Wearable Photoelectric Fingertip Force Sensing System Based on Blood Volume Changes without Sensory Interference
Kangkang Dong1, Yao Chu2,3, Xuanchen Tian1
1Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
ACS Applied Materials & Interfaces
|July 13, 2023
Summary
A new wearable photoelectric fingertip force sensing system (PFFS) measures fingertip force by detecting blood volume changes. This non-invasive method digitizes craftsman skills, like Traditional Chinese Medicine pulse diagnosis, without affecting natural touch.
Area of Science:
- Biomedical Engineering
- Sensory Systems
- Wearable Technology
Background:
- Accurate fingertip force monitoring is vital for digitizing skilled craft.
- Existing force sensors disrupt natural tactile sensation.
- Traditional Chinese Medicine (TCM) pulse diagnosis requires precise fingertip force measurement.
Purpose of the Study:
- To develop a non-invasive fingertip force sensing method.
- To design a wearable system for digitizing TCM pulse diagnosis.
- To overcome limitations of conventional force sensors.
Main Methods:
- Developed a photoelectric fingertip force sensing system (PFFS).
- Utilized photoelectric plethysmography to detect blood volume changes in the fingertip.
- Investigated effects of light wavelengths, temperature, and heartbeat artifacts on sensor output.
Main Results:
- PFFS successfully detects fingertip force by correlating blood volume changes with output current.
- Established a relationship between blood volume changes and fingertip force using experimental and theoretical approaches.
- Demonstrated PFFS feasibility for TCM pulse diagnosis without sensory interference.
Conclusions:
- The PFFS enables non-invasive digitalization of fingertip forces during TCM pulse diagnosis.
- The system shows potential for object viscosity perception and gesture recognition.
- This technology advances the digitization of natural fingertip force sensing.


