Kindle Fire HD 8 Wall Mount

Overview

In a tale as old as time, I needed to replace my wired alarm system.  The ancient system has hardwired sensors (yay!) and a keypad.  Replacing that with Konnected seems to be the standard DIY solution.   However, there are no keypads for Konnected, and instead you normally use wall mounted tablets.

I had an Kindle Fire HD 8 I wanted to use, because the wall I'm mounting it on is reasonably narrow.  You can see in the photo, it is only slightly smaller than the space it fits into.  A further complicating problem is that I want to center it on the wall, but the power wires from the alarm system come in on the far right.  Here were the design constraints I had/put on myself:

• Symmetry.  I didn't want one side/bottom/top thicker than the others. 

• Clean look with no visible connections

• Easy ability to service if (ok, when) some problem comes along 

• Ability to center the tablet on the wall and have some height adjustment

Files

My general plan is not to make my fame and fortune from printables models, so I normally include the Fusion360 files (unless I'm embarrassed by them, and sometimes even then). So, I've provided a single STL and then the Fusion file.  If you need something specific, I can't promise I'll be responsive, but ask and I'll try.

• STL with the box centered

• Fusion360 file that you can modify if you need to move it around

Supplies needed

• Old work single gang electrical box

• 12V to 5V USB-C converter with right angle connector

• Circular magnets

• Various screws

• Level

Parameters

There should only be 3 parameters you might need to change

The two "user_box_[X]_offset" control how far right and up the electrical box mounting hole is.  Fusion gets unhappy if I have an offset in the drawing, and then try to set it to 0, so these are set to incredibly small numbers so that it's functionally center.

user_magnet_thickness is a function of how thick the magnets are.  This controls how deep the holes are so that they work.  The magnets I linked to measure out at 2.75 mm per, so I round up. 

Note:  When you use magnets to get things to stick together, it's really satisfying, but they're terrible for shear forces.  So this design has the magnets in the frame sunk in by magnet_offset distance and the ones in the cover "proud" by that same amount so that they hold it closed well, but there is a mechanical portion too.

Examples

Here is what the frame looks like when your box is perfectly centered on where you want to mount the tablet:

But my box was in the wall, 74 mm to the right, so here is what mine looked like:

Other Notes

• It's showing a Home Assistant LCARDS dashboard so the whole thing is Star Trek themed.  Yes it's pretty cool.  Yes, it was a total PITA to configure and get setup. 

• Yes, that temperature is accurate.  Don't come visit Phoenix in the summer.