Show HN: Oasis – An open-source, 3D-printed smart terrarium

[jbuch]

https://github.com/justbuchanan/oasis

See the website for a demo video: https://oasis-terrarium.com

This project is an enclosure for growing plants. Features include:

  - high-power LED lighting
  - a built-in water tank and mister
  - fans for airflow
  - temperature and humidity sensing
  - wi-fi connectivity and a web-based interface for control and monitoring (see https://oasis-terrarium.com/docs/usage_guide/#web-interface)

The entire project is open-source:

  - electronics: designed in KiCad
  - 3D models: designed in CadQuery
  - software: written in Rust

I initially started this project during COVID and built a working prototype using a Raspberry Pi and off-the-shelf parts. The first prototype worked, but was pretty rough. Several months ago, I picked up the project again and began a complete re-design. After two rounds of circuit board design and countless iterations of the 3D-printed parts, I'm finally happy with the results. Along the way I learned a lot about electronics design and fabrication, 3D modeling, and Rust.

Happy to answer any questions - thanks for checking it out!

Here are some direct links to parts of the project you may find interesting:

  - demo video: https://oasis-terrarium.com
  - detailed build guide with pictures: https://oasis-terrarium.com/docs/build_guide/
  - interactive 3D model: https://oasis-terrarium.com/docs/3dmodel/
  - detailed info on electronics design: https://oasis-terrarium.com/docs/electronics/
  - 3D-printable models: https://www.printables.com/model/1315117-oasis-smart-terrarium

[craghack]

Well built and a great write up!

Addressing some of the comments/concerns in your documentation:

* To protect the ultrasonic mister from bad firmware frying it, you could probably replace R6 with a sufficiently sized capacitor to make an effective DC block

* I've also had issues with a thermal sensor just reading board temp, best solution is to make the sensor a separate board. Short of that, one can mill slots around it and reduce copper pour to reduce thermal conductivety from the PCB.

[jbuch → craghack]

Thanks!

> To protect the ultrasonic mister from bad firmware frying it, you could probably replace R6 with a sufficiently sized capacitor to make an effective DC block

That is an excellent idea - I'll definitely keep that in mind for a future version.

> I've also had issues with a thermal sensor just reading board temp, best solution is to make the sensor a separate board. Short of that, one can mill slots around it and reduce copper pour to reduce thermal conductivety from the PCB.

I ended up just moving the sensor offboard and as far away from the heat source as I reasonably could. I did consider the milled slots + reduced pour option, but given the amount of heat generated by the LEDs, it seemed best to move the sensor further away.

[craghack → jbuch]

Most of my time designing hardware is spent trying to find ways to prevent the doofus writing the firmware from releasing the magic smoke. I am that doofus

[ravdar]

what's the total cost of building this? and how long would it take?

[jbuch → ravdar]

Total cost is roughly $110 USD, but there are a couple caveats to that price:

  - some parts are sold in multiples, so you'll have to buy several even if you only need one for the build
  - I ordered the electronics from JLCPCB where the minimum order quantity is 5 (minimum assembled is 2). At a quantity of 5 assembled, the LED board is ~$12/board and the mainboard is ~$41/board. If you're comfortable with SMD soldering, you can order bare PCBs and parts and do it for much cheaper by assembling only one of each board. You can find some more details here: https://oasis-terrarium.com/docs/electronics/#how-to-get-them. And a history of my JLCPCB orders including costs here: https://oasis-terrarium.com/docs/electronics/#pcb-order-history

With those caveats in mind, the rough breakdown is:

  - custom electronics: $53
  - 3D-printed parts (~600g of PETG): $12
  - other parts: $46

As for build time:

  - acquiring/assembling electronics: this can vary a lot depending on whether you buy assembled or do it yourself
  - 3D-printing: depending on your printer, maybe 2 solid days of printing
  - waterproofing 3D-printed parts: takes ~15 minutes to do and 24hrs for the epoxy to cure
  - final assembly: 30-60 minutes

[Aurornis]

This is very cool. You've done a great job with the instructions. I understand why you didn't write much about the best plants, but for those of us who are new to terrariums could you share a link about where I could learn about terrarium-appropriate plants and where to acquire them?

[jbuch → Aurornis]

Thanks!

I'd recommend @SerpaDesign on YouTube as a great source of info on terrariums - he's got quite a few videos that cover this, but here's one to start: https://www.youtube.com/watch?v=7Lg4tzkHgVo&t=1s&ab_channel=....

The main thing to keep in mind is that terrariums are high-humidity environments, so plants like mosses, ferns, and orchids will do well. Plants that prefer a dryer climate like succulents and cacti will not do well.

Another consideration is lighting - some plants want more, some want less. This terrarium is capable of fairly high light output, but can also be set to any level you want. However, you'll want to select plants that want a similar amount of light so they can co-exist with the same light settings.

[deadbabe]

I don’t think LEDs work. Don’t you need full spectrum lighting for a terrarium?

[jbuch → deadbabe]

Full spectrum would be more optimal, but the 5700k "daylight" LEDs I'm using still work very well. They're probably lacking a bit on the red end of the spectrum compared to a full-spectrum light, but otherwise they cover the photosynthetic range pretty well. See page 19 of the datasheet for the LED spectrum: https://downloads.cree-led.com/files/ds/x/XLamp-XTE.pdf. And here for some decent general info: https://www.neherpetoculture.com/vivariumlighting101.

Anecdotally, I've successfully grown a range of plants in these including mosses, ferns, and orchids.

[ge96 → deadbabe]

I use these ultra bright led lights from LOWES the daylight ones have been able to grow random stuff like Apples/Mangoes/Pomegranates/Bell Peppers/etc... not as good as being outside but it does work 12 hrs on/off

[dwroberts]

This is a really cool project thank you for sharing.

I'm prototyping my own similar kind of thing right now - an enclosure for growing culinary mushrooms - so seeing how you've used and attached the humidifier discs is really useful inspiration.

On humidification - have you considered decontamination for the water? I think bacteria and scum build up is an issue, and I've seen heavy duty equipment incorporate e.g. a submerged UVC light for trying to keep it clean. I wonder whether it's possible to do similar on a small scale by using a UVC LED (obviously need to be careful with safety though)

[jbuch → dwroberts]

Thanks!

Sounds like a fun project, best of luck! Would love to see what you come up with. One word of warning with the misting: using them in an "upside down" configuration as I'm doing can be a bit finicky. I've encountered some that slowly drip due to the pressure of the water above them. Look for misting discs with small hole sizes (<=4uM) and expect that some percent of them won't work well. However, the ones that do drip at the start typically stop after a day or two of use and are fine from there on out.

I have not really considered decontamination and I don't think it's much of an issue for terrariums because the plants and soil in the enclosure already contain a lot of bacteria, etc. I could see it being much more important for your use case with mushrooms where a small number of mold spores can ruin an entire mushroom grow.

[yreg]

It would be nice to see the default dimensions of this thing on the landing page.

[jbuch → yreg]

Thanks, just added that.

[senectus1]

oh wow. I really want something like this at my desk.

I may have decided on my next project!

[iancmceachern]

This is awesome! So much better than that MiT openAg thing.

[mandsgoo]

Ive always wanted to do something like this. Nice!

[bethekidyouwant]

I like it, but it is not mostly 3-D printed.