THE ENACTIVE TORCH: AN OPEN-SOURCE DEVICE THAT TURNS DISTANCE INTO TOUCH
Point this at a wall and it buzzes fast; point it down a corridor and the buzz drops low — a handheld device that converts measured distance into vibration you feel.
by Embodied Cognitive Science Unit, Okinawa Institute of Science and Technology
ScienceOpen-hardware
Built withArduinoTeensy3D printing
- difficulty
- ●●●●○
- time
- a weekend-plus
- license
- CC-BY-4.0
- repo
- repo FINISHED0 stars
●●●●○ · a weekend-plus · CC-BY-4.0 · 0 stars · repo FINISHED
WHAT YOU’LL NEED
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COMPAREE VERDICT
The Enactive Torch is a research-grade sensory substitution device from OIST's Embodied Cognitive Science Unit: a handheld torch whose TFMini-S micro LiDAR measures distance and turns it into vibration, either in your palm or through an external actuator module you can place anywhere on the body. Vibration frequency falls linearly from 145 Hz at 4 cm to 60 Hz at 750 cm. It runs on a Teensy 4.0 with sine-wave generators and audio amplifiers driving linear resonant actuators, logs distance, motion and settings to a microSD card, and sends triggers for EEG synchronisation. The OSF repository has the PCB design and manufacturing files (Gerber, BOM, CPL), the case files, step-by-step instruction PDFs and working firmware, all CC BY. The paper puts the hardware cost at about 500 US dollars. It is a lab instrument, not a certified assistive device.
IN THE REPO
GOOD TO KNOW
- —PCB design and manufacturing files (Gerber, BOM, CPL), 3D-printed enclosure STLs, wiring diagrams, step-by-step instruction PDFs and Teensy 4.0 firmware are on OSF, alongside the HardwareX paper.
- —The licence is Creative Commons Attribution (CC BY 4.0) — commercial use is permitted with attribution.
- —Hardware cost is approximately 500 US dollars as stated in the paper; in the BOM the actuators, connector cable, LiDAR and LiPo charger/boosters are the largest items.
- —This is a research instrument published by a neuroscience lab, not a consumer assistive device — it logs and synchronises data for experiments.
- —No official support channel exists; the paper is the documentation and the OSF page is the repository.
Parts to buy
11 itemsFrom our check of the build. Exact quantities and part numbers are in the creator’s BOM.
- Teensy 4.0Find
- TFMini-S micro LiDARFind
- Two vibration motors (internal + external module)Find
- Two Class D audio amplifiersFind
- Two AD9833 wave generatorsFind
- Digital potentiometersFind
- LiPo charger/boosters and batteryFind
- 9-DoF IMUFind
- MicroSD adapterFind
- Laser pointerFind
- Custom PCB (Gerbers on OSF)from the repo files
Can I build this?
Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.
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Start here
Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.
- 1.Read the HardwareX paper (The open-access HardwareX paper is the complete build guide: BOM, assembly, firmware, operating modes and validation. The OSF repository holds the files it refers to.)
- 2.Order the PCB (Download the Gerber, BOM and CPL files from the "Circuit Board Manufacturing Files" folder on OSF and send them to JLCPCB or another board house; the "ET Online Printed Circuit Board (PCB)" PDF walks through the JLCPCB order step by step.)
- 3.Source the components (The full BOM is ET BOM.pdf in the OSF Instructions folder. The Teensy 4.0, TFMini-S LiDAR and the Alps Alpine AFT14A903A actuators are the critical parts — verify stock before ordering.)
- 4.Print the enclosure (STL files are on OSF. The team orders them from an online 3D printing service (SLS nylon body, SLA resin window) — the "ET Online 3D Printing" PDF walks through it.)
Resources
Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.
KNOWN ISSUES
- Check stock of the TFMini-S micro LiDAR (SparkFun SEN-16977) before ordering the rest of the BOM — the firmware is written for it, so a different sensor means adapting the code.
- Two digital potentiometers (MCP4151) are surface-mount; everything else is modules and through-hole parts. If you have only done through-hole work, practise the two SMD chips first or use flux and a fine tip.
- The Teensy 4.0 firmware reads the LiDAR on a hardware serial port, talks to the host over USB serial and logs to the microSD card; if you have never worked with hardware serial on Teensy, try the Arduino IDE examples first.
- Both actuators are the same Alps Alpine AFT14A903A model; the BOM recommends buying a third as a spare in case one is damaged during assembly.
- The external actuator module can go anywhere on the body; the BOM uses double-sided Velcro on its printed case, so plan how you will keep it from shifting during a session.
- This is a research instrument that logs data and synchronises with external systems — if you only want the distance-to-vibration function and do not need the logging, you can simplify the firmware, but the paper does not document that path.
Can I use this as an actual assistive device?
No. This is a research prototype published for neurophysiological experiments, not a certified assistive or medical device. It has no safety approvals, no user testing for daily use, and no support infrastructure. If you want to explore sensory substitution for yourself or in a lab, it is a solid starting point.
What LiDAR sensor does it use?
A TFMini-S micro LiDAR module (SparkFun SEN-16977) with a 0.1-12 m range, read over a hardware serial port on the Teensy. Swapping it for another sensor means adapting the firmware to the new sensor's protocol.
Do I need to order the custom PCB or can I breadboard this?
You can breadboard a proof-of-concept, but the paper's build uses the custom PCB, and the OSF repository provides the Gerber, BOM and CPL files so a board house such as JLCPCB can make (and partly assemble) it.
How loud are the actuators?
The paper does not measure loudness. It drives the Alps Alpine AFT14A903A linear resonant actuators only between 60 and 145 Hz, deliberately below their resonant frequencies, to reduce extraneous noise.
Is it battery-powered?
Yes. It runs from two separate 3.7 V, 1000 mAh LiPo batteries, each with its own LiPo charger/booster module that provides a stable 5 V output, and an LED visible through the transparent side window shows charging status.
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Discussion1
FROM THE COMPAREE TEAM
Hardware cost is about 500 dollars, and the torch turns distance from a TFMini-S LiDAR into vibration you feel in your hand. What would you use a device like this for: research, accessibility, or just to feel the world differently?
Embodied Cognitive Science Unit, Okinawa Institute of Science and Technology
The Enactive Torch was developed by Stephen Estelle, Lohith Dayantri, Ziwen Meng, Brian Morrissey and Tom Froese at OIST's Embodied Cognitive Science Unit, which studies how perception and action are coupled in biological and artificial systems. The updated device was published in HardwareX so other labs could replicate and extend the work.
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DISCLAIMER
- Comparee is not the author of the projects featured here. All rights to each project belong to its creator — every page links to the original source, and we never host creators’ files.
- Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
- Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
CompareeTEAM1mo agoedited
Practical notes from our verification: this is a thoroughly documented sensory substitution device: the open-access HardwareX paper walks through the design decisions and the build step by step, and the OSF repository holds the CAD files, the PCB design together with Gerber, BOM and placement files for ordering an assembled board, and the firmware. The device runs on a Teensy 4.0, measures distance with a TFMini-S micro LiDAR (0.1 to 12 m), drives its haptic feedback through two AD9833 signal generators and two Class D audio amplifiers, and is powered by a LiPo battery through charger/booster modules. Most of the soldering is through-hole, but two digital potentiometers are surface-mount, so bring a fine tip and some flux. Programming the Teensy through the Arduino IDE is part of the build. If you have built a board-level device before, the paper gives you what you need. Correction (4 October 2026): we re-checked this page line by line against the project's own repository, documentation and videos, and fixed errors in earlier versions.