Robotic Arm - 1

RA-1

Overview

As a high school student, I love tinkering with robotics, but I quickly realized that almost every desktop robotic arm design online falls into one of two traps: they are either expensive to source hardware for, or the budget-friendly options are completely flimsy and vibrate like crazy.

I designed this robotic arm from scratch to bridge that gap. My goal was to maximize structural rigidity while keeping the entire build strictly under an ultra-affordable $75 USD budget (including all 3D printing filament, electronics, bearings, and hardware). 

Specifications & Dimensions

• Base Footprint: 140mm x 140mm
• Absolute Standing Height: 310mm
• Total Build Cost: ~$75 USD

Hardware & Bill of Materials (BOM)

To make sourcing easy, here is the exact hardware manifest used to design the tolerances for this model.

Electronics

• 1x ESP32 Development Board 
• 1x PCA9685 16-Channel 12-Bit PWM Servo Driver (I2C Interface)
• 4x MG996R High-Torque Digital Servos
• 1x 20KG High-Torque Waterproof Servo (Used for the main high-load joint)
• 1x SG90 Micro Servo

Mechanical Hardware

• Deep Groove Ball Bearings: 607zz (Provides smooth, rigid, wiggle-free joints)
• 12x 8x2mm Magnets (Integrated into the design for quick-snap access panels/toolless ends)
• Brass Threaded Inserts: Used across all major joints for secure, repeatable plastic-to-metal connections.
• Miscellaneous: Standard M3 screws, jumper wires, and an external 5V power supply suited to drive the servos.

Printing

Certain parts should be printed out of PETG as they require the strcutural benefits of the polymer, e.g the gears and any servo hats, however other parts printed out of PETG were purely cosmetic.

Note: This model is far from perfect and may need some tickering to be fully functional.

I also have planes to add attachments to the end of the robotic arm, thus the hole for cable routing.