PulsePatrol 📡

A real-time radar system built on a DE1-SoC FPGA (RISC-V soft core) paired with an Arduino. Detects and tracks objects using an ultrasonic sensor and displays them on a VGA radar display with object IDs.

Demo

https://drive.google.com/file/d/1yw48-4ZQUSW3I8U3Nc3RSThmJk4h5mVx/view?usp=sharing

System Architecture

Joystick (ADC) → Arduino → [GPIO Bit-Bang] → FPGA (RISC-V)
                                                    ↓
Servo Motor ←──────────────────────────────── VGA Display
HC-SR04 Sensor ────────────────────────────── HEX Displays
                                               LED Indicators

Hardware & I/O

Device	Role
HC-SR04 Ultrasonic Sensor	Distance measurement (2–400 cm)
Servo Motor	Physical angle sweep via joystick
Joystick (ADC)	Analog X/Y input via Arduino ADC
JP1 GPIO (3-wire)	DATA, CLOCK, SYNC bit-bang protocol
VGA Display	320×240 double-buffered radar output
HEX Displays	Shows live angle + distance
LEDs (LEDR)	Indicates active distance filter mode
KEY Buttons	KEY0 = hard reset, KEY1 = filter cycle

Features

• Joystick-controlled servo sweeps angle 0–180°
• Ultrasonic sensor reads distance up to 25 cm
• Custom 3-wire bit-bang GPIO protocol (SYNC/CLOCK/DATA) between Arduino and FPGA
• Blocking poll_packet() receiver on FPGA side
• Double-buffered VGA radar display with scanline
• Object tracking with confirmation threshold and miss expiry — filters out noise and false positives
• Numeric ID labels rendered via character buffer overlay (0x09000000, 80×60 grid)
• KEY0: hard reset — clears all tracked objects
• KEY1: cycles distance filter (25cm → 18cm → 10cm) with LED indicator

Tech Stack

• FPGA: DE1-SoC (RISC-V soft core via NIOS V)
• Microcontroller: Arduino Uno
• Languages: C (FPGA), C++ (Arduino)
• Display: VGA 320×240, character buffer overlay
• Communication: Custom bit-bang GPIO protocol

Project Structure

PulsePatrol/
├── arduino/
│   └── pulsepatrol.ino    # Joystick, servo, sensor, packet transmit
└── fpga/
    └── main.c             # Packet receive, object tracking, VGA render

How It Works

1. Arduino reads joystick angle and drives servo to that position
2. HC-SR04 fires ultrasonic pulse and measures return time
3. Arduino encodes (distance, angle) as a 16-bit packet and transmits via 3-wire bit-bang GPIO (SYNC/CLOCK/DATA)
4. FPGA polls JP1 pins, reconstructs the packet bit by bit on rising clock edges
5. Object tracker confirms detections after 8 consecutive hits, freezes position, and assigns an ID
6. VGA renderer draws radar arcs, scanline, confirmed object dots, and character ID labels each frame