Tutorial #3 - Power unit assembly - Lacina.dev Home - LACINA.DEV

Tutorial #3 - Power unit assembly

I don't want to delay you with long readings, so I'll use pictures a lot and point you out important things. It's easy, let's get to it. If necessary, you can watch the video. You will find the whole assembly procedure there.

Assembly takes about 55 minutes.

At this tutorial we will assemble Power unit. It's rear part of the Vitulus robot that contain battery, power module, etc.

First, make sure you have all the necessary parts.

Necessary parts
DSC02685.JPG Necessary parts

Part list

  • Printed parts - download STL files Power unit
  • Printed parts - download STL files Supports
  • 2pcs - Assembled Wheel unit ( Tutorial #1 )
  • 19pcs - M3x16 screw
  • 2pcs - M3x30 screw
  • 25pcs - M3x1.6 square nut
  • 8pcs - M3x25 screw
  • 20pcs - 3.2 x 9 mm pad
  • 16pcs - M3 nut self-lock PA
  • 4pcs - M3x8 nut (Hex stand-off)
  • 16pcs - 3.2 mm serrated lock washer
  • 2pcs - M3x215 mm threaded rod
  • 6pcs - M3x425 mm threaded rod
  • 1pce - XT60 female
  • 1pce - XT60 PCB - download EasyEda source files
  • 30 cm - 16 AWG two lines wire
  • 1pce - Emergency button 10 A
  • 1pce - Power switch 16 mm with LED
  • 1pce - fan Noctua NF-A4x10 5V PWM Manufacturer
  • 1pce - 25 mm 3M Dual Lock reclosable fastener


Assemble the wheel units and Power unit body. I don't mention this in details. It's the same as assembly of Main unit support in tutorial nr. 2. Please follow the steps 4, 5, 6 in tutorial nr. 2.

Wheel units and body assembled
DSC02686.JPG Rear view
DSC02687.JPG Top view
DSC02688.JPG Front view
DSC02689.JPG Bottom view


Assemble the cover nuts. Follow the pictures and insert the M3 squared nuts into holes. Once the nuts are inserted, fix them by silicone sealant (or use something similar).

Cover nuts
DSC02692.JPG Without nuts
DSC02692.JPG Nuts placement
DSC02694.JPG Insert the nuts and fix them by silicone sealant.


Follow the images and stick the 25 mm 3M Dual Lock reclosable fastener for battery and USB hub.

Stick the fasteners
DSC02695.JPG Use 3M Dual Lock 25 mm
DSC02697.JPG For battery
DSC02696.JPG For USB hub


Assemble tail with power connector. Solder XT60 connector and wires into the PCB. Use heat shrink tubing on contacts for isolation. Insert M3 squared nuts into the tail. Insert the connector into the plug and fix it by pad. Then put the plug into the tail body and fix it by two M3x30 screws.

Tail with power connector
DSC02698.JPG Required parts for connector
DSC02700.JPG Assembled connector
DSC02701.JPG Required parts for tail
DSC02702.JPG Insert the M3 squared nuts
DSC02703.JPG Insert connector into the tail plug
DSC02705.JPG Fix the connector by pad
DSC02707.JPG Put the plug into the tail
DSC02708.JPG Fix the plug by M3x30 screws


Assemble the tail into the Power unit. Follow the images and insert the M3 squared nuts into the holes. Insert the cable thru the hole and put the tail at the Power unit body. Use the four pieces of M3x16 screws to fix the tail.

Assemble the tail into the Power unit
DSC02709.JPG Nuts placement
DSC02711.JPG Insert the M3 squared nuts
DSC02712.JPG Insert the cable thru the hole and put the tail at the body
DSC02713.JPG Fix it by four M3x16 screws


Assembly Noctua NF-A4x10 5V PWM fan into the Power unit body. Follow the images bellow for fan placement and orientation. Use the four M3x25 screws, big washers and self lock nuts to fit the fan. Tighten gently.

Fan assembly
DSC02714.JPG Required parts
DSC02716.JPG Fan placement
DSC02717.JPG Tighten gently
DSC02718.JPG Assembled from inside
DSC02719.JPG Assembled from outside


Follow the images and mount the switches. On emergency switch use printed pad. For the cover use M3x16 screws. For the letters on the top cover use super glue to fit them on their places.

Switches and top cover assembly
DSC02720.JPG Required parts
DSC02721.JPG Emergency switch assembled
DSC02722.JPG Power switch assembled
DSC02723.JPG Put on the top cover
DSC02725.JPG Fit the cover by screws

Power unit assembly is finished :)

Power unit finished
DSC02730.JPG Front view
DSC02729.JPG Bottom view
DSC02728.JPG Rear view
DSC02725.JPG Top view