Tail Company EarGear 2 Hat Mount

This is a mount for The Tail Company EarGear 2 that allows the ears to be mounted to a hat with enough structure to support the ears and cover weight.

The SCAD file allows the distance between the ears to be adjusted parametrically, by changing the value of the $separation variable. The SCAD file is dependent on a modified version of hugokernel's OpenSCAD_ServoArms library.

NOTE: This requires disassembly of your EarGear! Do not attempt if you are not comfortable with the process and accept the risks. Damage to your ears could occur that will prevent them from working.

Ear Disassembly

1. Remove the adhesive felt liner from the inside of the plastic headband. This will expose the two servo mount screws and the ear wiring.
2. Separate the case halves of the left ear (containing the control board with the power switch and USB-C port). On some ears, the case is assembled with glue and will have to be carefully pried open with a sharp knife or other tool to break the glue bond on the case halves.
3. Using a permanent marker, mark the servo cable plugged into the port closest to the controller board surface. Take a photo or make whatever notes are required to record the location and orientation of all connections.
4. Unplug power and servo cables. You should be able to maneuver the cables out of their sockets with some angling and care (the servo pin headers can flex). But in order to clear the case edges, carefully removing the hot glue securing the edge of the board may be required. BE SURE NOT TO REMOVE COMPONENTS FROM THE BOARD DOING THIS!
5. Remove the two screws securing the servos to the headband and remove the ears, while freeing the cables from the openings in the band. NOTE: If you have moved the ears at any point in the procedure, make sure to start the ears and allow the ears to home themselves, or they will be misaligned when you assemble them later.
6. You should have now the open left ear with the control board and servo, and the right ear both free of the headband.

Assembling the Mount

1. Place the bottom half of the mount on the inside of the hat and determine its placement. Placement is pretty tricky, go slow, check your work. A fabric pencil to mark location is handy to have.
2. Poke holes for the screws and sandwich the hat material between, securing with six button-head M3 screws and nuts. NOTE: use appropriate length screws for the material thickness so that the screws don't extend past the nuts and interfere with the ears when they turn.
3. Cut out the hat material in the square “windows” next to the servo posts and the circular area underneath the servo screw to pass the cables through.
4. Form the crosspiece to the curve of the hat by heating with a hair dryer (don't use a heat gun, it will get to hot too fast) on high for a handful of seconds. It won't take long - just watch carefully for the sheen of the plastic to change and the moment it starts to sag (don't wait or it will warp!), remove heat and put the hat on and press to form it to the inside curve. CAUTION: while it shouldn't be hot enough to cause burns or discomfort, the plastic will be hot - take care to protect your head from the heat.
5. Take the left ear (with the long battery and servo cable) and place it on the marked side of the mount aligning it parallel with the mount in the correct orientation (curved side to the outside edge).
6. Route the cables along the bottom edge channel in the mount and back up through the hole. Leave a little slack in the area where the wires turn to go through the large rectangular hole up into the ears, to allow the ears to fully rotate. You may wish to use tape to hold the wires in place and keep them in the channel.
7. If you removed the hot glue securing the control board, replace it. Do not over-apply glue, you really want to glue the board edge, not the components on it.
8. Attach the right ear servo half to the mount, again being careful not to disturb the orientation.
9. Reattach the servo and battery wires to the control board.
10. Reassemble the case halves. A small amount of cyanoacrylate glue (e.g. “Super Glue”) in several spots around the perimeter (in case you want to open it again) is completely sufficient. Clamp with rubber band or other method and let the glue set.
11. Test the ears. Start them and let them home. Check function with the app. If the ears are slightly home misaligned, reset their positions.
12. Replace the M2.5 servo screws with 14mm length screws and tighten finger-tight, excessive force is not necessary.