how i'm building my fishroom (aquariums), and what i do to automate it and make it smart.
With most aquariums, you need a filter to remove muck, and also to extract toxins from the water. I used to make filters out of PVC tubing, but i decided to design a filter that would be fully 3D printable, and modular. I may create a separated project for it later, but here's a video explaining it :
Compared to other DiY filters, this one takes longer to physically create, since you have to wait for the printing. However the printer works alone :)
Assembly is fast (a few minutes), and the filter can be altered, expanded, modified, etc...
If you want it larger, simply print more chambers and install them!
See you next!
In the last post, i presented the waste water management. This time i improved it :
Cheap plastic ball valves for the win :)
In the previous post, i described how i built the water output for the room.
Today i made a small video (sorry for the audio quality at the start of the video), showing how i use this newly installed system to make my water changes easy :
Previously, we saw how water comes into the fishroom. So we have a water source to make top-ups, to compensate evaporation. However, for water changes, we have to throw away dirty water. In this post we'll focus on adding a conveniant way to throw water away.
This is simply done using 40mm PCV piping. The idea is to have an horizontal pipe (with a slope), to get water from near the aquariums, to the outside.
To get water IN the pipe, we need an access. For that purpose, i added four T PVC pieces on this pipe, with the openings vertical. Each T recieves a 20cm pipe. We thus have a few upward pipes, opened at the top.
This is then a matter of introducing a smaller diameter flexible tubing, and doing a siphon from the aquariums. We have an exit near each aquarium, so that we don't need long tubing to siphon, as shown on the picture below:
The previous circuit joins a second pipe that gets the water near a hole to the outside.
Here is what it looks like (dry fit, not in the good orientation) :
So, once everything was good, i glued the circuit in 2 parts, and one joint is just friction fit, to keep things adjustable.
I tried it, changed aproximately 100 L of water with no leaks, and without a sweat :)
This makes it so much easier to do the water changes, i will now be able to maintain pristine water quality!
I tend to consider that for a security system (such as a blade guard on a circular saw) to properly work, it must be easy and conveniant to use. Otherwise, users bypass it, or don't use it at all. I applied the same philosophy here : for me to do my water changes, they have to be easily done, so that it's not a chore.
All of those systems are meant to house my fishs and shrimps. It has other no relation to this very post, but i can, so here are two 4K pictures of my Neocaridina Davidi Sakura red shrimps, with a berried (she has eggs under her belly) female :
And now two females, with the one in the background beeing the berried one :
Here is a very young (2 weeks top) baby shrimp in the same tank (aproximately the same scale on the picture):
it is this hard :
This is a 4mm wood drillbit, and it got like that when i was drilling the wood...
For sure, it wasn't a high quality drill bit (quite the contrary) and the tip was a bit dull (hence the force i applied). However, it never happened to me prior to this, even with bent drill bits...
On the other end, metal drill bits drill perfectly trough this hardwood, with clean, nice edges.
However, i had no problem drilling with a quality 4mm wood drillbit (quite a long one, because i had long screws), but i had to be more careful (slower, cleaning the bit more often).
I made a little VLOG on youtube to update you on my progress :
Sorry for my english, i'm a native french speaker and didn't practice english for a few years :(
This project uses nice wood, so i went for a natural finish. First step was sanding :
As you can see, sanding dulls the figures of the wood, but it's not a problem, it will come back once some finish is applied.
Indeed, here is the same piece, with one fresh coat of transparant oil :
At this stage, the oil raises the grain of the wood. I thus sand it with fine grit sandpaper, with the oil still wet. This is a very light sanding, and it helps removing the risen wood grain, but doing it with the oil wet causes the wood dust to fill any cracks on the surface, giving a very soft touch.
With this oil, you're supposed to use a clean rag to remove any excess. In this case, i did apply just the right amount to save on product (that's my last bottle of transparant oil, and there's none at the store, so i wanted to be sure to be able to finish the pieces).
After a few hours (it's 27°C in here, tropical place, so no winter ;) ), it has dried, so i can sand lightly with fine grit sandpaper, then apply a second coat. Rince and repeat for as many coats as wanted; recommanded is at least 3.
Indeed the second and third coat revels the figures of the wood even more; but i stopped there to conserve oil.
Since this oil doesn't release nasty chemicals in the air, i'll be able to add more coats later on, on the assembled rack in the fishroom (anything releasing dangerous chemicals is banned from the fishroom : shrimps are very sensitive, or at least supposed to be. I'm taking no chances here.).
On the picture above, you can see the oiled beams (still wet, you can see that it's milky before drying), as well as the oil can i used.
it is Syntilor Oil (natural finish) for furnitures and work surface. It has an A+ for emission rating, meaning very few emissions. It's easy to apply, gives a good finish and tools clean with water, so no need to use smelly chemicals to clean your brush.
Now i have a sturdy structure, but i need some surface for my tanks to rest on.
For that purpose, i routed a 18mm deep cutout on all the internal edges of my beams :
It's 18mm deep because 18mm hardwood plywood is common here.
So i routed the beams, and the foot assembly on the inside, until i could fit two 1030*520mm planks, one on each side of the central divider.
It was quite some work (hard wood is simply HARD!), and i had to make quite a few passes, i probably took 1 to 2 hours to route it to the correct depth.
One of my plywood sheet was too long because of reasons so i recut it on my table saw.
I had some chiseling to do to get the corners square (so that i can change the plywood sheets if i want to without any extra work : preferable than sanding the corners round each time!), and at last the plywood sheets did fit :
i'm building my aquarium rack layer by layer. So now i'm building the first stage of it. This level will support multiple small (50 liters, aproximately 15 gallons) aquariums (up to 8), so the load won't be extreme, however i want to be able to change my mind later.
Furthermore, the levels above will rest on this one.
in order to minimize risks, i chose a design that will transmit the weight to the ground mostly by the legs. Indeed, the beams that support the weight stand directly on the legs. Further levels will also stand directly on those legs, so we should thus reduce the possible flex.
Here is a model in openscad. The beams are 60*50mm section (aproximately, i cut those from raw lumber).
The legs (in red) are joined together by the orange beam, with 8 screws (4 on each leg), going alond the Z axis. I used 5mm*80mm wood screws, and countersunk the head 20mm deep. I also used some wood glue on those joints.
On the picture above, you can see the leg assembly.
I thus have 3 parts like that, giving me the 6 legs of the stand.
The next step is to add the yellow beams. I simply screwed those on the legs assembly from below (z axis, + direction), and countersunk the screws heads as well. I carefully placed each of those beams so that the long, brown beams are flush with the front.
I tried to join the yellow and brown beams with pocket screw holes, but i didn't manage to properly do that. So instead, the brown beams simply sit on the legs, and are secured with one 5x80mm wood screw, with a countersunk head.
This construction makes the rack extremely sturdy along the Z axis, but it is a bit weak along X. The forces will mainly be exerted along Z, but an earthquake can generate quite some lateral forces, so i'll tackle this issue in an upcoming log.
A quick post on humidity sensors here. I was reading this HAD article on Statistics (great reading by the way), and noticed the use of DHT11 humidity sensors. DHT11 are worse sensors than DHT22, and to speak frankly, the DHT22 is already quite crappy to begin with.
Why is that? first of all, it's communication protocol is something weird that you'll use only for this sensor, unlike 1wire that is used by multiple sensors (ok, in all honesty, we use it almost only for DS18B20 temperature probes, but other stuff exists, and at least there are cool things with this protocol, such as unique adresses, the fact that it's a bus and uses up only one GPIO for whatever number of sensors, etc...) or I2C that is used by loads of sensors.
Why does it matter? Well if you design a board for some application, and you have somewhere to put I2C devices, you can reuse it for other applications. On my ESP8266 breakout board, i did put KF2510 connectors with 4 pins, for I2C (VCC, GND, SDA and SCL), and i use the same boards for loads of projects.
With a DHT11/22, you have to put the pull up resistor between vcc and data for each connector, meaning that you can't use it for something else that doesn't require a pull-up, or require another resistor value.
Another problem with this sensor is that it has low accuracy and low resolution. Perhaps i've always gotten bad ones, but two sensors rarely return the same value in the same environement (several °C of difference, and 5-20% of humidity difference....).
What is the final nail in the coffin of those sensors is the cost of good quality sensors : the BME280, made by bosh (at least we know from where it comes from, as well as have access to ONE comprehensive datasheet) costs 2€ on a cool little breadboard that works out of the box on many µCs or systems.
On top of that, you add a good temperature sensor, and a barometer along, all with much better resolution and accuracy. In most cases, in similar conditions my BME 280 sensors return very similar values, or pretty damn close to that.