Moving Robot Arm Controlled by Hand Gestures

Touchless Human-Robot Interaction Using Computer Vision & Wireless Communication

Duration:Nov 2023 - Apr 2024
Status:Completed
Category:Human-Robot Interaction
PythonPython
OpenCVOpenCV
ArduinoArduino
C++C++

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Project Overview

A human-computer interaction (HCI) project that enables touchless, intuitive control of a robotic manipulator. By leveraging computer vision and wireless communication, this system translates natural hand movements into precise mechanical actions in real-time, bridging the gap between digital gesture recognition and physical actuation.

The system eliminates physical controllers (joysticks/keyboards) by using a standard webcam to track hand movements, achieving 95%+ recognition accuracy while providing immediate visual feedback through skeletal overlay visualization.

Technical Architecture

Gesture Recognition Node

Computer vision pipeline running on host machine that captures video, tracks hand landmarks, and classifies gestures using MediaPipe

Communication Bridge

Wireless link using Bluetooth (HC-05) transmitting encoded command signals from host computer to robot controller

Robotic Control Node

Arduino-based embedded system that parses received commands and drives servo motors to replicate intended motion

Hardware Components

  • â–¸Arduino Uno: Central MCU for parsing commands and generating PWM signals
  • â–¸HC-05 Bluetooth: Wireless serial communication (~10m range)
  • â–¸Servo Motors (SG90/MG995): Precise angular positioning for joints
  • â–¸3-4 DOF Robotic Arm: Multi-joint chassis with base, shoulder, elbow, gripper
  • â–¸Mobile Wheeled Base: Adds mobility to manipulation capabilities

Software Stack

  • â–¸Python (OpenCV): Image processing and vision pipeline core
  • â–¸MediaPipe: Robust hand landmark detection (21 3D keypoints)
  • â–¸Arduino C/C++: Firmware for serial data interpretation
  • â–¸PySerial: Handles serial communication to Bluetooth COM port
  • â–¸Gesture Classification Logic: Analyzes finger landmark positions

Core Features & Capabilities

Real-Time Hand Gesture Recognition

95%+ recognition accuracy using MediaPipe's ML model to detect 21 3D hand keypoints with visual skeletal overlay feedback

Wireless Bluetooth Control

HC-05 module enables untethered operation with low-latency command transmission (~10m range)

Multi-DOF Control

Maps specific hand gestures to robotic axes: Index up (lift), Fist (grip), Open palm (release), Hand tilt (drive base)

Integrated Mobility

Wheeled chassis enables Pick and Place tasks with unified gesture interface for manipulation and navigation

Performance Specifications

95%+
Recognition Accuracy
~10 meters
Bluetooth Range
3-4 DOF
Degrees of Freedom
<100ms
Response Time

Implementation Highlights

🎯 Computer Vision Pipeline

Captures frames, converts to RGB, processes through MediaPipe Hands solution extracting 21 landmark coordinates. Custom logic calculates Euclidean distances between landmarks (e.g., thumb tip to index tip) for dynamic gesture recognition.

🤖 Inverse Kinematics (Simplified)

Translates abstract gestures into specific servo angles. For example, "V-sign" maps to "set servo 2 to 90 degrees" ensuring predictable movement patterns for intuitive control.

📡 Robust Serial Communication

Implements concise protocol sending single-character command bytes rather than complex strings. Arduino processes instructions within millisecond loop cycle required for smooth servo PWM generation.

Technical Challenges & Solutions

âš¡ Jitter & False Positives

✓ Implemented moving average smoothing filter and confidence threshold (min_detection_confidence=0.7) to ignore low-quality frames

âš¡ Power Supply Isolation

✓ Separate high-current power source for motors while keeping Arduino logic on stable regulated supply with shared common ground

âš¡ Latency Management

✓ Optimized Python loop with lower resolution (640x480) and increased Bluetooth baud rate (38400+) to maximize throughput

Real-World Applications

Prosthetics

Controlling artificial limbs using muscle signals or visual gestures

Industrial Safety

Operators control heavy machinery from safe distance without contact

Medical Robotics

Touchless control of surgical tools in sterile environments

Smart Home Automation

Control appliances using simple hand signs for elderly/disabled

Education & Research

Platform for HCI and robotics learning and experimentation

Entertainment

Interactive gaming and immersive gesture-based experiences

Future Enhancements

→Flex Sensor Integration: Add 'Smart Glove' for precise finger tracking
→Haptic Feedback: User 'feels' when robot grips objects
→Full IK Solver: True 1:1 motion tracking in 3D space
→Multi-hand Control: Support for bimanual manipulation tasks
→ML-based Gesture Learning: Custom gesture training interface
→Enhanced Mobility: Omnidirectional base with path planning

Project Impact

The Gesture-Controlled Robot Arm successfully demonstrates the power of integrating modern AI-based computer vision with classical embedded robotics. It creates a seamless, intuitive interface that makes controlling complex hardware as simple as waving a hand, highlighting the future of natural Human-Computer Interaction.

Interested in This Project?

This project demonstrates advanced human-robot interaction, computer vision, and wireless embedded systems. Feel free to reach out for collaboration or technical discussions.