Circuit Documentation

Summary

This circuit integrates various components controlled by an Arduino Mega 2560 microcontroller to perform a range of functions. The circuit includes ultrasonic sensors (HC-SR04) for distance measurement, an I2C LCD screen for data display, a piezo sensor for detecting vibrations, a relay module for controlling power to a 12V geared motor, a SIM800L module for cellular communication, and a 12V battery as the power source.

Component List

Arduino Mega 2560

• Microcontroller board based on the ATmega2560
• It has 54 digital input/output pins, 16 analog inputs, 4 UARTs, a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button.

HC-SR04 Ultrasonic Sensor (x3)

• Ultrasonic distance measuring module
• Uses sonar to determine the distance to an object
• Features VCC, TRIG, ECHO, and GND pins

I2C LCD 16x2 Screen

• Alphanumeric liquid crystal display
• 16 characters wide, 2 rows
• Communicates over I2C protocol

Piezo Sensor

• Sensor that can detect vibration, touch, or shock
• Has a positive and a negative terminal

Relay Module 5V-30V

• Electrically operated switch
• Can be used to control higher power circuits with a low power signal
• Has common contact, normally open, normally closed, trigger, V-, and V+ pins

12V Geared Motor

• Electric motor with a gearbox for torque multiplication
• Has two terminals for electrical connection

SIM800L

• GSM/GPRS module
• Can be used for mobile communication such as sending SMS, making calls, etc.
• Features multiple pins including VCC, GND, RXD, TXD, etc.

12V Battery

• Power source for the motor and relay module
• Has a positive and a negative terminal

Wiring Details

Arduino Mega 2560

• 5V connected to VCC of I2C LCD, HC-SR04 sensors, Relay module, and SIM800L
• GND connected to GND of I2C LCD, HC-SR04 sensors, Relay module, SIM800L, and Piezo Sensor
• A1 connected to Piezo Sensor (-)
• D21/SCL connected to I2C LCD SCL
• D20/SDA connected to I2C LCD SDA
• D15/RX3 connected to SIM800L TXD
• D14/TX3 connected to SIM800L RXD
• D7 PWM connected to Relay module trigger
• D8 PWM connected to HC-SR04 ECHO (Sensor 2)
• D9 PWM connected to HC-SR04 TRIG (Sensor 2)
• D10 PWM connected to HC-SR04 ECHO (Sensor 3)
• D11 PWM connected to HC-SR04 TRIG (Sensor 3)
• D12 PWM connected to HC-SR04 ECHO (Sensor 1)
• D13 PWM connected to HC-SR04 TRIG (Sensor 1)

HC-SR04 Ultrasonic Sensor (Sensor 1)

• VCC connected to 5V from Arduino
• GND connected to GND from Arduino
• ECHO connected to D12 PWM on Arduino
• TRIG connected to D13 PWM on Arduino

HC-SR04 Ultrasonic Sensor (Sensor 2)

• VCC connected to 5V from Arduino
• GND connected to GND from Arduino
• ECHO connected to D8 PWM on Arduino
• TRIG connected to D9 PWM on Arduino

HC-SR04 Ultrasonic Sensor (Sensor 3)

• VCC connected to 5V from Arduino
• GND connected to GND from Arduino
• ECHO connected to D10 PWM on Arduino
• TRIG connected to D11 PWM on Arduino

I2C LCD 16x2 Screen

• VCC (5V) connected to 5V from Arduino
• GND connected to GND from Arduino
• SCL connected to D21/SCL on Arduino
• SDA connected to D20/SDA on Arduino

Piezo Sensor

• (+) connected to GND on Arduino (for simplicity in this example, though typically would connect to an I/O pin)
• (-) connected to A1 on Arduino

Relay Module 5V-30V

• V+ connected to 5V from Arduino
• V- connected to GND from Arduino
• Trigger connected to D7 PWM on Arduino
• Common contact connected to negative terminal of 12V Battery
• Normally open connected to Terminal 1 of 12V Geared Motor

12V Geared Motor

• Terminal 1 connected to normally open on Relay module
• Terminal 2 connected to positive terminal of 12V Battery

SIM800L

• VCC connected to 5V from Arduino
• GND connected to GND from Arduino
• TXD connected to D15/RX3 on Arduino
• RXD connected to D14/TX3 on Arduino

12V Battery

• (+) connected to Terminal 2 of 12V Geared Motor
• (-) connected to common contact of Relay module

Documented Code

Arduino Mega 2560 - sketch.ino

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

}

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

}

Arduino Mega 2560 - documentation.txt

(No additional documentation provided for the code)