Circuit Documentation

Summary

This document provides a detailed overview of a Woman Safety Device circuit. The circuit includes various components such as a NodeMCU ESP8266, OLED Display, SIM800L GSM Module, Neo6MV2 GPS Module, Buzzer, LEDs, and other supporting components. The device is designed to send an emergency alert when a button is pressed.

Component List

1. NodeMCU ESP8266

   • Description: A microcontroller with built-in Wi-Fi capabilities.
   • Pins: D0, D1, D2, D3, D4, 3V3, GND, D5, D6, D7, D8, RX, TX, A0, RSV, SD3, SD2, SD1, CMD, SD0, CLK, EN, RST, VIN

2. 7.4V Battery

   • Description: Power source for the circuit.
   • Pins: +, -

3. 7805 Voltage Regulator

   • Description: Regulates the voltage to 5V.
   • Pins: Vin, Gnd, Vout

4. Ceramic Capacitor

   • Description: Provides noise filtering and stability.
   • Pins: pin0, pin1
   • Properties: Capacitance: 0.1 Farads

5. Tantalum Capacitor

   • Description: Provides noise filtering and stability.
   • Pins: -, +
   • Properties: Capacitance: 0.22 Farads

6. 0.96" OLED Display

   • Description: Displays information.
   • Pins: GND, VDD, SCK, SDA

7. SIM800L GSM Module

   • Description: Sends SMS alerts.
   • Pins: NET, RST, VCC, RXD, TXD, GND

8. GPS NEO 6M

   • Description: Provides GPS location data.
   • Pins: VCC, RX, TX, GND

9. LM2596 Voltage Regulator

   • Description: Regulates the voltage.
   • Pins: IN, OUT

10. Buzzer

    • Description: Provides audible alerts.
    • Pins: PIN, GND

11. Resistor (200 Ohms)

    • Description: Limits current.
    • Pins: pin1, pin2
    • Properties: Resistance: 200 Ohms

12. Resistor (1000 Ohms)

    • Description: Limits current.
    • Pins: pin1, pin2
    • Properties: Resistance: 1000 Ohms

13. Electrolytic Capacitor

    • Description: Provides noise filtering and stability.
    • Pins: -, +
    • Properties: Capacitance: 0.000001 Farads

14. Pushbutton

    • Description: User input for triggering alerts.
    • Pins: Pin 3 (out), Pin 4 (out), Pin 1 (in), Pin 2 (in)

15. LED: Two Pin (red)

    • Description: Visual indicator.
    • Pins: cathode, anode

Wiring Details

NodeMCU ESP8266

• D1: Connected to SCK of OLED Display
• D2: Connected to SDA of OLED Display and PIN of Buzzer
• D3: Connected to pin2 of 1000 Ohms Resistor
• D5: Connected to RX of GPS NEO 6M
• D6: Connected to TX of GPS NEO 6M
• D7: Connected to Pin 4 (out) of Pushbutton
• RX: Connected to RXD of SIM800L
• TX: Connected to TXD of SIM800L
• 3V3: Connected to VDD of OLED Display
• GND: Connected to cathode of LED (red)
• VIN: Connected to pin1 of Ceramic Capacitor, VCC of GPS NEO 6M, and Vout of 7805 Voltage Regulator

7.4V Battery

• +: Connected to Vin of 7805 Voltage Regulator and IN of LM2596
• -: Connected to GND of various components

7805 Voltage Regulator

• Vin: Connected to + of 7.4V Battery
• Gnd: Connected to GND of various components
• Vout: Connected to - of Tantalum Capacitor, VCC of GPS NEO 6M, and VIN of NodeMCU ESP8266

Ceramic Capacitor

• pin0: Connected to GND
• pin1: Connected to VIN of NodeMCU ESP8266

Tantalum Capacitor

• -: Connected to Vout of 7805 Voltage Regulator
• +: Connected to GND

0.96" OLED Display

• GND: Connected to GND
• VDD: Connected to 3V3 of NodeMCU ESP8266
• SCK: Connected to D1 of NodeMCU ESP8266
• SDA: Connected to D2 of NodeMCU ESP8266

SIM800L GSM Module

• RXD: Connected to RX of NodeMCU ESP8266
• TXD: Connected to TX of NodeMCU ESP8266
• VCC: Connected to + of Electrolytic Capacitor and OUT of LM2596
• GND: Connected to GND

GPS NEO 6M

• RX: Connected to D5 of NodeMCU ESP8266
• TX: Connected to D6 of NodeMCU ESP8266
• VCC: Connected to Vout of 7805 Voltage Regulator
• GND: Connected to GND

LM2596 Voltage Regulator

• IN: Connected to + of 7.4V Battery
• OUT: Connected to + of Electrolytic Capacitor and VCC of SIM800L

Buzzer

• PIN: Connected to D2 of NodeMCU ESP8266
• GND: Connected to GND

Resistor (200 Ohms)

• pin1: Connected to anode of LED (red)
• pin2: Connected to D3 of NodeMCU ESP8266

Resistor (1000 Ohms)

• pin1: Connected to anode of LED (red)
• pin2: Connected to D3 of NodeMCU ESP8266

Electrolytic Capacitor

• -: Connected to GND
• +: Connected to OUT of LM2596

Pushbutton

• Pin 3 (out): Not connected
• Pin 4 (out): Connected to D7 of NodeMCU ESP8266
• Pin 1 (in): Connected to GND
• Pin 2 (in): Not connected

LED: Two Pin (red)

• cathode: Connected to GND
• anode: Connected to pin1 of 1000 Ohms Resistor

Documented Code

NodeMCU ESP8266 Code

/*
 * Woman Safety Device
 * Components: NodeMCU ESP8266, OLED Display, SIM800L GSM Module,
 * Neo6MV2 GPS Module, Buzzer, LEDs (Red, Red, Blue)
 * Functionality: This code initializes the components and provides
 * basic functionality for the safety device.
 */

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <SoftwareSerial.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

SoftwareSerial sim800l(D1, D2); // RX, TX

#define BUZZER_PIN D7
#define SWITCH_PIN D2

void setup() {
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(SWITCH_PIN, INPUT);
  digitalWrite(BUZZER_PIN, LOW);

  Serial.begin(115200);
  sim800l.begin(9600);

  if(!display.begin(SSD1306_I2C_ADDRESS, OLED_RESET)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  display.display();
  delay(2000);
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println(F("Woman Safety Device"));
  display.display();
}

void loop() {
  if(digitalRead(SWITCH_PIN) == HIGH) {
    digitalWrite(BUZZER_PIN, HIGH);
    sendAlert();
  } else {
    digitalWrite(BUZZER_PIN, LOW);
  }
}

void sendAlert() {
  sim800l.println("AT+CMGF=1");
  delay(1000);
  sim800l.println("AT+CMGS=\"+1234567890\"");
  delay(1000);
  sim800l.print("