from the bottom and then glued into place (Figure 14).
The instructions tell us to level the bubble while the
enclosure is sitting on a level surface and then glue. I simply
couldn’t find a good way to do this, but it seems to have
seated into the print relatively level to start with. A top
loading design or snap-in fixture could be a useful addition
Now, we can put the Pi
and HAT into the upper
enclosure with four self-tapping screws and nylon
spacers to ensure clearance
between the HAT and Pi. The
screws go in easily, but hold
very well. A lot of trial and
error went into getting the
right fit I’m sure. The Pi is a bit
difficult to get seated into
place, but a few minutes of
wiggling gently and I was able
to get it installed (Figure 15).
The next component to
go on is the tower and Sweep
sensor. The tower uses a self-tapping set screw to register
to the flat of the stepper
motor shaft. The cable for the
Sweep feeds down the
column, and the Sweep itself
is held on by four screws that
go into threaded inserts on
the unit’s base (Figure 16). The cable then goes through a
slot in the top of the base enclosure.
I found it easiest to take the USB adapter off and reinstall it in the base of the unit.
The cable then feeds out through a retainer and plugs
into the Pi’s USB port (Figure 17). Again, attention to detail
like the cable retaining clip was very nice (Figure 18).
Next, we connect the motor and limit switch to the Pi.
The limit switch goes to pin 17 and the 3V rail. The cable to
the 3V rail was a tiny bit short, but bending the pin slightly
made it work. The motor connects to the terminal blocks as
shown in Figure 19.
Figure 17: The USB cable routes out
of the top half of the case and
plugs directly into the Raspberry Pi.
Figure 18: The wire
compartment holds the USB
adapter and the cable is held
in place by a nicely designed
Figure 15: The Raspberry Pi is a snug fit, but with some wiggling
it eventually snapped into place. Holding the standoffs in is a bit
tricky, but the four screws do firmly secure the entire assembly.
Figure 16: Four screws hold the Sweep
scanner onto the vertical
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