An Arduino Uno (ATmega328P) project integrating an HC-05 module for low-latency wireless communication. Uses a 5V relay for active-LOW isolation and an L298N H-Bridge for bidirectional DC motor logic. Built with modular Embedded C firmware featuring real-time command parsing and terminal status tracking.
A hands-on hardware-software implementation demonstrating asynchronous terminal control over high-power peripherals. This system handles bidirectional communication using standard hardware Serial and software-defined serial communication (SoftwareSerial) to interface an HC-05/HC-06 Bluetooth module with an Arduino UNO microcontroller. It allows wireless or tethered real-time operation of an isolated DC motor and an electronic relay switch.
Developed as Lab (Open Ended Lab) for the Embedded Systems course under the Department of Computer Engineering at Pak-Austria Fachhochschule: Institute of Applied Sciences and Technology (PAF-IAST).
- Hoor Aman (Reg No:
B24F0225CE039) - Submitted To: Engr. Rafiullah
- Department: BS Computer Engineering
- Subject: Embedded Systems
- Optoisolated Switching: Utilizes an active-low 5V relay module to safely toggle a high-efficiency LED indicator circuit.
- State Preservation: Keeps track of the current operational state (
true/false) to toggle the relay cleanly without state overlapping.
- Dual-Bridge H-Bridge Control: Interfaces with an L298N dual H-bridge motor driver to change current direction through the motor coils.
- Full Motion Matrix: Supports dynamic runtime changes for Forward, Backward, and Hard Stop commands instantly via code routines.
- Simultaneous Listening: Features non-blocking polling loops that check both the physical USB hardware Serial port and the custom Bluetooth SoftwareSerial lines concurrently.
- Interactive Control Menu: Streams a clean, readable text-based Command Menu directly to the user's terminal upon system startup or when requested.
- Arduino UNO Microcontroller
- L298N Dual H-Bridge Motor Driver Module
- 5V SPDT Relay Module & LED Circuit Load
- HC-05 / HC-06 Bluetooth Serial Transceiver Module
- DC Toy Motor (5V-12V)
| Source Module | Component Pin | Arduino UNO Pin | Configuration / Notes |
|---|---|---|---|
| Bluetooth Module | TX Pin | Pin 10 (RX) | SoftwareSerial Receive Line |
| RX Pin | Pin 11 (TX) | SoftwareSerial Transmit Line | |
| Relay Driver | IN (Control) | Pin 7 | OUTPUT (Active LOW = Relay ON) |
| L298N H-Bridge | IN1 | Pin 4 | OUTPUT (Motor Direction Control A) |
| IN2 | Pin 3 | OUTPUT (Motor Direction Control B) | |
| ENA / ENB | Jumpered | Hardwired to 5V (Always Enabled) |
When connected to either the computer Arduino Serial Monitor (9600 Baud) or a smartphone Bluetooth Serial Terminal App (connected to the Bluetooth node module), use the following terminal inputs:
1: Turn LED ON (Sets Relay Control Pin LOW)0: Turn LED OFF (Sets Relay Control Pin HIGH)t/T: Toggle the LED dynamically based on its current runtime state
f/F: Rotate DC Motor Forward (IN1=HIGH, IN2=LOW)b/B: Rotate DC Motor Backward (IN1=LOW, IN2=HIGH)s/S: Stop Motor Instantly (IN1=LOW, IN2=LOW)
?: Request current peripheral vector diagnostic statusm/M: Re-print the main structural Control Menu text block
The system codebase is compiled using native C++ processing loops:
void handleCommand(char cmd) {
switch (cmd) {
// LED Control Vectors
case '1': digitalWrite(RELAY_PIN, LOW); ledState = true; break;
case '0': digitalWrite(RELAY_PIN, HIGH); ledState = false; break;
// Motor Motion Directives
case 'f': case 'F': motorForward(); break;
case 'b': case 'B': motorBackward(); break;
case 's': case 'S': stopMotor(); break;
// Telemetry Request
case '?': sendStatus(); break;
}
}