Let’s Print a Cat/Pet Feeding Device (Part 4)

This is the fourth part of the series. In this part we insert the insets in the previously printed parts, print the lids and talk about the front panel. If you missed one of the previous parts, visit the overview page to access them.

The Files

You will find all required files for the prints in the GitHub repository:

Git Repository

Insert the Insets

In part two, I explained how to correctly insert the insets into the parts. The instructions you find in this part also apply to the enclosure parts.

I marked all inset locations with red arrows in the following illustrations:

Assembly of the First Enclosure Panels

You may already start to assemble the enclosure. Yet, it may be necessary to disassemble some parts when you add the electronics to the device.

Start by adding part 408A with three screws to part 405A.

Make sure the funnel is aligned and there is no rim where crumbs of the food could be stopped.

Next add the left and right side of the enclosure to the base plate, using two screws from below. Don’t tighten this screws too much, until the whole enclosure is assembled.

Next, place the rotation table platform in the enclosure and insert the vertical axis as shown. Again, don’t tighten the screws too much, you may need to adjust these parts after adding the front and back panel.

Print the Lids and Knobs

Next we print all the lids and knobs. We need four of each part.

Files:
- 4× LR2051-409A.stl
- 4× LR2051-411A.stl
- 4× LR2051-412A.stl
Material: PETG (Galaxy Black)
Layer height:
- Works: 0.2 mm
- Looks better: 0.1 mm
Print bed: Powder coated
Difficulty: Easy
Filament: 36g
Print Duration: ~3h

You can either print all parts as shown, with 0.2mm layer height and you will get a good result. The round top of the knob looks better with 0.1mm layer height, so you can either do two separate prints, or use dynamic layer height in the print.

Assemble the Lids

First, insert an inset into the top part of the knob. Make sure it is flush with the part, otherwise you will get a visible gap.

Next use a long (25-30mm) M3 screw to join the lid and both knob parts.

About the Front Panel

The front panel is designed for the Adafruit 20×4 LCD Display. The opening and dimensions are perfectly designed for it, and sadly it is out of stock in the Adafruit shop. This display has the following dimensions:

Luckily, it seems there are at least two other displays you still can buy, with almost the exact same dimensions. These should fit into the original enclosure:

If you already have a display, with the same dimensions, you can simply print the front panel using the existing STL file. If you like to use no display and no input at all, I also prepared an STL file for this case.

File LR2051-402A.stl is the default geometry for the shown 20×4 character display.
File LR2051-402A-ND.stl is the panel, without any openings and structures for the display.
File LR2051-402A-E.stl is an empty front panel, with no holes and structure.

In this guide, I will assume you use the shown 20×4 character display with the default STL file.

How to Customize the Front Panel

If you like to use any other kind of display, you have several options to customise the font panel.

First, if you own Fusion360, there is the file LR2051-402A.f3d you can modify. In this design is a sketch “user interface element locations” with the basic dimensions for the display opening on the front. A second sketch “display mount” defines the geometry for the display mount.

If you are used to modifying mesh files directly, open file LR2051-402A-ND.stl and add the opening and mounts for your display there. Have a look at the original file, how the opening and mount should look like.

In case you run into problems, or have any questions, please use the comments below or reply to the post on Twitter.

About the Input Section

The input section is designed for a rotary encoder and four LEDs. In one of the next parts, I will provide a generic board you can oder from OSHPark, which will perfectly fit. Also I will provide design files for Autodesk Eagle you can modify for your needs, or use as example to design your own board.

As I will not provide any ready made controller, you may want to design your very own input section. You have the same possibilities as for the display part. So, feel free to redesign this section as you like.

Print the Front Panel

If you have decided on the used components and your front panel prepared, go ahead and print it.

File: LR2051-402A.stl or your custom design.
Material: PETG (Galaxy Black)
Layer height: 0.2 mm
Print bed: Powder coated
Difficulty: Easy

The LED Covers

If you use my design for the input panel, with the four holes for the LEDs, there are the LED covers you have to print.

Files: 4× LR2051-422A.stl
Material: PETG (Transparent)
Layer height:
- Works: 0.2 mm
- Looks better: 0.1 mm
Print bed: Powder coated
Supports: No supports required.
Difficulty: Easy
Filament: ~2g
Print Duration: ~20m

Conclusion

Mechanically, there are only two larger parts missing. The back panel of the enclosure, and the rotation table. In the next part, we will talk about the back panel and the rotation table and print the two last parts.

If you have any questions, missed information, or simply want to provide feedback, feel free to comment below or contact me on Twitter. 😄

Continue to Part 5