I was looking for a way to mount a monitor and Raspberry PI into my car. Nothing online seem to fit my situation so I came up with this 3D printed mount. It uses a 3D printed base, various hardware (screws, standoffs, etc.) and a purchased tablet mount that works in a cup holder. I'm very happy with how it turned out.

Step 1: Tools/Materials

Tools

Allen wrench
Adjustable wrench

Materials

3D Print (x1)
Tablet Mount
Monitor
Raspberry Pi
Power Supply
Cables (HDMI, Power, OBD)
Raspberry Pi Mount Hardware
- Hex Standoff, Female - M2.5x19 (x4)
- Washer, Flat - M2.5 (x8)
- Washer, Lock - M2.5 (x8)
- Screw - M2.5x10 (x8)
Monitor Mount Hardware
- Screw - M2.5x20 (x2)
- Washer, Flat - M2.5 (x8)
- Lock nut - M2.5 (x4)

Step 2: CAD

I already had the monitor and Raspberry PI. From there, I tossed around different mounting options. Using a purchased tablet mount (cup holder version), I worked out the concept and dimensions in CAD. Once it looked good, I sent the main piece (shown in copper color) to the 3D printer.

Step 3: STL File and Drawing

This step includes the drawing and the STL file for 3D printing. I suggest making it from ABS or another high temperature material since the interior of a car will exceed the PLA temperature limit. All holes are oversized to guarantee fit with the M2.5 hardware.

Mounting_plate.stl
Download View in 3D

Step 4: Assembly - Step 1

With the 3D print in hand, I started the assembly. I installed the standoffs for the Raspberry Pi first since these are only accessible prior to monitor installation.

Stackup:

M2.5 Screw
M2.5 Lock washer
M2.5 Flat washer
3D Plate
M2.5 Standoff

Step 5: Assembly - Step 2

Next, I screwed the Raspberry Pi to the standoffs.

Stackup:

Raspberry Pi
M2.5 Flat Washer
M2.5 Lock Washer
M2.5 Screw

Step 6: Assembly - Step 3

The monitor was then attached to the other side with bolts and nuts.

Stackup:

M2.5 Screw
M2.5 Flat Washer
Monitor
3D plate
M2.5 Flat
M2.5 Lock Nut

Step 7: Cable Hookup

These connections were pretty straightforward. The cables shown were longer than needed. I did include a hole (not shown) for cable clamp on the side away from the Raspberry Pi.

Step 8: Mounting

These pictures show the mount installed in a extra cup holder. Note the tight spiral in the line. This was required for the tight space in my car.

Step 9: Installation

These pictures show the mount installed in my car - Acura RSX.

Not shown in these pictures is the OBD-2 to USB cable. This was run from the Pi to the OBD-2 connector behind the center console. The power was taken from the 12V power socket and run through a converter to the power supply.

As you can see, I don't have much room in my car but I'm happy with how it fit. The same mounting concept should work better in a full size car or truck.