Ultrasonic Anemometer Part 17: Lasercut Mechanical Design

20160228_Projekte_133

In my last two posts I have gone through my new anemometer circuit both in theory and practice. Click here for an overview over my ultrasonic anemometer project.

20160228_Projekte_110

This will be a short post. Unlike most of my other posts, this one will not cover electronics but the physical design of this wind meter. As you can see, the new design all laser cut. At the Zurich Fab Lab I have access to a 75 watts Epilog laser cutter and I recently started playing around with OpenSCAD, an open-source CAD software.

20160228_Projekte_102

I immediately liked the OpenSCAD approach of designing a 3D part in code as opposed to a graphical interface with menus and buttons and the like. Using OpenSCAD is much like writing software. If you’re more familiar with coding than you are with classic CAD tools you will instantly feel at home with OpenSCAD. But it’s pretty much love it or hate it. At least with all the people I’ve talked to.

20160228_Projekte_099

I’ve seen some quite cool boxes  that were just laser cut and then screwed together. I found it quite compelling how you can laser cut your parts, stick them together and maybe use a few screws to hold everything in place. So I decided to give it a try myself.

20160228_Projekte_132

The design is not too complicated with just 6 wooden parts. The material is 5mm in thickness so I looked around for screws and bolt that would be appropriate in size. I also thought that it would be nice to use square bolts both from an optical as well as a mechanical point of view. I learned that square bolts are specified by DIN562 and that M2.5 square bolts measures 5x5x1.6mm – exactly what I needed.

20160228_Projekte_109

So the next thing to find was M2.5 screws. I found nice ones in stainless steel and especially with a Torx (T8 size) head as specified by ISO14580 as well as some matching washers (DIN125).

20160228_Projekte_130

All the tubes are recycled from my last model. Just standard 16mm plastic pipes intended to hold electrical wiring.

20160228_Projekte_104

As you can see in the photo above, I’ve tried two different versions for the side parts. The one at the bottom takes the path usually followed: There are cuts that can later fit the screws. The one at the top doesn’t have those cuts and relies on holes being drilled by hand.

20160228_Projekte_127

Drilling those holes turned out to be really easy. After the parts are ready, just stick them together and drill the holes using a drill press. At the fab lab we have such a drill press and the holes were drilled within minutes. I never liked those cuts so for me this was the way to go.

20160228_Projekte_128

The new design gives me a lot of space to mount any PCBs and hides all the wiring between the bottom and top plate. The bottom includes a large square hole so everything inside stays accessible. There are also two small drill holes to mount a 12 volts power supply. This way I can just plug it into the wall which I think might be handy.

20160228_Projekte_135

The OpenSCAD model as well as the Adobe Illustrator (Ai) and PDF files are available as a download from the overview page. Keep in mind that this is one of my first attempts at OpenSCAD, laser cutting and solid CAD modelling alltogether. I’ve tried to keep the CAD model clean and modular but I’m not sure if I succeeded.

20160228_Projekte_100

If you have any questions, suggestions or just your experience with this kind of thing please just post them as comments below. I’m quite new to most of this so I value your feedback and I’m always glad to help if I can.

20160228_Projekte_110

Click here to continue to my next post where  I  talk about the second, analog part of the circuit.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.