Total time spent thus far: 103h

May 25-26: Initial Concept and Design

• Created idea
• Pitched concept
• Developed rough Bill of Materials (BOM)
• Total time spent: 4h

May 26-28: Arm Assembly and Design Refinements

• Finished first part of the arm
• Nearly completed second part
• Redesigned bearing holders (original design required impractical assembly)
• Identified needed PCB components:
  • 4 × 3-pin connectors for Servos
  • 1 × 4-pin connector for stepper
  • 1 × 2-pin connector for PSU
  • 3 × MG996R servos
  • M3.5 screws
  • Nema23 23HS5628 stepper + TB6600 Controller
  • SG90 servo
  • LM2596 voltage regulator (for ESP32 compatibility)
  • PSU: AliExpress link
  • Rotary encoder
• TODO:
  • Finish second arm
  • Complete claw mechanism
  • Finalize bottom part
  • Design camera mount

Total time spent: 16h

May 29: Structural Completion and PCB Design

• Finished all arms + claw assembly
• Improved aesthetic design
• Designed PCB (significant time spent on hole placement)
• Created stepper motor base connection with tight-tolerance square insert
• Current progress: ~60%
• TODO:
  • Complete base assembly
  • Fix 3D printed inserts
  • Finalize BOM
  • Begin coding
    

- Total time spent: 6h

May 30 - June 1: Component Updates and PCB Revision

• Arm improvements:
  • Added screw mounts to arm holders
  • Designed printable nuts for assembly
  • Created side components
• Major PCB changes:
  • Switched ESP32 → Raspberry Pi Zero W (better camera streaming)
  • Significant time spent updating PCB layout/screw holes
• TODO:
  • Design camera mount
  • Convert to wall-plug PSU
  • Add/remove rotary encoder based on space
  • Update connectors: 2-pin → PSU pins, 4-pin → 6-pin
  • Find placement for TB6600 Controller
    

- Total time spent: 10h

June 2: Power System and Controller Updates

• Implemented changes:
  • Converted to wall-plug PSU
  • Added second rotary encoder
  • Updated connectors: 2-pin → PSU, 4-pin → 6-pin
  • Replaced TB6600 with space-saving TMC2208 controller
• TODO:
  • Finalize camera mounting solution
  • Complete official BOM
  • Start coding base functionality
    

• Total time spent: 4h

June 2: Github Stuff

• Created Journal.md
• Finished BOM
• TODO:
  • Add Camera to BOM
  • Finalize camera mounting solution
  • Start coding base functionality
  • Start coding VR → Arm Pose in Unity
• Total time spent: 3h

June 2-4: Coding

• Added rotary encoder support
  • Encoder 1 → controls Joint 1
  • Encoder 2 → controls Joint 2
  • Encoder 3 → controls the claw
  • Encoder 4 → controls base (stepper/rotation)
• Implemented inverse kinematics with safety checks
  • Enforces ±90° range from vertical (coded as 90°)
  • Restricts x ∈ [-5.5, 5.5] if y ≥ -2 cm
• Added movement validation system
  • Only moves to reachable coordinates within the arm’s physical limits
  • Displays an error if the point is unreachable
• New command features
  • Supports input like x:5,y:8,z:-2
  • stop command halts all motors immediately
• Maintains stable claw orientation (always facing downward)
• TODO:
  • Finalize camera mounting solution
  • Start coding VR → Arm Pose in Unity Total time spent: 10h

June 4-10: Coding for Pi Zero 2 W to Unity VR

• Ported legacy code to Pico SDK environment
  
• Implemented hardware abstraction layer for:
  
  • Servo/stepper motor control
    
  • Rotary encoder feedback
    
• Verified all hardware functionality
• Built a lightweight TCP server using lwIP
• Added WebSocket support for real-time control
  
• Key endpoints:
  | Endpoint | Function |
  |----------|----------|
  | /move | Coordinate-based arm movement |
  | /direct| Raw servo control |
  | /encoders | Live position feedback |
  | /camera | MJPEG video stream (10 FPS) |
• Unity Features:
  
  • Controller-triggered calibration
    
  • 1:1 movement mapping (VR → Physical Arm)
    
  • Real-time camera display
    
  • Connection status UI
  • TODO:
  • Find out where to put the camera :sob:
    

Total time spent: 20h

Aug 1-20: Hardware Building, Testing and Debugging

- Failures & Issues - Burned 1 × Raspberry Pi Zero 2 W (likely due to incorrect LM2596 calibration)
- 1 PCB failed due to soldering issues (not design-related)
- Accidentally ordered 360° continuous rotation servos instead of 180° positional ones
- Stripped the internal gear of TWO 180 ° servo during torque testing
- Original 3D-printed gears failed under load, requiring redesign

• Fixes & Improvements

  • Learned an important tip: always calibrate the LM2596 before powering sensitive boards
    
  • Fully soldered all working boards and connectors
    
  • Updated firmware with expanded debugging tools (serial logs, error states, power monitoring)
    
  • 3D printed replacement parts to strengthen gear assemblies
    

• Integration & Results

  • Ran the PCB successfully after assembly
    
  • Verified stable communication between Raspberry Pi and motor drivers
    
  • Completed end-to-end integration of PCBs, motors, and encoders
    
  • System reached the stage of a stable working prototype
    
  • Project will be on hold until I get another 180-degree servo to implement VR support

Total time spent: 30h