dragonator

I seem to remember that freezing temperatures are dangerous in a heat exchanger. It does indeed clog up with ice if you have it. From what I have heard in the case of frost is that people put big underground channels to preheat the air to just above freezing. Filtering is always a good idea on both sides. You'd be surprised how much dust is in the air for an exchanger to accumulate.

Hello Vlad,I have seen your progress, even though I have not really found much time to answer.Your tests looks amazing. I had hoped to test myself last winter but I sadly did not have the time. I wanted to make a proper massflow meter so I can do true efficiency testing. Your results seem almost too good to be true. I can understand that you are skeptical. The basic design does have a lot of surface area, so it is not out of the question. One important thing to look at is not just the temperature in, but also the humidity. If you want to make sure the numbers make sense, get all 4 temperatures and humidifies, 2 at each end. From these values you (or I) can derive the efficiency and unbalance of the exchanger.Good luck. I can't wait to see more.

The distance between the outer and the inner tube is what matters. This needs to be as thin as possible. The relative diameters do not matter.

90mm is the outside diameter. 89mm should fit.

The moon ring is one of the more fragile parts but I have not ever felt like it would break. The main argument would be that it is a really complicated part to install.In principle the orrery should also work upside down but at this point I do not know if all axes will remain in place with the orrery upside down, but they can be secured in place.It would be an amazing lamp. Bear in mind that the feet will need to be glued in place or replaced is mounted upside down.

Not exactly lying around, but I do have them yes. The module on most of the gears is 1. The big ring and the tiny gear on the moon have a module of 1.25 to make the scale work out. If you need anything more let me know.

Relocated to Ytec3d.com. They are still available for download.

I do not really understand the question. The way I built my tube can be scaled indefinitely.

I mostly print in PLA

Congratulations on winning first prize. I think it is well deserved

Thanks, good luck in the wizarding contest.

The Uno has several pins that match with the schematic in step 10. These are the pins that you can connect to the Uno. These pins are A5, A4, D7 and D8. Also you will need to connect the 5V and the ground. The crystal and programming header are on a normal uno, so you won't need to add those.

When I saw the first pictures, I did not imagine this thing to be made of paper. It looks like it is made from something more like wood. I never thought of this way to make stuff by hand. It may take time, but the end result is amazing and can be made by without any special tools. There is a 3D printing technique like it called LOM, if you are ever interested to see.If you are worried at it's strength, there might be something you could try especially with paper. You could try and impregnate the paper with a watery super glue (CA). I used it myself to impregnate gypsum parts to make them stronger. The super glue should soak into any paper part and set within an hour. After that, the part should be an order of magnitude stronger. In the Netherlands there is "Bison seconde lijm"...

When I saw the first pictures, I did not imagine this thing to be made of paper. It looks like it is made from something more like wood. I never thought of this way to make stuff by hand. It may take time, but the end result is amazing and can be made by without any special tools. There is a 3D printing technique like it called LOM, if you are ever interested to see.If you are worried at it's strength, there might be something you could try especially with paper. You could try and impregnate the paper with a watery super glue (CA). I used it myself to impregnate gypsum parts to make them stronger. The super glue should soak into any paper part and set within an hour. After that, the part should be an order of magnitude stronger. In the Netherlands there is "Bison seconde lijm" which is really strong and works well for gypsum. You can get it in any home improvement store there. But beware to do it in a ventilated area without breathing the fumes. CA fumes are quite nasty. I know this from experience.

I have had little problem with this size tubing, but I will remember that when it is more critical or when I need to bend bigger tubes. Thanks.

Well it is mostly 2 normal sized servo's and 2 micro sized servo's, a few led's and a laser diode. I also used a joystick module. All of those don't have to be expensive. You can get decent servo's for 5 euros each. All other parts mentioned are under 1-2 euros.

I don't know how much use it will be, it is quite chaotic, but I added it as an attachment to Step 1.

I don't do thingiverse anymore. Short version is that I lost all of my goodwill toward Stratasys and Makerbot, and stopped using it.

That is a problem I did not solve. The 'easiest' way of doing it would be assembling the planets as it is right now, but sadly you cannot slide the planets in their current position.

I don't think I myself could make this a kit for an interesting price. I charge somewhere between 5 and 10 euros per hour for 3D printing, and printing takes at least 10 hours. Other materials come to roughly 20-30 euros. Think around 100 euros, but that is from the top of my head.Classroom might be a bit challenging, but die-hard hobbyist should be fine.

I would like to have made it with the right scale and distance planets, but I am afraid that both my 3D printer AND my house are not big enough for that. Even with the examples I have seen I myself have a hard time grasping just what the scale really is.

You can upscale any model before slicing, but there are bearing holes and shaft bores that need to be more or less what they are now. If you want to scale it up much (think more than 5%) you will need to modify the parts so that they themselves are bigger but the bores and bearing holes aren't.I still have the source files available and can share them if you have solidworks. I can share Step files if you have a program that can handle them. If you don't have this software and still need it up-scaled, I might be able to do it, but it might take a while.

I made the paper template. It provides more accuracy than the orrery requires. I tried making a pipe bender but after I discovered 3mm pipe can still be bent by hand without collapsing I ditched the idea.

Making one out of legos is way more complicated than 3D printing one. Lego gives less options for the used gears. You have my respect. I too did the gears by hand first, but that took forever and at some point I was completely done with it. The excel sheet is not perfect but it only took me an hour, so it was totally worth it.

I did consider painting the planets but getting them to look good would have been difficult with my tools. Instead I printed the planets in Bronzefill and polished them. This gives a different look, one that I am quite pleased with.I am curious to see what you will come up with. If you need any more information you can always ask.

I did. It is the easiest way to get bronzefill to shine so I designed and made a small motorized glass jar with screws. It is not the fastest but it does work.

The cap goes from 5V to ground and cancels the noise of the stepper motor. Closer to the stepper motor driver is better.

Hardware wise not much. Both are powder and inkjet printers, both use the HP C6602A and both are decent, but more there to prove a point an be useful as a stepping stone. Both are at this point no longer supported.If you want to start a 3D thing as a hobby, I advice against powder. It is difficult, messy and has very limited uses. Start with FDM or DLP.