A REPTILE EGG INCUBATOR WITH ARDUINO CO2 CONTROL THAT GREW LIVING MOUSE CELLS
A lab CO2 incubator is a serious purchase; this one starts from a cheap reptile egg incubator and adds Arduino-controlled CO2.
ScienceOpen-hardware
Built withArduino
- difficulty
- ●●●●○
- time
- a weekend-plus
- license
- GPL-3.0
- repo
- repo STABLE (NO COMMITS SINCE APRIL 2023)54 stars
●●●●○ · a weekend-plus · GPL-3.0 · 54 stars · repo STABLE (NO COMMITS SINCE APRIL 2023)
WHAT YOU’LL NEED
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COMPAREE VERDICT
This is a serious piece of lab equipment built honestly: rather than fabricating a heated chamber from scratch, it starts from a commercial reptile egg incubator (which already handles the heating) and adds closed-loop CO2 control. An Arduino reads an ExplorIR-M-20 infrared CO2 sensor and drives a 12V solenoid valve through a relay, slowly raising the CO2 level to about 5 percent, with a small OLED display and a door switch that cuts the CO2 when the door is open. The maker then grew real mouse fibroblast cells in it, which is the proof that matters in a build like this. The single thing most likely to go wrong is underestimating the cell culture side: you need sterile technique, growth media and access to cells, none of which this repository provides. The hardware is the easier half. The design is based on an earlier CO2 incubator tutorial by Andrew Pelling's lab at the University of Ottawa (credited in the video), whose own repository is licensed CC BY-NC-SA 4.0; the Thought Emporium code in this repository is GPL-3.0. If you are setting up a home or community biolab and already know how to handle cells, this is a genuinely useful build. If you are starting from zero on the biology side, the incubator is not your first problem.
IN THE REPO
GOOD TO KNOW
- —The repository contains a complete BOM, two circuit diagrams (breadboard and schematic), and working Arduino code.
- —No CAD files — the build starts from a commercially available reptile egg incubator, which already solves heating and insulation.
- —The design is based on an earlier CO2 incubator tutorial from Andrew Pelling's lab at the University of Ottawa (credited in the video); the Pelling Lab materials are licensed CC BY-NC-SA 4.0, which restricts commercial use of that material.
- —This repository's code is GPL-3.0; the Pelling Lab incubator it was based on is CC BY-NC-SA 4.0, so check both before any commercial use.
- —The repository itself is a parts list, two circuit diagrams and the code; the build walkthrough and the real mouse fibroblast cells growing inside are in the video 'This Machine Grows Living Flesh'.
- —You need access to mammalian cell lines, growth media, and basic sterile technique to use this as intended; the hardware build is only half the story.
Parts to buy
7 itemsFrom our check of the build. Exact quantities and part numbers are in the creator’s BOM.
Can I build this?
Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.
Videos
This Machine Grows Living Flesh
Full build and cell culture demo from The Thought Emporium
More builds like this
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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 full BOM in the repository and order the reptile incubator first — everything else waits on that arriving. (The BOM is in the main README.)
- 2.Source the ExplorIR-M-20 CO2 sensor early — it is the key part of the build and the one you will calibrate.(The repo lists it by its Digi-Key part number 2091-Explorir-M-20-ND.)
- 3.Watch the full video walkthrough to see the build sequence and the cell culture results. (The Thought Emporium shows the hardware assembly and the actual cells growing.)
- 4.Wire up the circuit on a breadboard first, following the diagrams in the repo, then upload the Arduino code and test with the OLED before committing to a permanent build.(The breadboard diagram is clearer than the schematic for a first pass.)
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
- The single biggest mistake is buying this thinking it solves cell culture end-to-end. It solves the incubator. You still need sterile technique, growth media, cell lines, and a laminar flow hood or equivalent — none of which are trivial or cheap. If you do not already have access to those, the incubator is not your first step.
- The ExplorIR-M-20 CO2 sensor is likely the priciest electronic part, and it needs calibrating: the repository includes a separate nitrogen calibration sketch and written calibration instructions. Do the calibration before trusting the readings.
- Two licences are in play: this repository's code is GPL-3.0, while the Pelling Lab incubator it was based on is CC BY-NC-SA 4.0 (non-commercial). If you want to sell units or a service, check what you reuse from each before you do.
- CO2 is heavier than air and an asphyxiant. If you are running this in a small room or poorly ventilated space, a leak or continuous vent can displace oxygen at floor level. Vent properly and do not run it in a bedroom or enclosed workspace.
- The reptile incubator is doing the temperature control, not the Arduino. If the base unit fails or its thermostat drifts, your cells die. Verify temperature stability with a separate thermometer before trusting it with a culture.
- The repository README does not mention the Pelling Lab incubator this design is based on; the link is in the build video's description (pellinglab.net/post/diy-incubator), and the Pelling Lab code is on GitHub at pellinglab/DIY-Incubator-Dec2014.
Can I use this without access to a lab?
The hardware build, yes. The cell culture part, no. You need sterile technique, growth media, and mammalian cell lines, which are not hobby-level. The incubator is for people who already know how to culture cells and want to do it outside a commercial lab.
What does the $$ cost band actually mean in money?
The creator does not publish a cost. The main purchases are a reptile egg incubator, the ExplorIR-M-20 CO2 sensor, a 12V solenoid valve, a relay, an Arduino and a small OLED, plus a CO2 cylinder and regulator. Check current prices for those parts before you commit.
Can I sell these?
The code in this repository is GPL-3.0. It was based on Andrew Pelling's DIY CO2 incubator tutorial, whose own materials are licensed CC BY-NC-SA 4.0 (non-commercial). If you plan to sell anything, check both licences and what you reuse from each before you do.
Do I need a CO2 tank, or can I generate it some other way?
You need a pressurised CO2 source and a regulator. Generating CO2 chemically or biologically will not give you the stable, controllable flow required for a closed-loop incubator. Budget for a small welding-grade or beverage-grade CO2 cylinder and a low-pressure regulator.
What cells did the maker actually grow in this?
Mouse fibroblasts: a primary cell line derived from adult mouse skin, shown growing in the video. They were chosen because they grow fast, are non-human and need no unusual growth media, which made them a good first test that the incubator holds conditions stable enough for mammalian cells.
Community builds
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Discussion1
FROM THE COMPAREE TEAM
The build video is called 'This Machine Grows Living Flesh' — growing cells is the only proof that matters for a CO2 incubator. If you were setting up a home or community biolab, what would you culture first?
The Thought Emporium
The Thought Emporium is a Canadian YouTube channel and independent lab focused on DIY biology, chemistry, and unconventional science projects. They built this incubator to enable mammalian cell culture outside of expensive institutional lab settings, then proved it works by growing real mouse fibroblast cells inside. The design builds on an earlier CO2 incubator from the Pelling Lab at the University of Ottawa, which they credit.
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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: the repository is small but has the essentials — an electronics parts list, two circuit diagrams, the main Arduino code, and a separate nitrogen calibration sketch with written calibration instructions. The README itself is brief and points to the build video, so expect to follow The Thought Emporium's 'This Machine Grows Living Flesh' alongside the code. The code is GPL-3.0, and the repository has not been updated since April 2023. The parts list is all about CO2 control — the ExplorIR-M-20 sensor, a solenoid valve and the relay that drives it — and you will also need a CO2 supply to feed it. If you are already handling cell cultures and just need a cheaper incubator, this is a solid starting point. If you are starting from zero on the biology side, the hardware is not your first problem. 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.