The enclosure for the Voice It is entirely 3D-Printed. The enclosure can be printed out of PLA but you’re welcome to choose an engineering-grade filament if you want to make it “indestructible”.
The Voice It enclosure is comprised of four 3D-printed parts:
- an enclosure top
- an enclosure base
- an optional RFID card bracket
- an optional wire clip
You downloaded STL files for these components when you downloaded the Voice It software.
The STL files can be found in the “enclosure STLs” folder:
Each of the folders contains two files:
So which folder should you get your enclosure STL files from? That depends on the kind of Voice It you want to build. Each folder name has two parts, separated by a comma. The first part is tied to whether you want your Voice It to be triggered by an RFID tag, a QR code, or both. The second part is tied to whether you want to have the audio file sounded through an internal speaker, an external speaker (or set of headphones), or both.
If you include an internal speaker, you’ll also need to to print a “wire clip”. If you will use RFID tags, you need to print an “RFID bracket”. Finally, if you will be using QR codes you need to print both a “QR module enclosure face” and a “QR module enclosure back”.
Note that all of the enclosure bottom STL files that have been provided are designed to accommodate the Adafruit 328 battery. If you are going to use the Adafruit 2011 battery, you will need to use the Voice It designer program (Voice_It.scad), select “Adafruit 2011” as the “battery type”, and then render and generate the STL file for the enclosure bottom.
If you’re interested in designing your own enclosures using the Voice_It.scad designer program, you can find instructions here.
Finally, don’t include supports when slicing the enclosure parts. All parts were designed so as not to need them and they can interfere with the sacrificial layers built into the reset switch mount and corner bolt holes.
Printing the Enclosure Top
As part of the preparation of the enclosure, you’ll need to insert (4) #6-32 hex nuts in each corner of the enclosure top.
Hint: The top and bottom enclosure pieces are both rather large and both have a solid, rectangular, first few layers. 3D-printing these kind of objects can be challenging because they can tend to warp a little at their corners. Warping won’t affect the functioning of the Voice It but it can be visually less pleasing than having a totally flat surface. This is particularly an issue for the enclosure top because a warped surface will be visible. You can mitigate against warping very effectively by applying a layer of glue stick to the build plate before printing.
The top and bottom of the enclosure are held together by four machine screws and four nuts in the corners of the enclosure. There are two options for installing the nuts. The MUCH preferred way is to embed the four nuts during the printing process. However, you may have difficulty pausing the print long enough to embed the nuts – or you simply may forget. It takes a long time to print the top of the enclosure and rather than force you to print it again, you can insert the nuts through an access slot instead:
Embedded nuts
When printing the enclosure top you will need to insert four #6-32 nuts in each corner at a z-height of approximately 30 mm.
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It can be difficult to position the nuts properly in the slots. They tend to fall in at an angle and then be difficult to reposition. Here’s a technique that may work for you to make positioning the nuts a bit easier.
Before the printer pauses to insert the nuts, put the nuts on the tips of the four (or five if you’re extra cautious) machine screws you’ll be using later during assembly. When the printer is paused for inserting the nuts, you can use the screws to push them into position easily. Then turn the screw counter clockwise to free the screw from the nut. Repeat until all four nuts are in place. You may not be able to use this technique if the print head is over or in the way of one of the corner slots.
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The video below shows the print pausing and using some bolts to insert the nuts.
Within a couple more layers, the printer will begin to print a fine layer of filament across the slots:
This layer, called a “sacrificial bridge”, will serve as a foundation for printing the continuing hole for the machine screw. Later, when assembling the enclosure, you’ll push through (i.e., sacrifice) this layer with the machine screw. You’ll be able to feel the resistance when you do. [This sacrificial layer is similar to the one in the enclosure base that you’ll use a scissors to clean out before you insert the momentary switch.]
You’ll see a second sacrificial layer for the slide-in nut option.
Inserted nuts
The enclosure top also allows you to slide-in the nuts just prior to bringing the two parts together at the end of the assembly. But don’t wait until then. It’s much easier to get the nuts into place without wires in the way. Do it as soon as you stop printing the enclosure top. Depending on your printer the slot may hold the nuts firmly or allow them to slip back out. That can be frustrating when you’re turning the top over for the final assembly.
The following video will demonstrate one way to align the nuts and get them to stay in place – at least long enough for assembling the enclosure.