DOI: 10.5061/dryad.63xsj3vd9
title: Towards human-resolution haptics: A high bandwidth, high density, wearable tactile display

description: Despite advances in digitizing vision and hearing, touch still lacks an
 equivalent digital interface matching the fidelity of human perception.
 This gap limits the quality of digital tactile information and the realism
 of virtual experiences. Here, we introduce a step towards human-resolution
 haptics: a class of wearable tactile displays designed to match the
 spatial and temporal acuity of the human fingertip. Our device, VoxeLite,
 is a 0.1 mm-thick, 0.19 g, skin-conformal array of individually
 addressable soft electroadhesive actuators (“nodes”). As users touch and
 move across surfaces, VoxeLite deliver high-resolution distributed forces
 via the nodes. Enabled by scalable microfabrication techniques, the
 display achieves actuator densities up to 110 nodes/cm², produces stimuli
 up to 800 Hz and remains transparent to real-world tactile input. We
 demonstrate its ability to render small-scale hapticons, virtual textures,
 and transmit physical surfaces, validated through human psychophysics and
 biomimetic sensing. These findings position VoxeLite as a platform for
 human-resolution haptics in immersive interfaces, robotics, and digital
 touch communication.
description: # Towards human-resolution haptics: A high bandwidth, high density,
 wearable tactile display Dataset DOI:
 [10.5061/dryad.63xsj3vd9](10.5061/dryad.63xsj3vd9) ## Description of the
 data and file structure All data files are in matlab (.mat) format. ##
 File: characterization.zip **Description:** This folder contains all the
 data used in characterizing different versions of VoxeLite. Each data set
 contains the recorded bulk finger velocity (obtained from a Laser Doppler
 Vibrometer) and the lateral force response (obtained from a force sensor)
 of VoxeLite. #### File naming Each file contains data for one version of
 VoxeLite. The parameters of VoxeLite that were changed are:  *
 concentration of carbon nanotube additives: indicated by
 "cLatex_*x*", where *x* is either "0.5",
 "1.0", "1.5", or "2.0". If no indication is
 made, "1.0" was used.  * 0.5 = 0.83 wt% CN * 1.0 = 1.65 wt% CN *
 1.5 = 2.48 wt% CN * 2.0 = 4.1 wt% CN * shore hardness of the node:
 indicated by "20A", "40A", or "60A". If no
 indication is made, "40A" was used. ### File: optimization
 **Description:** This folder contain all data used in optimizing the
 electrical and mechanical properties of VoxeLite. Naming convention of
 files are: "calibration_cLatex-*concentration of carbon
 nanotubes-actuation frequency-shore hardness (40A if not
 indicated)*-combined" e.g.
 "calibration_cLatex-1.5-100Hz-20A-combined.mat": VoxeLite that
 has 2.48 wt% CN, actuated at 100 Hz, and has a shore hardness of 20A. ####
 File content Each file contains a struct that contains all the test data
 for a given version of VoxeLite, based on the file name. Each struct
 contains 8 variables:  * **DAQ**: data collected from the DAQ * **Time**:
 timestamps for the data collected, in seconds * **Dev1_ai8**: LDV data, in
 V * **Dev1_ai7**: Lateral Force data, in V * **Fs**: DAQ sampling rate for
 a given test run * **voltage**: actuation voltage for a given test run, in
 V * **device**: device number for a given test run. 3 different devices
 are tested for each version of VoxeLite.  * **frequecy**: actuation
 frequency for a given test run, in Hz * **velocityScale**: LDV scale to
 convert from V to mm/s ### File: spatiotemporal **Description:** This
 folder contain all data used in characterisng the spatiotemporal response
 of VoxeLite. A single version of the device was used (1.65 wt% CN, 40A).
 The charactersation includes: * A frequency sweep from 2 - 77 Hz, at 5
 actuation voltages: * files labeled "freq-cLatex-1.0-40A-*actuation
 voltage*.mat" * A voltage sweep from 60 - 200V, at  with actaution
 frequecies of 100 - 250 Hz: * files labeled:
 "voltage-cLatex-1.0-40A-*actuation frequency*.mat" #### File
 content Each file contains a struct that contains all the test data for a
 given version of VoxeLite, based on the file name. Each struct contains 8
 variables:  * **DAQ**: data collected from the DAQ * **Time**: timestamps
 for the data collected, in seconds * **Dev1_ai8**: LDV data, in V *
 **Dev1_ai7**: Lateral Force data, in V * **Dev1_ai14**: scaled input
 voltage, in V * **Fs**: DAQ sampling rate for a given test run *
 **voltage**: actuation voltage for a given test run, in V * **frequecy**:
 actuation frequency for a given test run, in Hz * **velocityScale**: LDV
 scale to convert from V to mm/s ### File: transparency
 **Description:** This folder contain all data used in characterisng the
 haptic transparency of the device when interacting with 8 different
 textures. 3 conditions were used:  1. **bare:** "bare finger
 condition" where sensor was left bare 2. **device:** VoxeLite was
 attached to the sesnor similarly to how it is attached to a real finger 3.
 **latex:** a 0.5mm thick of latex is attached to the sensor 8 textures
 were used:  1. **Bedding 1:** polyester bedding  2. **Bedding 2:** cotton
 bedding  3. **Corduroy 9 wale** 4. **Corduroy 14 wale**  5. **leather
 green:** full grain leather  6. **leather grey:** faux leather 7. **towel
 1:** microfiber towel 8. **towel 2:** terrycloth towel #### File content
 Each file contains 2 variables:  * **SEP:** mean pixel value data from 29
 2x2 mm blocks selected from the recorded sensor video, across 900 frames *
 **str:** name of file ## File: demo.zip **Description:** This folder
 contain all subect responses from the haptic demonstrations. Three
 demonstrations were performed:  1. **"direction":** identifying
 hapticon (active state).Responses are located in files named 
 "direction_S*x*", where *x* is the subject number.  2.
 **"texture"**: identifying textures (active state). Responses
 are located in files named "textureTest_S*x*", where *x* is the
 subject number  3. **"matching":** matching real textures in
 bare finger, latex (plain_thick), or VoxeLite (6x6) condition. Responses
 are located in files named "matching_*Sx*_*condition*", where
 *x* is the subject number, and *condition* is one of the above mentioned
 conditions.  #### File content Each file contains a struct that contains
 all the test data for a given subject. Each struct contains 3 variables: 
 * **trialNum:** test trial number * for direction test (direction_S*x*.m
 files) * **dirSent:** direction number presented to subject  * **ans**:
 answer number answer provided by subject  * for texture test
 (textureTest_S*x*.m files) * **textureSim:** texture number presented to
 subject  * **textureAns**: texture number answer provided by subject  *
 for matching test (matching_*Sx*_*condition*.m files) * **order**: texture
 number that was presented  * **AnsName**: answer provided by subject ##
 Code/software MatLab 2022b was used to visualize the experimental data.
 The file name of Matlab code includes the Figure number and a short
 description of it. * **"conductivityPlot.m":** This Matlab
 script calculates and plots a comparison graph of VoxeLite with different
 conductivities. The script read data from
 "calibration_cLatex-*x*-100Hz-combined.m". *
 **"modulusPlot.m":** This Matlab script calculates and plots a
 comparison graph of VoxeLite with different moduli. The script read data
 from "calibration_cLatex-1.5-100Hz-20A-combined.m",
 "calibration_cLatex-1.5-100Hz-combined.m", and
 "calibration_cLatex-1.5-100Hz-60A-combined.m". *
 **"frequencySweep.m":** This Matlab script calculates and plots
 a comparison graph of VoxeLite actuated at different frequencies. The
 script read data from "freq-cLatex-1.0-40A-*x*.m" *
 **"voltageSweep.m":** This Matlab script calculates and plots a
 comparison graph of VoxeLite actuated at different voltages. The script
 read data from "voltage-cLatex-1.0-40A-x" *
 **"gaborfiltering.m":** This Matlab script calculates and plots
 the Spatial Event plots obtained with the sensor. The script read data
 from the "transparency" folder.  * **"demos.m"** This
 Matlab script calculates and plots the results from the haptic
 demonstration. The script read data from the "demo" folder.  ##
 Human subjects data All study procedures were approved by the Northwestern
 University Institutional Review Board. Participants provided explicit
 informed consent for the public release of de-identified data. To ensure
 anonymity, all direct identifiers (e.g., names, contact information, and
 other personally identifying details) were removed from the dataset. Each
 participant was assigned a random numeric code unrelated to their
 identity, and no indirect identifiers that could reasonably be used to
 re-identify individuals were retained.