The 3D Printed Case

A project log for A Digital Real Time Clock

over-engineering what should be a simple device

zaphodzaphod 05/27/2021 at 20:530 Comments

Electronics need to go in a box so they don't get dusty. When I started this project in 2019 I didn't have a 3D printer and so the case was built out of some aluminum duct work and scrap wood. There are pictures at the bottom of this post.

I spent most of 2020 working on my undergraduate capstone project, and due to the G L O B A L  P A N D E M I C it was all done remotely. In practice this was a good excuse to buy a 3D printer since it was "for school".

Now that I have a 3D printer it makes sense that I would 3D print my electronics enclosures. So that's what I'm doing.

The largest component in the clock is the mains to 3v3 power supply which is a 3v3 meanwell RS-15 series unit. Datasheet [pdf]. As such I designed around the power supply. I like my projects to be easy to work on so I designed the case in 3 parts: a bottom and top cover that bolt together and sandwich a midframe assembly between them. The midframe holds all of the electronics and can be removed from the rest of the case simply by taking the top cover off. Some exploded views of the case:

There is a recess for the USB port on the left side, power input on the rear, the display on the front, and some cooling holes on the bottom. Eventually I'll also add some kind of feet as well so that the power supply gets some airflow.

The design is all done in FreeCAD, and thus far I've been printing in in PLA+ on my Ender 3. Since the top of the midframe contains a lot of interconnect wires that I didn't include in the CAD model I've held off printing the top until the project is more complete since I'm pretty sure that the top cover will require some redesigning.

In its current state the case+electronics looks like this:

The bottom cover:

and some shots of the mostly assembled midframe and electronics: