The 3D printed parts are a mashup of a remix! I started with this Smart light switch with a servo by Thingiverse user pulsar123 (which is a remix of Servo Switch Plate Mount by carjo3000).
I combined it with the excellent Mount for Crickit by the Ruiz Brothers.
I also modeled a cover for the Cricket that can be screwed in place once everything is set up.
Download STL Model Files
You'll need to download these three STL files to 3D print the mount, servo arm, and cover. Click the button below to download the files.
Slicing in CURA
These settings were used to print the three pieces (not all at once as shown here!):
- 0.4mm Nozzle
- 0.2mm Layer Height
- 0.38 Line Width
- 2 Wall line count
- 70mm/s printing speed
- 10% infill
Prep the Feather and Crickit
Next, solder the plain male header pins into place on the Feather so that it can be mounted onto the Crickit. You can follow this guide for instructions.
Then, mount the Feather onto the Crickit's header sockets.
Threaded Inserts
In order to screw the Crickit in place, as well as the standoffs for the cover, we'll add heat-set threaded inserts to the bracket.
Place the tapered smaller end of an insert into an opening and then use the soldering iron to heat and press the brass insert into place.
Mount the Crickit into the Bracket
Use four of the M2.5 x 6mm screws in to fasten the Crickit to the top two and bottom two threaded inserts.
Then, screw in four stacks of paired M-F standoffs. Each pair will consist of a 6mm and 12mm standoff to get the proper clearance needed for the cover.
Servo Arm
The servo arm would have a hard time turning the switch on it's own, so we'll add the 3D printed extension. It has a curved guide with stops that allow it to flip the traditional light switch easily.
Fit the 3D printed arm over the small servo horn supplied with the micro servo.
Place the horn onto the spline shaft of the servo, then turn it to find the range of motion.
Turn the servo to roughly its middle position and then remove and re-seat the arm so it is oriented as shown so that it will be able to flip the switch when mounted.
Use the supplied screw to secure the arm and horn to the shaft.
Secure the servo to the mount with the two small screws.
Servo Connection
The servo motor uses three pins -- power, ground, and signal. Plug the servo header into the Crickit Servo 1 port with the yellow signal wire facing out as shown.
Next, we'll program the Feather using CircuitPython and test it before mounting it to the switch plate.
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