Smart Steering Wheel Sensor System

A low-cost experimental smart steering wheel interface that detects driver steering angle and hand-grip position using simple analog and capacitive sensors. The project demonstrates an early prototype for driver alertness and ergonomics monitoring, forming the foundation for future HRV-based fatigue sensing integration.

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Overview

This system measures:

• Steering angle via a potentiometer connected to the steering shaft
• Left and right hand grip using DIY foil-based capacitive touch sensors
• (Planned) Heart-Rate Variability (HRV) sensing for stress and fatigue estimation

Data is streamed over the serial interface for visualization in the Arduino Serial Plotter or for CSV logging.

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Features

• Continuous analog measurement of steering angle
• Capacitive sensing for driver hand presence at 3 o’clock and 9 o’clock positions
• Automatic baseline calibration on startup
• Noise filtering and adaptive thresholding
• Serial output formatted for real-time visualization

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Hardware Setup

Component	Function	Arduino Pin
Potentiometer	Steering angle sensor	A0
(Future) HRV / Heart sensor	Reserved	A1
Left foil touch pad	Grip detection (left hand)	A2
Right foil touch pad	Grip detection (right hand)	A3

Additional Components

• Arduino Uno (or compatible board)
• 10kΩ Potentiometer (for steering)
• Aluminum foil pads + wires (for touch sensors)
• Optional: Breadboard + jumper wires

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Circuit Diagram

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Prototype Setup

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How It Works

1. Baseline Calibration

   • At startup, the system samples each touch pad multiple times to establish a no-touch baseline.

2. Capacitance Reading

   • Each foil is charged for a few microseconds and then switched to input mode.
   • The analog read value correlates to capacitance (and thus proximity or touch).

3. Touch Detection

   • If the measured value exceeds the baseline by more than a relative or absolute threshold, the system registers a “touch”.

4. Steering Measurement

   • The potentiometer gives steering displacement around center (512) mapped from 0–1023.

5. Data Logging

   • The serial output includes:

     steerDisp	rawL	rawR	normL	normR	touchL	touchR
     

   • Ideal for monitoring in Serial Plotter or saving to CSV for post-processing.

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📊 Example Serial Output

steerDisp	rawL	rawR	normL	normR	touchL	touchR
-24	        105	107	0.013	0.018	0	0
32	        189	124	0.278	0.035	1	0
45	        195	201	0.289	0.294	1	1

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Future Improvements

• Integrate HRV sensor (A1) for physiological monitoring
• Add haptic or LED feedback on grip loss or drowsiness events
• Fuse steering angle + HRV + grip patterns for real-time fatigue scoring
• Log and visualize over time using Python / Processing dashboard

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