fischertechnik compatible case for brushed motor ESC

Building this model involves some soldering of wires and desoldering/resoldering of components and wires on the ESC module. Below you will find documentation on the modifications I made to make it work. If you decide to go along with it, you do so based on your own judgement and at your own risk of voiding any warranties and possibily damaging some parts. 

Printing

Both upper and lower case parts can be printed without supports with their outer surface touching the bed.

Recommended print settings: 0.4mm nozzle, 0.1mm layer height, 4 perimeters, 8 bottom and top layers.

The bottom half is available in two variants, with and without 0 and I (off/on) markings.

Feedback, remixes and pictures of your makes are very welcome. 

Required Parts

• RC-ESC 30A brush-motor-speed-controller with brake, sold on various sites without brand or model name, see for example here
• Pololu #2811 reverse voltage protection board
• Small sliding switch for breadboards, body size 8.7 x 3.8 x 3,5 mm³ (e.g. BB-Switch-3P from berrybase) 
• 4x fischertechnik “Bundhülse” 6.5 mm 
• 7x2 two-row pin headers 2.54 mm
• 6x M2x12 countersunk bolts, either raised or flat (ISO 7046 or ISO 7047)
• prototyping PCB strip, roughly 15x2 holes or 36 x 5.1 mm²
• 3-pole 1:1 cable with DuPont connectors to connect the ESC to the receiver (aka servo-cable)

Interface Board Assembly

• insert pin header into PCB strip for mechanical support (no soldering at this point!)
• push “Bundhülsen” between 2x2 pins of the pinheader for a tight fit :
  
• solder “Bundhülsen" to the pins, remove from PCB strip
• cut pin header to get two pairs of “Bundhülsen” assemblies and a 3x2 pin header
• solder these to the PCB strip, making sure the fronts of the “Bundhülsen” are flush to each other:
  
  
• file or sand down the sides of the PCB strip so that the two covers can close without a gap
• solder the switch to the lower row of 3 pins so that the upper rows can still receive a DuPond plug:
  

Electronics assembly

• Remove the transparent shrink wrap from the ESC module
• The sliding switch needs to be repositioned to face the other way round, from this configuration:
  
  to this configuration:
  
• Wiring diagram:
  
• Before soldering wires to the interface, some of the longer pins can be clipped, e.g. the ones marked in red:
   
• The casing provides ample space for the cables but depending on which side of the PCB the cables are attached to, some of the wires may need to be repositioned.
  
• Soldering should not be done inside the casing to not melt the plastic, but frequently checking if the assembly still fits is a good idea. The ESC PCB can be positioned to either have the break switch (the one repositioned earlier) stick out or be recessed like here:
  

Before closing the case, now is a good time to perform a functional test, making sure to also switch on the pololu board.