Sensor-based Strength Training Tracking System
Strength training still largely relies on manual logging, limiting quantitative feedback and data-driven coaching. Beginners often struggle to learn correct exercise techniques, while experienced users and trainers face challenges in systematically analyzing and managing workout data. This project proposes an integrated strength training tracking system that connects sensor-based measurement devices with a mobile application to provide real-time monitoring, in-exercise feedback, and post-exercise analysis and visualization.
Questions
Q1. How can workout data be accurately measured across different machine structures?
- Pin-loaded machines (linear motion) vs. plate-loaded machines (rotational load)
- Multi-dimensional data: weight, repetitions, velocity, range of motion
- Sensor stability under vibration and impact during exercise
Q2. How can real-time feedback be effectively provided during workouts?
- Immediate feedback on speed, rhythm, and movement quality
- Personalized guidance based on user goals (e.g., hypertrophy, rehabilitation, weight loss)
- Enabling self-guided training without a trainer
Q3. How can interaction between machine, user, and mobile be seamless?
- Instant connection without additional setup
- Minimal disruption to workout flow
- Continuous pipeline: data collection → analysis → feedback
Solutions
S1. Machine-specific sensor-based measurement system
- Different sensing strategies were designed based on machine structure
- Pin-loaded machines: IR sensor (repetitions/velocity), ToF/LiDAR (weight)
- Plate-loaded machines: Load cell (weight), Gyroscope (motion)
- → Ensured accurate measurement across heterogeneous equipment
S2. Real-time data processing and feedback loop
- Data pipeline: Sensor → MCU (ESP32) → Bluetooth → Mobile App
- Real-time data streaming and processing during exercise
- Feedback on movement speed and repetition performance
- → Implemented an immediate measurement–analysis–feedback loop
S3. NFC-based frictionless interaction design
- NFC tag enables instant connection between device and smartphone
- One-tap interaction without manual setup
- Seamless onboarding between hardware and application
- → Minimized user effort and preserved workout flow
S4. Integrated user–trainer UX system
- User: Real-time coaching and performance feedback
- User: Automatic logging and visualization of workout data
- Trainer: Monitoring multiple users simultaneously
- Trainer: Providing data-driven personalized feedback
- → Established a connected ecosystem between personal training and expert coaching
Fig.1. Measurement device attached to a pin-loaded machine
Fig.2. Measurement device attached to a plate-loaded machine
Fig.3. System components: pin-loaded device, plate-loaded device, NFC-enabled smartphone dock, and mobile application
Fig.4. Internal design of the pin-loaded and plate-loaded devices with NFC-enabled dock
Results
R1. Sensor-based tracking system for strength training environments
- Implemented measurement strategies for both pin-loaded and plate-loaded machines
- Expanded tracking capability beyond cardio-focused systems
R2. End-to-end hardware–software prototype development
- Integrated sensor module, NFC docking system, and mobile application
- Achieved full pipeline: sensing → processing → communication → visualization
- Validated feasibility in real gym environments
R3. Enhanced user experience through real-time feedback
- Provided immediate feedback during exercise execution
- Improved movement consistency and performance quality
- Enabled independent workouts for beginners without trainer assistance
R4. Data-driven training and coaching workflow
- Automated workout logging and visualization
- Enabled user–trainer interaction through shared performance data
- Supported personalized coaching based on quantitative insights
Fig.5. Circuit design and hardware development process
Fig.6. Final prototype
Fig.7. Motion measurement process for the pin-loaded machine
Fig.8. Motion measurement process for the plate-loaded machine