People are often confused what things are all in the paludarium, what they are called and what they do. In this blog post I’ll explain the different components (sub projects if you will) that make up the paludarium today.
A quick overview
In order to get the paludarium working as it works today, I had to run several different projects and put them all together. First I’ll quickly list all the different components:
- The Cabinet – The custom-built cabinets that hold the paludarium;
- The Paludarium – The glass structure that holds water and air (the paludarium is a closed construction);
- The Land part – The part above water. Filled with tropical plants, and for now no animals here;
- The Aquatic part – The front underwater part of the paludarium, where the fish live;
- The Sump – The rear underwater part. Any excess water from the Aquatic part is dumped here, and the plants living on the background panel get their water from here (and return it there too);
- The Waterworks – The board in the cabinet that holds all the plumbing (water valves etc);
- The Canopy – The intelligent armature sitting on top of the paludarium;
- PaluPi – A standard Raspberry Pi with an RS232 level converter that sits inside the Canopy and handles all the “smart thinking”;
- Apollo units – Named after the god of light, there are around 12 of these units inside the Canopy, each handling up to 4 leds, halogens, TLs or fans;
- Neptune module – Still under development, this unit controls all pumps, valves etc in the Waterworks;
Quite a list right? Everything in this list had to be tuned to each other in order to work. In the following paragraphs I’ll put in some details around each and every component.
1. The Cabinet
Build to carry over 500KG of weight, the Cabinet is basically just a very slightly modified kitchen cabinet:
Built to size (exact height and layout) using standard kitchen cabinet equipment. The normal “legs” that raise a kitchen to its correct height have been left out (as they would cause the cabinet to break apart when loaded over a few hundred KGs). Instead the cabinets are sitting on wooden beams that sit directly under the vertical panels. The wooden beams sit directly on the concrete floor. That allows the cabinet to hold extreme pressures. Read more about it here.
2. The Paludarium
The glass structure itself:
This was also built to size by a company specialized in the construction of (custom) aquariums and terrariums. Its dimensions are 1 meter wide, 60cm deep and 120cm high. It features up to 50cm of water inside. There is a divider inside that divides the Aquatic part from the Sump.
3. The Land part
The Land part is the space inside the Paludarium, above water. The main components here are a beach, a waterfall and the background:
There is more planning involved in this sub project than you might think: Water coming down the background, has to go back into the Sump. Water pumped though the waterfall may in no circumstance go in the Sump (that would cause the filter to drain the aquatic part over time!).
4. The Aquatic part
This is where the fish live! This part is, together with the Land part, the main attraction:
The first fish are already in there:
Soon I’ll post some more images of the Aquatic part. Just waiting for my Anableps to arrive!
5. The Sump
the Sump is basically the gutter of the Paludarium. Any excess water (for example when fresh water is added) is spilled over the divider into the Sump. Rainwater should largely hit the background and go into the Sump, and water used to moisturize the background is actually pumped out of the Sump, over the background back into the Sump.
Any excess water in the Sump flows directly into the sewer through a thick pipe:
6. The WaterWorks
The WaterWorks sit in the cabinet, and contains most of the plumbing. The Paludarium uses valves, heaters and reverse-osmosis. The Waterworks contains all of this stuff:
The valves on here will be controlled by the Neptune module.
7. The Canopy
Now here it gets serious. The Canopy is the light armature that holds all lighting, fans and the Paludariums “Brain” (The PaluPi). This Canopy was originally built for the first Paludarium (version 1.0) and was largely reused for the current version 2.0 of the Paludarium.
Looking up into the Canopy, it looks something like this:
You can actually see all of the small PCBs sitting inside. Those are the Apollo units. Fans on the right, and top right the PC power supply that is used/abused for all low voltage stuff (the LEDs are run from 5V, the Halogens from 12V).
The actual “brains”, the PaluPi is hardly visible at all. On the image above, it sits directly under the power supply. As it is built into a black housing, it is hard to see. The white thing on the left is the TL ballast that runs and dims the TL lighting.
8. The Paludarium’s brains: PaluPi
PaluPi is the highest level of intelligence inside the Paludarium (maybe the fish are smarter though 😉 ). PaluPi is actually a Raspberry Pi. It is connected to the internet via ethernet, and talks to all electronic components using the serial port. In order to be able to do this I mounted a small PCB on the Pi:
For more details on how the serial communication works, see here.
So what do the brains do? A lot of things. I’ll list some of the highlights here:
- Fetch data from the La Selva Biological Station (see here for more details);
- Store the La Selva data in a local database;
- Use the data in the Database to calculate values the Canopy needs to do lighting etc and send them out;
- (future) serve a website around the real-time and stored data.
9. Apollo units
The Apollo units are named after Apollo, the god of light. The Apollo units are extremely basic controllers. They are based on Atmel AVR controllers of the ATtiny2313 type. They feature 4 PWM outputs and optional 4 digital outputs. The units each have a unique address so they can be accessed individually. They also have several group addresses so when sending a group command all units will be listening in. This is what they look like in detail:
There are four subtypes of them:
- LED – These Apollo’s dim four 1W power LEDs;
- HALO – These Apollo’s dim four Halogen light (20W each) and look very much like the LED units;
- FANS – This is actually a single Apollo unit inside the Canopy. It controls three fans and the two TLs;
- RGBs – These Apollo’s have a different PCB. They are specific designed for high power RGB LEDs (3x 1W) for night lighting etc.
These little units only have 2KB (yes – KILObyte) of flash memory onboard. Needless to say that they are simple, direct and bug free. They have already done 2 years of service in Paludarium 1.0, and now continue their work (with only slightly adjusted software) in version 2.0 of the Paludarium.
10. Neptune unit
The Neptune module is under construction:
It is like an Apollo unit on steroids. It is based on an Atmel AVR Mega32 controller. This controller is very much bigger, and can also read analog values. This is the one big single unit that will control and measure everything necessary and it does not sit in the Canopy, but close to where it needs to function: Next to the WaterWorks inside the cabinet under the Paludarium.
So what does this unit do? It does the following things:
- Control the three water valves (tapwater, rain, reverse osmosis);
- Control the aquatic heater;
- Control the pump that moisturizes the background of the Land part;
- Control the CO2 valve;
- Control the mistmaker;
- Control the RGB light strip under water;
- Measure aquatic temperature;
- Measure air temperature and humidity;
- Measure pH values;
- Measure water conductivity.
Quite an impressive list, right? The above things are done using several technologies. For starters, there are 8 relays mounted on the PCB that can directly switch mains voltage. That allows the Neptune module to directly switch valves, pumps etc.
The RGB strip is controlled using powerFETs (IRF540’s), just like the Apollo units do. These FETs connected to PWM output allow a very detailed control of Red, Green and Blue (each in 256 steps of intensity).
Finally the Neptune module measures things. It uses the internal A/D converter in the Mega32 for all measurements but the air temperature and humidity. Those are measured by a specialized chip (Sensirion SHT11) and are read digitally by the Neptune module (and then sent back to the PaluPi).
Most of the sub projects are ready or almost ready. They have all been integrated into each other, and the Paludarium now works for the larger part. Inhabitants are already present! There are two main things that remain to be done:
- Completion of the Neptune module and adding some code in the PaluPi to support it;
- Construction of a web server on the PaluPi that delivers buttons, graphics etc. on the Paludarium.
Still a lot of work, but the payback is largely already there…. Right now the Paludarium is a real treat to look at!