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Fighting Against Water Part II - effective waterproof 3D printed enclosures that do the job

3D-Printed Waterproof Case for SCK 2.3

Hello everyone!

We have been exploring ways to develop a waterproof case using only 3D printing.
The idea is that anyone can easily access an enclosure design using the most common tool in our workshops — a 3D printer.

This enclosure was developed during the CitiObs EU project and deployed in Oslo.


Design Concept

The enclosure consists of several layers of 3D-printed pieces, with different materials in between.
The goal is to make it as difficult as possible for water to seep through the printed layers.


Outer Layer

The outer layer is the thickest one and is directly exposed to the environment — rain, wind, snow, and sun.

We chose PETG for its reliability in outdoor conditions and for its flexibility, which should help it withstand temperature changes between winter and summer.
This part is printed in white to avoid overheating.


Second Layer

The second layer is also printed in PETG, but it is much thinner and in a translucent color so we can see the gap between the first and second layers.

Before assembling them, we covered the outer side of the second layer with a thin plastic bag secured with a rubber band. This way, we gave an extra level of waterproofing to ensure the electronics are protected.


Foam Insulation

The gap between the two PETG layers is filled with polyurethane foam, which serves three purposes:

  1. Waterproofing the entire structure
  2. Thermal insulation for the inside of the box
  3. Bonding the two printed parts together

This “shell” should give us good protection from the rain!

In future iterations, we hope to try cleaner options maybe with recycled material, but this time we wanted to ensure that the electronics were well protected.


Inner Layer & Electronics

The inner layer is printed in PLA to make it easier to produce.
It includes a base where all the electronics are mounted.

In this case, we only needed to measure a few parameters, so the Sensirion SEN5X sensor was used.
This version provides PM measurements and includes an internal temperature and humidity sensor, with VOC and NOx indexes.


Field Test in Oslo

This enclosure has been in use in Oslo since the end of January 2025 as part of a pilot deployment.

A total of 20 Smart Citizen Kits equipped with the 3D-printed waterproof enclosure were installed in various outdoor locations across the city.
The goal of the deployment is to evaluate the enclosure’s long-term performance in Nordic weather conditions while collecting environmental data such as PM (particulate matter), temperature, and humidity.

These units are actively transmitting data to the Smart Citizen Platform, where they can be monitored in real time.

You can follow the live readings and see the project details here: 3D Printed Enclosure for Outdoor.

Field test in Barcelona

Barcelona is also a good place to test these devices, especially in summer, with hot conditions mixed with torrential downpour. We have installed a device with a solar panel (subject for another topic soon!)

You can see the link to the device here: https://smartcitizen.me/kits/18206.

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Hello everyone,

we are aiming for a long-term, low-maintenance installation of a 2.3 Kit in a remote location, so robustness against wet and cold conditions as well as reliable power supply are key for us.

That’s why we have these following questions:
Do you have any estimation of when the complete design files (STLs / CAD / bill of materials) for the waterproof enclosure will be available, especially adapted for the 2.3 Kit?

Is it possible to combine this model with a solar panel setup without major modifications (e.g. panel placing, cable routing, waterproof connectors)? Are there already examples or plans that include solar integration?

Thanks a lot for any insights!
Best regards,
Laszlo

Hi!

Do you have any estimation of when the complete design files (STLs / CAD / bill of materials) for the waterproof enclosure will be available, especially adapted for the 2.3 Kit?

@adaisuri is now on a short leave, but he’ll upload the designs over to https://enclosures.smartcitizen.me next week.

we are aiming for a long-term, low-maintenance installation of a 2.3 Kit in a remote location, so robustness against wet and cold conditions as well as reliable power supply are key for us.

For this particular case, I’d evaluate what variables you are looking to monitor in your campaign and see if the current system is the most adequate. For instance, I’d suggest to evaluate if the Urban Board is necessary:

  • If it is, I’d suggest resins for protecting the circuit boards (see https://thecavepearlproject.org/ for recommendations)
  • If you don’t need the Urban board, but need the PM sensor, we can provide small adapter boards to connect a SEN5X series (which can also have T/RH) from our side (send an email to info@smartcitizen.me) or that you can manufacture yourselves.
  • You can always use an external sensor via the auxiliary port.

In the design above, we decided to not use the Urban Board so that it was easier to protect the system. A similar design could maybe use a commercial IP box. This makes it simpler for protecting and avoiding corrosion.

If you are planning on deploying on a remote area, you may want to test options for connectivity via 4G-LTE connectivity here: 4G - 5G Compatibility - #2 by oscgonfer. We are also working on a mesh based solution, but if you have SCK2.3, that’d be the way to go.

In terms of power supply, if you have an option of AC power permanently, a power supply such as this one: Power Supply - Smart Citizen Docs is the best option. Otherwise, you can use a solar panel, but depending on the system location and consumption, you’d probably need different sizes and batteries. More details n a separate post and in the docs: Solar Panel - Smart Citizen Docs

Is it possible to combine this model with a solar panel setup without major modifications (e.g. panel placing, cable routing, waterproof connectors)? Are there already examples or plans that include solar integration?

Yes, the input to this design is still USB. An external MPTT is used to provide 5V power with micro-USB. We used this one: https://docs.smartcitizen.me/hardware/addons/solar-panel/#bom

However, you can also use a more advanced system from Voltaic Systems: Solar for IoT and Remote Sensors | Voltaic Systems (distributors available in Europe).

Let us know!