CoinFT: A Coin-Sized, Capacitive 6-Axis Force Torque Sensor for Robotic Applications
Abstract
We introduce CoinFT, a capacitive 6-axis force/torque (F/T) sensor that is compact, light, low-cost, and robust with an average root-mean-squared error of 0.16N for force and 1.08mNm for moment when the input ranges from 0~14N and 0~5N in normal and shear directions, respectively. CoinFT is a stack of two rigid PCBs with comb-shaped electrodes connected by an array of silicone rubber pillars. The microcontroller interrogates the electrodes in different subsets in order to enhance sensitivity for measuring 6-axis F/T. The combination of features of CoinFT enables various contact-rich robot interactions across different embodiment domains including drones, robot end-effectors, and wearable haptic devices. We demonstrate the utility of CoinFT through two representative applications: a multi-axial contact-probing experiment in which a CoinFT mounted beneath a hemispherical fingertip measures 6-axes of force and torque representative of manipulation scenarios, and an attitude-based force-control task on a drone. The design, fabrication, and firmware of CoinFT are open-sourced at https://coin-ft.github.io/.
Cite
@article{arxiv.2503.19225,
title = {CoinFT: A Coin-Sized, Capacitive 6-Axis Force Torque Sensor for Robotic Applications},
author = {Hojung Choi and Jun En Low and Tae Myung Huh and Seongheon Hong and Gabriela A. Uribe and Kenneth A. W. Hoffmann and Julia Di and Tony G. Chen and Andrew A. Stanley and Mark R. Cutkosky},
journal= {arXiv preprint arXiv:2503.19225},
year = {2026}
}