YOU CAN BUILD A LAB MACHINE THAT MOVES DROPLETS AROUND LIKE A VIDEO GAME
A desktop machine that walks droplets around a grid with voltage alone — no pumps, no tubes, just electrodes and physics.
ScienceOpen-hardware
- difficulty
- ●●●●○
- time
- a weekend-plus
- license
- GPL-3.0
- repo
- repo ACTIVE483 stars
●●●●○ · a weekend-plus · GPL-3.0 · 483 stars · repo ACTIVE
WHAT YOU’LL NEED
- 3D printer + filament — printable parts — files are in the repo
- Electronic parts — full list with part numbers in the repo BOM
- Dev board / microcontroller — runs the project firmware
Partner
COMPAREE VERDICT
OpenDrop is a serious lab instrument project for people who already solder electronics and want to explore digital microfluidics — the technique that moves tiny droplets around a flat grid using voltage gradients instead of pumps. The physics is elegant: electrodes under a hydrophobic surface pull drops from square to square, so you can program liquid handling like a chess game. The repository includes everything to build the control board and the cartridge that holds the droplets, and the firmware is a working Python stack. The hard part is not the electronics — it is the droplet handling itself. Getting reliable movement depends on surface prep, reagent properties, and voltage tuning, and the docs do not walk you through that troubleshooting. This is a tool for the DIY biology community, not a kit for your first weekend build. The single biggest trap is expecting plug-and-play: you will need to experiment with coatings, droplet volumes, and software parameters before drops reliably obey. If you have lab access or a strong background in chemistry or biotech, this is a rare open-hardware path into a technology that is otherwise locked behind expensive commercial platforms. If you are new to both electronics and lab work, start with something simpler and come back.
IN THE REPO
NOT IN THE REPO
- —Full PCB design files, firmware, and mechanical CAD present in the repository under GPL-3.0.
- —The BOM lists components but not suppliers; some specialised parts (high-voltage driver ICs, hydrophobic coating) are not off-the-shelf.
- —Assembly instructions exist but assume intermediate electronics skills — there is no beginner walkthrough.
- —The cartridge design is included; fabricating the hydrophobic surface requires lab access or experimentation.
- —GaudiLabs sells assembled units; the open hardware release is for people who want to build or modify.
- —GPL-3.0 licence permits commercial use with source release.
Can I build this?
Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.
Partner · KickstarterHeyGears G1: 10M+ colors and transparent parts in one print, plus UV printing on flat objects. Figures, parts and labels — no painting.
Gallery
Start here
Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.
- 1.Read the repository README and the assembly guide in /docs to understand the full scope before buying parts (The BOM and build instructions are there; start by confirming you can source the high-voltage ICs and coating material)
- 2.Order the PCB — Gerber files are in /hardware/electronics(Any fab house that handles two-layer boards will work; JLCPCB and PCBWay are common choices)
- 3.Source components per the BOM; pay attention to the high-voltage driver and hydrophobic coating(Some components are specialised; plan for international shipping or substitutions)
- 4.Assemble the control board and test the firmware on an Arduino Due before building the cartridge(Firmware is Python-based; testing the electrical side first avoids mixing electrical and chemical troubleshooting later)
KNOWN ISSUES
- The hydrophobic coating is the hardest part to get right — Teflon AF is expensive and requires careful application in a ventilated space. Some builders substitute with commercial hydrophobic sprays; results vary.
- Droplet movement is sensitive to surface cleanliness, reagent viscosity, and voltage tuning. The docs explain the principle but not the iterative debugging — expect trial and error.
- The high-voltage driver ICs may not be in stock at common distributors; check lead times before committing to a build timeline.
- The repository does not include a beginner-friendly assembly video or step-by-step photo guide — you are working from schematics and text instructions.
- If you have never worked with lab reagents or surface chemistry, the cartridge fabrication will be steeper than the electronics.
- GaudiLabs sells assembled units; if you are building purely to save money rather than to modify or learn, compare the cost of parts plus your time.
What can I actually do with this once it is built?
Move, mix, and split microliter-scale droplets for experiments in chemistry, biology, or materials science. Common uses include mixing reagents, running enzymatic assays, or exploring new protocols without pipettes. It is a research tool, not a consumer product.
Do I need a biology or chemistry background to use it?
Not strictly, but you will get more out of it if you do. The machine handles droplets; what you do with them depends on your experimental goals. Without a lab context, it is a fascinating physics demo but not a daily-use device.
Can I buy a pre-assembled unit instead of building?
Yes — GaudiLabs sells assembled OpenDrop units. The open hardware release is for people who want to modify the design, save cost, or integrate it into other systems.
How does this compare to commercial digital microfluidics platforms?
Commercial platforms cost thousands to tens of thousands and come with support, certified protocols, and regulatory compliance. OpenDrop trades those for open access, customisability, and a build cost under $300. It is aimed at researchers, educators, and DIY bio labs, not regulated diagnostics.
What is the hardest part of the build?
Getting reliable droplet motion. The electronics usually work on the first try if you follow the BOM and schematics. The surface coating, droplet composition, and voltage settings require iteration and are not fully documented for every reagent type.
Community builds
No community builds yet — be the first, we feature the best ones.
Discussion1
FROM THE COMPAREE TEAM
The hardest part is not the electronics — it is tuning the surface and reagents until drops reliably move. What would you experiment with first: reagent chemistry, coating technique, or voltage profiles?
Urs Gaudenz / GaudiLabs
Urs Gaudenz runs GaudiLabs, a Swiss open hardware lab focused on accessible scientific instruments for the DIY biology and maker communities. OpenDrop grew from the hackteria network and years of work on personal lab automation, following the same open-source philosophy as GaudiLabs' earlier PocketPCR thermocycler.
Keep building — related projects
Same category, picked by how close they are to this build.
FULL CADOne homemade board that can listen to almost every radio signal in the air around you
Open-hardwareScience●●●●○advanced
FULL CADA lab positioning stage costs 10,000 dollars. This one steps 50 nanometers and is open source
ScienceOpen-hardware●●●●●expert
Partner · KickstarterCodeeBot: build the robot from Lego-compatible bricks and program it by hand; a GPT tutor explains each step.
FULL CADAllsky: a Raspberry Pi camera in a weatherproof dome that films the whole night sky by itself
ScienceOpen-hardware●●●○○moderate
NO CAD FILESTinyGS — open source global satellite ground station network
Open-hardwareScience●●○○○starter
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.
CompareeTEAM11d ago
Practical notes from our verification: the repository is actively maintained under the GaudiLabs organisation, and the hardware files are complete — PCB Gerbers, BOM, and firmware all present. There is no official walkthrough video; the best documentation is in the /docs folder and the README. The single biggest unknown before you start is sourcing the hydrophobic coating — Teflon AF works but is expensive and requires lab ventilation; some builders report success with commercial superhydrophobic sprays, but that path is not documented in the repo. If you have built electronics kits before but never worked with surface chemistry, budget extra time for the cartridge side.