Bill of Materials

Complete list of parts needed to build a Mini-Arm.

Electronics

Component

Qty

Price (USD)

Link

Raspberry Pi Pico 2

1

$5

Adafruit

MG90S Micro Servo

6

$18

Amazon

SG90 Micro Servo (gripper)

1

$3

Amazon

PCA9685 Servo Driver

1

$6

Amazon

USB-C Cable

1

$5

Any

Jumper Wires (M-F)

20

$4

Amazon

5V 3A Power Supply

1

$8

Amazon

Electronics Subtotal: ~$49

Hardware

Component

Qty

Price (USD)

Notes

M2 x 8mm Screws

20

$3

Pan head

M2 x 12mm Screws

10

$2

Pan head

M2 Nuts

30

$2

M3 x 10mm Screws

10

$2

Pan head

M3 Nuts

10

$2

608 Bearings (8x22x7mm)

4

$5

For smooth rotation

Rubber Feet

4

$2

Anti-slip base

Hardware Subtotal: ~$18

3D Printed Parts

All parts can be printed on a standard FDM printer.

Part

Qty

Material

Time

Base

1

PLA/PETG

3h

Shoulder

1

PLA/PETG

2h

Upper Arm

1

PLA/PETG

2h

Forearm

1

PLA/PETG

1.5h

Wrist

1

PLA/PETG

1h

Gripper Base

1

PLA/PETG

0.5h

Gripper Fingers

2

PLA/PETG

0.5h

Servo Mounts

6

PLA/PETG

1h

Electronics Mount

1

PLA/PETG

1h

3D Printing: ~$15 (material cost) / ~12 hours print time

Print settings: - Layer height: 0.2mm - Infill: 20% - Supports: Yes (for some parts) - Material: PLA recommended, PETG for durability

Download STL files from assets/stl/ or Printables.

Optional Upgrades

Upgrade

Price

Benefit

MG996R Servos

$30

Higher torque, larger payload

Slip Ring

$8

Continuous base rotation

Camera Mount + USB Camera

$15

Vision applications

Force Sensor (gripper)

$10

Grasp force feedback

Limit Switches

$5

Precise homing

Total Cost Summary

Basic Build

~$82

Electronics

$49

Hardware

$18

3D Printing (material)

$15

With All Upgrades

~$150

Next Steps