Progress on the Aeryn module

Building out the new paludarium follows two “golden” rules: 1) No tech inside 2) create everything in a modular fashion. Following these rules I came up with the Aeryn module. This module is in charge of one of the most important things for the land portion of a paludarium: Conditioning the air.

Requirements for the Aeryn Module

The Aeryn module should be able to utilize the surrounding air (my living room) and convert that into “jungle-compatible” air. In the early stages of building paludariums I quickly discovered that airflow is the number one factor to influence humidity. Heating the air used to be done by heating the water mass, and the air would more or less follow that temperature. Adding a mistmaker inside the setup would allow for quickly rising the humidity.

In the new setup I wanted to pack all of this (and more) into a single replaceable module: The Aeryn module. These are the requirements I set:

1. Airflow that can be regulated
The module needs to have one or more fans that can be regulated in RPM and measured back by RPM. The fans needs to run 24/7 to be able to keep moisture from creeping back up into the module. Running at idle RPM should create a small airflow just large enough to keep the moisture out of the module.

2. Air can be heated
The module should allow for the air being blown into the paludarium to be heated.

3. Air can have raised humidity
The air being blown into the paludarium has to have an optional raised humidity, preferably in several steps.

These three things ended up in a three-step approach inside the Aeryn module as I’ll show next.

Stage 1: Regulated Airflow

In order to regulate the airflow, I have chosen to use 120mm computer fans. There are many different types, but I settled on the 4-pin fans as they have the ability to regulate their airflow (PWM) and also measure their RPM back. A standard 4-pin 12VDC fan header was constructed on the Artemis controller to support a single 4 pin fan.

As the Aeryn module needs to compress the air into a small tube (40mm in diameter) that will inject the air into the paludarium, I wanted more air moved with less noise, so I settled for a dual fan setup. Both fans are connected together and run at the same controlled PWM, and only fan 1 gets its RPM read.

These fans suck air from the top of the cabinet, and a 3D printed “slide” converts the airflow from “down” to “horizontal”:

The airflow that now runs horizontally through the module will enter the heating system next.

Stage 2: Heating the air

If needed, I want to be able to heat up the air. The way I constructed this was by getting an electrical heat pad (that automatically switches off above 70 degrees celcius) or 120W / 220VAC. This heatpad is glued onto a large heatsink. The air is forced through this heatsink, effectively cooling it while warming up the air:

The heating pad can be switched on and off using a relay on the Artemis controller. The Artemis has a total of four 230VAC switching relays. I try to keep as many loads as possible at 5, 12 or 24V, but for a heater this just does not make sense.

Stage 3: Adding humidity to the airflow

The last (and most complex) stage in the Aeryn module is where it adds humidity to the airflow. This requires a lot of components… The idea is to first have a container with (osmosis) water where the air flow over. Inside the water I need one (preferably 2 or 3) mistmakers. I need to measure back the water level as the mistmaker may only run when the water level is high enough; finally I need a way to add the water, and to overflow any excess water:

The container I got from Ikea, the hood I 3D printed to size.

For the water I decided to connect the water container to the reverse osmosis unit. Using a valve I can optionally fill the container under the paludarium with osmosis water (for rain etc), or fill this container. There is an overflow leaving the Aeryn module, which I guide into the aquatic part of the paludarium. This will be used to fill / change the water automatically. As an upshot the container for the mistmakers is always filled this way.

Putting all pieces together

Finally I was ready to piece everything together; several 3D printed airflow guides were put in to make the air flow as fluent as possible. Finally I was ready to close up the Aeryn module:

Finally it was time to slide it in its holders inside the hood. It was difficult to guide all of the wires while putting in the module, but it eases my mind that I can always remove it, make changes, or create a replacement module if needed:

I am now putting the Aeryn module slowly through it’s paces. The fans run perfectly, the air flows out nicely. Heating also works. What remains to be tested is the most complex part: Filling the third section with water and starting up the mistmakers. To be continued!