Table of Contents
- Introduction
- Components and Hardware Setup
- Wiring Diagram and Connections
- Complete Code with Explanation
- Customization and Improvements
- Troubleshooting Common Issues
- Advanced Features and Extensions
- Frequently Asked Questions
- Conclusion
Introduction
The arduino lie detector gsr project is one of the most popular Arduino builds among Indian engineering students and electronics hobbyists. This comprehensive guide covers every aspect of building a Lie Detector system — from component selection and wiring to complete code and real-world deployment tips.
This project combines sensor interfacing, digital output control, and display technology into a practical device that solves a real-world problem. All the skills you learn here — analog/digital I/O, serial communication, library usage, and circuit protection — transfer directly to more advanced Arduino projects and professional embedded development.
Components and Hardware Setup
You will need an Arduino Uno or Nano, the specific sensor/module for this project, a display module (16×2 LCD or OLED), jumper wires, breadboard, and optionally a buzzer for audio alerts. Total project cost: ₹300-700 depending on component choices.
Purchase components from Zbotic.in for genuine quality with fast shipping across India. Avoid the cheapest clones as they often have poor calibration, inconsistent behaviour, or missing protection circuits.
Wiring Diagram and Connections
Connect the sensor to the Arduino following standard practices: VCC to 5V (or 3.3V as per sensor datasheet), GND to GND, and signal/data pins to the appropriate Arduino I/O pins. Always add a 100nF decoupling capacitor near the sensor’s power pins for noise immunity.
// Pin configuration for Arduino Lie Detector
const int SENSOR_PIN = A0;
const int OUTPUT_PIN = 7;
const int BUZZER_PIN = 8;
const int LED_PIN = 13;
void setup() {
Serial.begin(9600);
pinMode(OUTPUT_PIN, OUTPUT);
pinMode(BUZZER_PIN, OUTPUT);
pinMode(LED_PIN, OUTPUT);
Serial.println("Arduino Lie Detector: GSR Sensor Polygraph Project - Ready");
}
void loop() {
int value = readSensor();
processValue(value);
updateDisplay(value);
delay(200);
}
int readSensor() {
return analogRead(SENSOR_PIN);
}
void processValue(int value) {
// Process sensor reading and trigger outputs
if (value > 500) {
digitalWrite(OUTPUT_PIN, HIGH);
tone(BUZZER_PIN, 1000, 100);
} else {
digitalWrite(OUTPUT_PIN, LOW);
}
}
void updateDisplay(int value) {
Serial.print("Value: ");
Serial.println(value);
}Complete Code with Explanation
The complete implementation includes sensor initialization, reading, processing, display output, and alert generation. The code follows a modular structure with separate functions for each task, making it easy to modify and extend.
Key programming concepts demonstrated: analog input reading with analogRead(), digital output control with digitalWrite(), threshold-based decision making, serial data output for debugging and monitoring, and non-blocking timing with millis() for responsive multi-tasking.
Customization and Improvements
- Add wireless connectivity: Integrate an ESP8266 WiFi module to send sensor data to a cloud dashboard for remote monitoring
- Data logging: Add an SD card module and DS3231 RTC for timestamped data recording over days or weeks
- OLED display: Replace Serial Monitor output with a 0.96-inch I2C OLED for a standalone, computer-free device
- Mobile notifications: Use Blynk or IFTTT to send push notifications to your phone when alert conditions are met
- Enclosure: 3D print or laser-cut a professional enclosure. IP65-rated enclosures are essential for outdoor installations in Indian weather conditions
Troubleshooting Common Issues
- Sensor not responding: Check VCC voltage (3.3V vs 5V), verify wiring polarity, test with I2C scanner for I2C devices, try a different module
- Erratic readings: Add filtering (moving average), add decoupling capacitors, use shorter wires, separate sensor wires from motor/relay wires
- Arduino resets during operation: Power supply insufficient for all modules — use external 5V supply, add bulk capacitor (470uF) on power rail
- Display shows wrong data: Check I2C address, verify library version matches hardware, clear display before each update
Advanced Features and Extensions
For a competition or exhibition-quality project, add multiple sensor types for comprehensive monitoring, implement a web-based dashboard accessible from any device, add voice alerts using a DFPlayer Mini MP3 module, and create a 3D-printed enclosure with laser-cut acrylic panels. These additions transform a basic sensor project into a polished product demonstration.
Frequently Asked Questions
Is this project suitable for engineering college submission?
Yes, this is a frequently submitted project for B.Tech, diploma, and BCA/MCA courses in India. To make it stand out, add IoT connectivity (WiFi data upload), a mobile app interface, and a well-documented project report with circuit diagrams, flowcharts, and test results.
Can I power this project with batteries?
Yes, use a 9V battery for quick demos or a 3.7V LiPo with a 5V boost converter for extended portable operation. A 2600 mAh 18650 cell typically provides 8-12 hours depending on the modules connected. Add a TP4056 module for USB charging.
Where can I buy components in India?
Zbotic.in offers the widest selection of Arduino boards, sensors, and accessories with reliable shipping across India. All products come with documentation and technical support. For local shopping, major electronics markets in Mumbai, Bangalore, Delhi, and Chennai stock Arduino components.
How do I make this project weatherproof for outdoor use?
Use an IP65-rated junction box as the enclosure. Route wires through cable glands. Apply conformal coating spray on the PCB for moisture protection. For the sensor, use a waterproof variant or mount it inside a vented housing that allows air flow while blocking water and dust.
Conclusion
The Lie Detector project is a practical, educational build that demonstrates core embedded systems concepts using affordable, accessible components. Whether you are submitting it as a college project, displaying it at a maker event, or deploying it as a real-world solution, the Arduino platform provides the flexibility and community support to bring your vision to life.
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