM800L

• VCC connected to Arduino UNO 5V
• GND connected to Arduino UNO GND
• RST connected to Arduino UNO D4
• RXD connected to Arduino UNO D3
• TXD connected to Arduino UNO D2

Documented Code

#include <Wire.h>
#include <MPU6050.h>
#include <SoftwareSerial.h>

MPU6050 mpu;
SoftwareSerial sim800(2, 3); // RX, TX
const int ledPin = 13;
const int threshold = 1000; // Adjust this threshold as needed

void setup() {
  pinMode(ledPin, OUTPUT);
  Wire.begin();
  Serial.begin(9600);
  sim800.begin(9600);
  mpu.initialize();
  if (!mpu.testConnection()) {
    Serial.println("MPU6050 connection failed");
    while (1);
  }
  Serial.println("MPU6050 connection successful");

  // Check SIM800L initialization
  sim800.print("AT\r");
  delay(100);
  if (sim800.available()) {
    String response = sim800.readString();
    if (response.indexOf("OK") == -1) {
      Serial.println("SIM800L initialization failed");
      while (1);
    }
  } else {
    Serial.println("SIM800L not responding");
    while (1);
  }

  sendSMS("System Initialized");
}

void loop() {
  int16_t ax, ay, az;
  mpu.getAcceleration(&ax, &ay, &az);
  int magnitude = sqrt(ax * ax + ay * ay + az * az);
  if (magnitude > threshold) {
    blinkLED();
    sendSMS("Movement detected!");
    delay(5000); // Wait 5 seconds before checking again
  }
  delay(100);
}

void blinkLED() {
  digitalWrite(ledPin, HIGH);
  delay(500);
  digitalWrite(ledPin, LOW);
  delay(500);
}

void sendSMS(const char* message) {
  sim800.print("AT+CMGF=1\r");
  delay(100);
  sim800.print("AT+CMGS=\"+1234567890\"\r"); // Replace with your phone number
  delay(100);
  sim800.print(message);
  delay(100);
  sim800.write(26); // ASCII code for CTRL+Z
  delay(1000); // Increased delay to ensure message is sent

  // Check if the message was sent successfully
  if (sim800.available()) {
    String response = sim800.readString();
    if (response.indexOf("OK") == -1) {
      Serial.println("Failed to send SMS");
    } else {
      Serial.println("SMS sent successfully");
    }
  } else {
    Serial.println("No response from SIM800L");
  }
}

This code is designed to run on the Arduino UNO and interfaces with the MPU-6050 to detect motion, controls an LED as an indicator, communicates with the SIM800L module to send SMS messages, and sets up the initial state of the LoRa SX1278 module. The code includes initialization checks for both the MPU-6050 and SIM800L to ensure proper startup and functionality.