YOU CAN BUILD THE 2,500-DOLLAR DRONE WINCH FOR 120 DOLLARS, AND IT LIFTS 3 KG
A drone winch that holds 27 metres of line, lifts 3 kg, and costs 120 dollars in parts instead of 2500.
by William Crowe, Benicio Costales, Kyle Luthy
RoboticsOpen-hardware
Built withArduino3D printing
- difficulty
- ●●●●○
- time
- a weekend-plus
- license
- CERN-OHL-S-2.0
- repo
- repo FINISHED0 stars
●●●●○ · a weekend-plus · CERN-OHL-S-2.0 · 0 stars · repo FINISHED
WHAT YOU’LL NEED
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COMPAREE VERDICT
CLARK-3 is an open-hardware winch designed to lower and raise payloads from a multirotor without landing — water samples, sensors, delivery drops. The commercial winches that do this cost on the order of 2500 dollars where prices are published. This one costs about 120 dollars in parts and weighs 0.8 kg. It holds 27 metres of 130 N monofilament, lifts 3 kg, and can report line length over MavLink so the pilot knows how much line is out. Most of it is 3D-printed, so a broken gear is reprinted in the field rather than shipped. The paper is honest about what it is not: the 3 kg limit is a motor torque limit, not a material one, so a different gear ratio could push it past 10 kg. The single biggest trap is regulatory, not technical — flying with a suspended load is restricted in most places, and a university research exemption is not the same as permission to fly this over a park. The build itself is intermediate: you are printing gears, assembling a gearbox, wiring an Arduino, and integrating it with a flight controller that speaks PWM and MavLink. If you have done that before, this is a weekend-plus. If you have not, it is a longer learning curve. The files are complete, the hardware licence (CERN-OHL-S) lets you modify it as long as you share your changes under the same licence, and the design is field-repairable. It is a real alternative to a commercial winch if you can legally fly it.
IN THE REPO
GOOD TO KNOW
- —Published in HardwareX with full CAD files, bill of materials, Arduino code and assembly instructions on Mendeley Data.
- —Hardware under CERN-OHL-S v2 (reciprocal open-hardware licence), software under LGPL, paper under CC BY 4.0.
- —Most parts are 3D-printed PLA and resin. Standard fasteners and a continuous servo from Amazon make up the rest.
- —MavLink integration is included so the pilot sees line length in the ground station.
- —The paper is single-source verification — the authors tested it, but this is not a production drone part with independent field data.
- —Flying with a suspended load is regulated in most jurisdictions. Check local rules before you fly it.
Parts to buy
10 itemsFrom our check of the build. Exact quantities and part numbers are in the creator’s BOM.
- Continuous rotation servo (25 kg*cm)Find
- Arduino Pro Mini 3.3 VFind
- Control and interface PCB (Gerbers in the dataset)from the repo files
- 7.5 V step-down regulatorFind
- Hall effect sensor and magnetFind
- Limit switchFind
- Bearings and a 6 mm linear shaftFind
- Heat-set inserts and metric fastenersFind
- 130 N monofilamentFind
- Flight controller with a spare PWM outputFind
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 paper has the full assembly sequence, bill of materials with supplier links, and the MavLink integration notes.)
- 2.Download the CAD files and Arduino code from Mendeley Data(The paper links to Mendeley Data (DOI 10.17632/pd67rx3k5y.1), where the STEP files, Arduino code, PCB files with Gerbers and the assembly video are hosted. Export the STEP parts to STL for printing.)
- 3.Order the continuous rotation servo and Arduino Pro Mini(The BOM specifies models. Amazon links are in the paper. Do not substitute the servo without checking torque specs.)
- 4.Print the main body and gears in PLA, and the level-wind diamond screw in resin(The paper prints the gears and traveler parts at 0.1 mm layer height and everything else at 0.16 mm. Test-fit the gearbox before final assembly.)
KNOWN ISSUES
- The biggest mistake happens before you build: flying with a suspended load is restricted in most jurisdictions. A university research exemption is not the same as permission to fly this. Check local rules.
- The 3 kg payload rating is a motor torque limit, not a structural one. Do not assume you can just load it to 3 kg without testing — the paper tested it, you have not.
- MavLink integration requires a flight controller that speaks it and a ground station that can display custom telemetry. If your controller does not support MavLink, you lose the line-length readout.
- Gear alignment is fussy. Print a test gearbox before you assemble the full winch — a badly aligned gear will bind or strip under load.
- The line spec matters. The 27 m capacity and the load tests in the paper are for 130 N monofilament; a different line changes how much fits on the spool and what load it can safely carry.
- The paper does not cover how to legally certify this for commercial use. If you are planning paid delivery flights, this is a research prototype, not a certified system.
Can I scale this to lift more than 3 kg?
The paper says the 3 kg limit is a motor torque limit, not a material one. Change the gear ratio and the same winch could theoretically lift over 10 kg. You would need to test that yourself — the paper did not.
Do I need a resin printer, or can I print everything in PLA?
In the paper only one part, the level-wind diamond screw, is printed in resin (on a Formlabs Form 3 at 0.05 mm layers); everything else is FDM PLA. Printing that screw in PLA is untested by the authors, so expect to experiment, or have it printed by a resin service.
What flight controllers work with this?
Most flight controllers that can deliver a PWM output to a custom device will work; MavLink support is what gives you the line-length readout. Pixhawk and ArduPilot-based boards are the obvious choices. The paper used a Pixhawk 2.
Can I fly this commercially?
Not without certification. This is a research prototype published under an open-hardware licence. Commercial drone operations have regulatory requirements that this does not meet out of the box.
What is the actual cost?
The paper says 75 to 120 dollars depending on what you already have. In its bill of materials the servo, the control PCB and the step-down regulator are each about 25 dollars, the Arduino Pro Mini about 11, and bearings, fasteners, sensor and filament make up the rest. One part (the diamond screw) is printed in resin; the paper notes the filament and resin are sold in quantities that cover several builds, so a resin bottle is an extra up-front cost if you do not already have one. If you are buying everything, plan for 120 plus materials.
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Discussion1
FROM THE COMPAREE TEAM
The paper says the 3 kg limit is just the motor — change the gear ratio and it could lift 10 kg. Would you build it as-is, or would you go straight for the heavier-lift version?
William Crowe, Benicio Costales, Kyle Luthy
William Crowe, Benicio Costales and Kyle Luthy are researchers at Wake Forest University. They built CLARK-3 because the existing drone winches cost more than 2500 dollars, are proprietary, and cannot be repaired in the field. They published it in HardwareX so anyone with a 3D printer could build one.
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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.
CompareeTEAM22d agoedited
We verified this from the open-access HardwareX paper. The design files, Arduino code, PCB files and an instructional assembly video (Winch_Assembly_Video_1.mp4) are in the authors' Mendeley Data repository (DOI 10.17632/pd67rx3k5y.1). Testing is single-source: the Wake Forest team bench-tested it and field-tested it for water sampling at Lake Katharine in Winston-Salem, and there is no independent field data yet. The winch is driven by a standard PWM signal, so most flight controllers with a spare PWM output can run it; the authors used a Pixhawk 2, and the optional MavLink link reports line length back to the ground station. The paper does not cover regulations: flying with a suspended load is restricted in many places, and this is not a certified system. For research or hobby flights with permission, the design is complete. For commercial delivery, treat it as a starting point, not a ready-to-fly product. 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.