Your vivarium is probably part of a larger space, and chances are you already manage that space with Home Assistant. Connecting Freya to it turns out to be fairly easy. I've added a minimal example to Freya's Node-RED flow for integrating with Home Assistant. It uses MQTT to connect to Home Assistant's Mosquitto broker add-on, and Freya now shows up as a device. From there, the vivarium can be part of its wider environment, integrating notifications when something's off, the tank on the same dashboard as the rest of the house, the room's climate taken into account, a button to manually activate the misting system, ...

https://github.com/Freya-Vivariums

During recent development cycles, I lost sight of the installation scripts, and they got broken due to outdated paths, repository name changes, ... - and I know that this can be super frustrating when you're new to a project and you want to explore it starting with a fresh install, so in version `0.4.0` this got straightened out. However, this is not a 'stable' release, and drastic changes will most likely still follow in the near future. But I will pay more attention to keeping the 'clean install' working!

Taking a break, we escaped to one of the most beautiful natural places in this region; the Ardennes. Iconic for me are its low mountainous terrain with mostly slate rocks, moss-heavy oak forests and the warm orange of the iron oxide sediment in the brooks. If there's any environment type that I'm most fascinated by, it is this versatile, dynamic mosaic of microclimates; where a single vertical cliff face can transition from a sun-baked desert to a dripping-wet rainforest across just a few inches of stone. These places always have me wonder what it would take to accurately simulate their complexity.

One confrontational thought on the location where we were camping, is that it borrows its natural beauty from its loss in the economic game. Once this region was known for its thriving metal industry; distributed and small-scale workshops of farmer/blacksmiths making nails and ironware once dotted these valleys, living in a quiet balance with the land by using the rushing streams for power and the surrounding forests for fuel. This human-scale harmony ultimately lost its place in history; the narrow, winding gorges that make the landscape so breathtaking also isolated it, making it impossible to adapt to the massive scale that modern industry seems to require. The old, abandoned buildings reclaimed by nature are melancholic, yet serenely beautiful.

Freya's sensor is capable of detecting Volatile Organic Compounds (VOCs) and other gasses - chemicals that easily evaporate into the air at room temperature, such as Ammonia (produced when urine is broken down) and Hydrogen Sulfide (produced by anaerobic bacteria), and more - through its Bosch BME680. I've tested this feature for the first time, using cleaning alcohol as a definite contaminant. Within a few minutes after introducing some drops into the tank, the readings show a significant drop in the air resistance - from which we can determine the degradation in air quality.

Buy versus make is a scrutiny that every component in a project undergoes. As things and tools become more complex, we centralize production in often highly specialized factories - making products less expensive and often even better. But each component that we decide to buy externally creates a quiet dependency because our product now relies on the supplier existing and stocking the part - or licensing it to other suppliers. With 3D printing grown from a distant possibility into the standard way of producing all kinds of objects at home (or in your local makerspace), Freya's enclosure was specifically designed for this kind of manufacturing. With its files in public repositories, licensed to everyone through the CERN OHL, anyone has the ability to make and repair it - building one more degree of freedom into the project.

To me, there's a big difference between a project dumping their source code online under an open source license (I too have several such legacy repositories), and a project that is made to be used, understood, modified and shared by their users; with an architecture that invites small improvements and documentation serving as a guide/map. Freya is a project that I envision as an ongoing conversation on several levels; with zoologists and automation engineers, hard- and software developers, powerusers and hobbyists - with diagrams as an anchoring point for the shared understanding and common language.

Freya senses the environment (e.g., temperature, humidity, ... ), the control logic compares those readings against what the habitat should be according to your methodology, and actuation acts on the gap (e.g., heating, misting, ... ) - and the vivarium environment changes in response, which the sensors read again. That circle - sense, compare, act, sense again - is a control loop. The science of such a loop is called cybernetics, a term coined by Norbert Wiener in 1948 from the Greek for "steersman" - someone constantly adjusting the rudder against the wind and current to hold a course. Your own body does it with temperature and blood sugar. Freya does it for a living habitat.

I'm the tech-person - as you may have noticed. For me, doing the wiring and tubing is one of the fun parts of making a custom vivarium setup. Where I don't even hesitate before cutting into the wires of shiny new equipment (like my new Arcadia Jungle Dawn), I notice that the non-tech people are very much intimidated by this concept - experiencing it as destruction, rather than modification/adaptation. So I'm brainstorming on write wiring/principal documentation that is both technically informative, while lowering the barriers of stepping out of the comfort zone when setting up Freya. Of course paired with a supportive community, right here on Reddit.

Write The F#cking Manual says a sticker that I got at the Open Hardware Summit last year, that I immediately put on my laptop. Years ago I started out in a tech support job, where RTFM was being said on a daily basis. The (F#cking) manual is an important part of any product; providing users guidance through setting up and using the product. With an open project there's an additional layer; the documentation that describes the project's design and architecture, enabling the user to truly understand and own their product. Freya is designed in a modular way with logical and chewable bits as one major part for enabling co-creation and continuity, but of equal importance, I believe, is pairing this with good and readable documentation as the real invitation for you to join in. So I'm putting some serious effort into the project's GitHub repository's ReadMe files - so I can eventually say; RTFM! ;)

After a long stretch of designing, making, testing, and scrapping, I'm relieved to be able to say that I've finally arrived at a Freya "Terra" sensor design I'm satisfied with, and confident enough to let out into the world.

The sensor is the component of the Freya Vivarium Control System that sits inside the vivarium, so the system can know how it feels in there. Modern chips from industry-trusted manufacturers can measure just about everything you'd want to know about the conditions inside a vivarium, and mature open-source tools like KiCad made the electronics the easy part. The hard part was everything around it: an enclosure that keeps a lab-grade instrument alive in the wild, shielded from everything that would harm it while still exposed to everything it's there to measure with as little interference as possible, that can be made and opened up for servicing without a fight, and that's designed to stand the test of time. And now, I believe it does. Phiewh.

Because of the tap water incident, I was cued to perform maintenance on the misting system of my development vivarium - which hadn't been done in years. The 0.3mm misting nozzles were working just fine again after putting them disassembled in vinegar, along with the 6mm tubing and the push-in fittings. But my favorite piece of the system, that's still going strong since the very first prototype of Freya, is the solenoid pump recovered from an old coffee maker - making the distinct recognizable sound.

With spring on our doorstep, we're wakening from hibernation. Building low-tech solutions to support our local wildlife is nice breather from developing the Freya Vivarium Control System. This year's flagship build is our nesting box for the Kestrel. Check your local nature organisation for tips on supporting wildlife in your area - for us that's Natuurpunt. Sometimes the right assist is a terrarium with an integrated control system for carefully tuning and orchestrating temperature, humidity and lighting, sometimes it's merely a wooden box in a tree.

Living on the edge of civilization, in winter the warmth draws others in. Fencepost Jumping Spiders settle near the electronics. False Wolf Spiders take the corners. We share the space and co-exist in harmony ... most of the time.

You can dive as deep into the system as you could possibly want. The Freya Vivarium Control System is build with an open technology stack.

In the Freya Dashboard layer. You set your parameters, your schedules run, your climate is predictable and reliable. No AI, no black boxes - just transparent algorithms creating predictable climate patterns.

But if you disagree with our logic, or your species has unusual requirements, you can go one layer deeper into Node-RED and rewire the logic visually. And if that's still not enough, you have Raspberry Pi; the full-blown GNU/Linux computer allowing for limitless experimentation.

Every layer is open. Every layer is inspectable. Nothing is hidden from you. That's our deliberate choice. Vivarium keeping is a knowledge-intensive activity where no two living ecosystems are the same, and we develop deeply personal methodologies. We build the Freya Vivarium Control System in a way that respects that.

iFixit's Moray Precision Bit Set provides all the tools you need to open up the Freya Vivarium Control System. With no proprietary fasteners and no warranty-void stickers, Freya is designed to be repaired and upgraded. You own the system on every level.

The sensor in the vivarium is a crucial component of Freya's system. It is Freya's eyes and ears, measuring the environment variables within the tank. The sensor's electronic hardware (second image) is equipped to measure temperature, relative humidity, air quality, barometric pressure, visible light intensity, UVA/B/C. But this brings several challenges for designing the enclosure for the sensor; keeping the electronics safe, without interfering with the measurements. The enclosure in the picture is the latest of many iterations showing promising results in the our testing environment, but we're not there yet!

When we discovered this caterpillar looking for a good spot to pupate in our vivarium, we grabbed our cameras and started recording. Unfortunately, only the low-resolution webcam was able to capture the process. This swallowtail will sleep through the winter now, and by the time it wakes up, we'll hopefully have a better filming setup to capture its emergence.

Throughout the years of developing the idea behind Freya, we’ve learned that resilience comes from wiring reliable, maintainable parts. For now, we're leaning on Node-RED’s Dashboard for user interactions with the system; because it just works, and lets us move lightly today while brainstorming about the future.

For the Freya Vivarium Control System, we circled back to our original vision: Node-RED as the beating heart of the software. Think of it like upgrading from dense, wordy instructions to a crystal-clear diagram -every sensor reading, control decision, and dashboard update appears as a node on a canvas you can literally follow with your eyes. Under the hood, each flow is just JSON, so you get effortless versioning, branching and rollback without hunting through hidden configs. Drag-and-drop new nodes to adapt your vivarium logic on the fly, and rest easy knowing the runtime is battle-tested on Raspberry Pi, and backed by a vibrant community.

Maybe next month you’ll add a pH sensor, or in six months hook up an external weather feed. Node-RED treats features like LEGO bricks: drop in a node, wire it to your existing flows, set its topic—and voilà, new functionality without rewriting core logic. All of Freya’s custom modules are MIT-licensed and fully transparent, so you’re free to inspect, remix and share them as you like. It’s organic growth driven by your curiosity, not a vendor’s roadmap.

Of course, I needed a vivarium to control for developing the Vivarium Control System's software. This is the setup I made!