4. ARFF Manufacturing and Assembly

The wooden exterior box was designed to be laser cut at Texas Inventionworks.  Note the teeth and slots built into the box for ease of assembly:  

The slots on the rear were added to provide clearance for the linkage assemblies as they rotate a full 71 degrees.  The depressions on the side plates would be rastered on the laser cutter to mark the mounting location of the linkage assembly.  The holes on the bottom plate were built in as a method of routing the wires of the stepper motors to the underside of the box.  In order to mount the stepper motor to the linkage while keeping the motor itself secure, a motor mount was custom designed and fabricated using additive manufacturing capabilities provided by Texas Inventionwoks:  

The stepper motor was then fit into this mount as shown below:

The wooden lid of the assembly had a hole cut so that we could glue an acrylic panel to it.  This would allow for the owner to view the inside of the pet feeder.  

We also made a slight design change, where instead of mounting the ultrasonic sensor to a base plate, we instead decided to mount the arduino on the inside of the exterior box, and the ultrasonic sensor to the box itself.  The exterior box would then sit on short plastic legs.