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About 3 years ago, I made my own a simple robot arm and published it at: Until now, many people, especially students continued to ask me questions about how to “HOMING” this robot arm. Today I rebuilt this robot arm based on Marlin firmware and added “HOMING” function to the 3 axes of this SCARA plotter. Please watch my video before getting started.

A. Main parts:
- 1pcs x Arduino Mega 2560.
- 1pcs x RAMPS 1.4 Controller. (Or RAMPS 1.6)
- 1pcs x LCD 2004 including ribbon cables and PCB adapter for Ramps 1.4.
- 3pcs x A4988 Stepper Driver Module. (Or 3pcs x DRV8825)
- 2pcs x Stepper Motor NEMA 17.
- 1pcs x CD/DVD ROM for Z axis
- 2pcs x Endstop Mechanical Limit Switches 3D Printer Switch for Arduino RAMPS 1.4.
- 2pcs x Micro Limit Switch for Z axis.
- 2pcs x GT2 Timing Pulley 16 Teeth.
- 2pcs x GT2 Timing Pulley 20 Teeth.
- 2pcs x GT2 Timing Pulley 60/80 Teeth.
- 2pcs x GT2 6mm Closed Timing Belt 200mm.
- 1pcs x GT2 6mm Closed Timing Belt 400mm.
- 2pcs x Round Shaft Diameter 8mm, Length 200mm.
- 1pcs x Round shaft vertical support.
- 4pcs x Horizontal Bearings 8mm.
- 1pcs x V-Slot Aluminium Profile 2020, length 200mm.
- 2pcs x V-Slot Aluminium Profile 2020, length 100mm.
- 4pcs x Aluminum 2020 Corner Bracket.
- 1pcs x Power Supply PSU 12 VDC.
- 1 meters x Two cores Power Cable 1.5/2.5 mm2 for main power supply.
- 2 meters x Cable Spiral Wrap, small size.
- 1 meter x Cabe Tray 20x20.
- Aluminium and wooden plate.
- Some small cable ties, cable spiral wrap, bolts and nuts.

B. PVC pipes and fittings:

- 4pcs x PVC Tee or Cross Ø42mm.
- 1pcs x PVC Tee Ø27mm.
- 1pcs x PVC Reducer Ø42mm to Ø27mm.
- 5pcs x PVC End Cap Ø42mm.”

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