Here is my take on an external stepper driver and Octoprint/OctoPi housing for the Tevo Little Monster.
I followed the same approach as e.g. dot_bob and bodog here on Thingiverse and designed a box which will sit on top of the existing Tevo Little Monster controller casing to provide active cooling to the TMC2100 Silent Step Stick drivers through the existing cooling fan inside the TLM controller box.
In order to house all the equipment I wanted to stuff into the box (and to make the front panel seamless) I also made the box bigger to take up the full real estate on top of the stock controller housing and design a modular front plate to provide different installation choices.
At full capacity (with some room to spare) the following equipment can be comfortably housed inside the enclosure:
- 4x TMC2100 Silent Step Stick external stepper drivers
- 2x Power relays (e.g. for LED lighting or even for TLM mains power control)
- 1x DCDC converter with display
- 1x Raspberry Pi 3, 3B or 3B+ (Pi 2 should also fit)
- 2x Power distribution PCB to reduce the cable mess
In addition it is possible to breakout one (or more) Pi USB connectors internally to provide a clean USB connection between OctoPi and MKS SBase board internally (note: soldering required)
Following files are included in the package:
Main Enclosure - 3D Printable files (no raft, support required):
- Enclosure_Top.stl -> top plate with all the mounting points for stepper drivers, Pi and Relays
- Enclosure_Bottom.stl -> bottom box to be mounted on top of the TLM enclosure with the help of the existing fan screws (stock screws are long enough)
4 Face Plate options depending on the equipment you want to install – 3D Printable (no raft, support required):
- Face Plate_Pi & DCDC.stl -> full feature face plate with cut outs for both Raspberry Pi and DCDC converter display
- Face Plate_Pi half USB & DCDC.stl -> same as Face Plate_Pi & DCDC above but with one of the Pi USB slots blocked off in case you want to route it internally (prevents you from accidentally plugging stuff into the USB port)
- Face Plate_Pi half USB only.stl -> Face plate without the DCDC Display cutout and with one of the Pi USB slots blocked off
- Face Plate_Pi only.stl -> Face plate without DCDC Display cutout and all Pi USB connectors accessible
3 Face Plate options depending on the equipment you want to install – Files for CNC/Laser cutter
For those with access to a CNC mill or a laser cutter you can cut the face plate out of 2.5mm acrylic to get uniform enclosure front together with the existing TLM enclose face plate.
Note: The files are mirrored so that the Octoprint logo can be engraved from the back instead of the front
- Face_Pi full.dxf -> face plate with all Pi USB ports exposed
- Face_Pi half USB.dxf -> one Pi USB port blocked off in case you want to route it internally (prevents you from accidentally plugging stuff into the USB port)
- Face_no Pi.dxf -> just the Octoprint logo with no cutouts for the Pi
- All holes are for M3 screws. Using a M3 tap after printing to pre cut the threads is recommended
- Internal USB to USB connections require you to solder a USB extension cable to both the MKS SBase and the Pi USB header pins on the bottom of each board. Drop a note here if you would like the pinpout and I will be happy to provide it.
I suggest to connect all 4 wired (5V, GND, Data – and Data +) on the sBase to a USB cable with female connector and connect only GND, Data+, Data- to a male USB cable on the Pi. This will allow you to easily disconnect the Pi and Sbase from each other in case you require access to the sBase USB port (only one can be connected at the same time)
- To reduce wiring mess I recommend to install a project board inside the bottom enclosure and use it as simple power rail for 24, 5V and GND. The bottom enclosure has 4 “rails” on each side to allow you to mount the board
- To reduce cabling mess between the TLM enclosure and the external driver box only route one 24V power cable up and use the power rail as mentioned above to break out 24 v and 5v from the DCDC converter
- Rewire your case fan from the cooling fan connectors to the sBase 24v main connector so it is always on when the machine is powered. This will ensure constant cooling even if the printer is not printing (e.g. after G28 the drivers will still be powered and hold the head in place and require cooling even if the hot end is not in operation)
Links to equipment used:
As there are now many variants incl. CNC router files for the faceplates I have only uploaded one 3D Printable variant with the SD card opening. If you need a different version please drop a note in the comments and I will upload the file for you.
1 additional Face Plate added:
Face Plate_Pi & DCDC & SD.stl -> full feature face plate with cut outs for Raspberry Pi, DCDC converter display and SD Card extension