Circuit Documentation

Summary

This circuit is designed to interface an Arduino UNO with a SIM800L GSM Module, a Neo 6M GPS Module, and a pushbutton. The purpose of the circuit is to send an SMS message with GPS location data when the pushbutton is pressed. The Arduino UNO acts as the central processing unit, reading GPS data from the Neo 6M GPS Module and sending SMS messages through the SIM800L GSM Module. A resistor is used for pull-up configuration on the pushbutton. The 9V battery provides power to the SIM800L GSM 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.

Pushbutton

• A simple switch mechanism for controlling some aspect of a machine or a process. Buttons are typically made out of hard material, usually plastic or metal.

SIM800L GSM Module

• A complete Quad-band GSM/GPRS solution in an LGA package, which can be embedded in customer applications.

Resistor

• A passive two-terminal electrical component that implements electrical resistance as a circuit element. In this circuit, a 10,000 Ohms resistor is used.

9V Battery

• A standard size of dry cell battery commonly used in portable electronic devices.

Neo 6M GPS Module

• A standalone GPS receiver that features high performance u-blox 6 positioning engine.

Wiring Details

Arduino UNO

• 5V connected to Neo 6M GPS Module VCC and through a resistor to the pushbutton.
• GND connected to Neo 6M GPS Module GND, Pushbutton Pin 4, and SIM800L GSM Module GND.
• D2 connected to one side of the Pushbutton.
• D3 connected to Neo 6M GPS Module RX.
• D4 connected to Neo 6M GPS Module TX.
• D10 connected to SIM800L GSM Module SIM_TXD.
• D11 connected to SIM800L GSM Module SIM_RXD.

Pushbutton

• One side connected to Arduino UNO D2.
• The other side connected to Arduino UNO GND through a 10,000 Ohms resistor.

SIM800L GSM Module

• 5V connected to 9V Battery +.
• GND connected to 9V Battery -.
• SIM_TXD connected to Arduino UNO D10.
• SIM_RXD connected to Arduino UNO D11.

Resistor

• One side connected to Arduino UNO 5V.
• The other side connected to Pushbutton.

9V Battery

• + connected to SIM800L GSM Module 5V.
• - connected to SIM800L GSM Module GND.

Neo 6M GPS Module

• VCC connected to Arduino UNO 5V.
• GND connected to Arduino UNO GND.
• TX connected to Arduino UNO D4.
• RX connected to Arduino UNO D3.

Documented Code

#include <SoftwareSerial.h>
#include <TinyGPS++.h>

// Define pin numbers
const int buttonPin = 2;  // Push button connected to digital pin 2
const int gsmRxPin = 10;  // RX pin of GSM module
const int gsmTxPin = 11;  // TX pin of GSM module
const int gpsRxPin = 4;   // RX pin of GPS module
const int gpsTxPin = 3;   // TX pin of GPS module

// Create software serial objects
SoftwareSerial gsmSerial(gsmRxPin, gsmTxPin);
SoftwareSerial gpsSerial(gpsRxPin, gpsTxPin);

// Create a TinyGPS++ object
TinyGPSPlus gps;

// Variables
int buttonState = 0;
bool messageSent = false;
const char* phoneNumber = "+1234567890";  // Replace with the desired phone number
const char* message = "Emergency! Help needed at this location: ";

void setup() {
  Serial.begin(9600);
  gsmSerial.begin(9600);
  gpsSerial.begin(9600);
  
  pinMode(buttonPin, INPUT_PULLUP);
  
  // Initialize GSM module
  delay(1000);
  gsmSerial.println("AT");
  delay(1000);
  gsmSerial.println("AT+CMGF=1"); // Set SMS text mode
  delay(1000);
}

void loop() {
  // Update GPS data
  while (gpsSerial.available() > 0) {
    gps.encode(gpsSerial.read());
  }

  buttonState = digitalRead(buttonPin);

  if (buttonState == LOW && !messageSent) {
    sendSMS();
    messageSent = true;
  }
  
  if (buttonState == HIGH) {
    messageSent = false;
  }
}

void sendSMS() {
  Serial.println("Button pressed, sending SMS with location...");
  
  String locationMessage = message;
  
  if (gps.location.isValid()) {
    locationMessage += "http://maps.google.com/maps?q=";
    locationMessage += String(gps.location.lat(), 6);
    locationMessage += ",";
    locationMessage += String(gps.location.lng(), 6);
  } else {
    locationMessage += "GPS location not available";
  }
  
  // Send SMS
  gsmSerial.println("AT+CMGS=\"" + String(phoneNumber) + "\"");
  delay(1000);
  gsmSerial.print(locationMessage);
  delay(100);
  gsmSerial.write(26); // End SMS with Ctrl+Z character
  
  Serial.println("SMS sent with location!");
  delay(1000);
}

This code is designed to be uploaded to the Arduino UNO. It initializes the GSM and GPS modules, reads the button state, and sends an SMS with GPS coordinates when the button is pressed. The GPS data is obtained from the Neo 6M GPS Module, and the SMS is sent through the SIM800L GSM Module. The code uses the TinyGPS++ library to parse the GPS data and SoftwareSerial to communicate with the GSM and GPS modules.