EZ Manipulator with instruction and code

NOTES / WHAT TO EXPECT
I tested the full-size version, but the SG90 servos + 28BYJ-48 stepper can’t handle the torque for heavier loads.
The lighter version works well and can move very light loads (e.g., a pen).

The model itself is very smart and well-designed — the main limitation is motor strength.

BOM (BILL OF MATERIALS)

3D PRINTED PARTS
- Only 1 printed plate is needed (use the provided print profile).

ELECTRONICS
- Arduino Uno + breadboard
- 2x SG90 servos (MG90S recommended for better torque)
- 1x 28BYJ-48 stepper motor + ULN2003 driver
- Power supply: 6V recommended
 (5V works, but may struggle/stall at some angles or higher load)

INPUTS / SWITCHES
- 3x push buttons:
 - 2x used as limit switches for stepper homing (MIN/MAX)
 - 1x used for gripper toggle
- 2x potentiometers (or any rotary input you prefer)

HARDWARE (SCREWS)
- 2x M3 long screws + nuts
- 4x M2 screws (usually included with SG90)

ASSEMBLY NOTES
- After printing, check the last 2 pictures for the stepper motor assembly.
- The 4th picture shows the limit switch mounting for the stepper motor.
 These are used for homing and prevent the stepper from over-travelling.

HOW IT WORKS (FIRMWARE)
- On startup, the robot performs a homing test:
 - Moves to MIN and MAX
 - Presses each limit switch twice to confirm reliability
- After homing, you can start controlling it normally.
- If you see small shaking/jitter, you can tune values in the code to smooth the input readings.

MOTOR / TORQUE TIPS (OPTIONAL UPGRADES)
If you want more torque and stability:
- Swap SG90 -> MG90S (metal gear) or stronger servos if your build allows
- Use a solid 6V supply with enough current (important when servo load increases)

CODE
I’ve included working code. It runs well on my setup but may need small tuning depending on your power supply,
servo quality, and friction/tolerances.

If you need help improving smoothness, speed, or torque handling, feel free to comment — happy to help.
Thanks so much for reading! <3