17. Applications and Implications, Project Development
1. What will it do?
My final project is a computer vision-based robotic arm designed to physically track a person in space using an OpenMV H7 camera. The robotic arm has two servo-driven degrees of freedom, these being height and extension, and one stepper-driven rotational axis, all coordinated via a custom PCB based on the XIAO RP2040. The camera identifies a person and sends their positional data to the microcontroller, which then adjusts the motor outputs to maintain focus on the subject. The goal is to create a semi-autonomous tracking system for applications in surveillance, interaction, and documentation.
2. Who has done what beforehand?
My primary inspiration for the concept and control logic comes from the Jet Max project, which also features vision-based object tracking with articulated movement. For the mechanical structure, I drew on principles from parallelogram mechanisms, a proven design used to stabilize the end effector of robotic arms regardless of movement in other joints. These sources helped shape the design philosophy and system logic behind my own version.
3. What will I design?
- Complete structure of the articulated robotic arm and it's base
- A custom RP2040-based PCB to interface with motors and the camera
- Software for real-time visual tracking and motion control
4. What materials and components will be used?
5. Where will they come from?
6. How much will they cost?
This is the current Bill Of Materials:
Mechanical Components
| Item | Details | Quantity | Unit Price | Source / Link |
|---|---|---|---|---|
| PLA Filament | Black PLA | ~1.6 kg | $23.50 per kg | Link |
| Axial Ball Bearing | 78mm OD, 40mm ID, 26mm H | 1 | $5.68 | Link |
| Nema 17 planetary gearbox | 10:1 Ratio | 1 | $11.00 | Link |
| M3 Screws & Nuts | Mixed lengths | 10 | N/A | N/A |
| M5 Screws | 12mm | 9 | N/A | N/A |
Electronic Components (External to PCB)
| Component | Specification | Quantity | Unit Price | Source / Link |
|---|---|---|---|---|
| DS3218 Servo Motor | 20kg high torque | 2 | $10.03 | Link |
| NEMA 17 Stepper Motor | 40mm, replaced by geared version | 1 | $8.21 | Link |
| OpenMV H7 Camera | with FOMO model support | 1 | $80.33 | Link |
| D-100A Power Supply | 5V / 12V dual output | 1 | $23.03 | Link |
| Dupont Cables | Assorted | 12 | $4.08 for 120 unit bundle | Link |
| USB-C to USB-C Cable | Data + power | 1 | N/A | N/A |
| Micro USB to USB-A Cable | Data + power | 1 | N/A | N/A |
Custom V3 PCB Components
| Component | Specification / Package | Quantity | Unit Price | Source / Link |
|---|---|---|---|---|
| XIAO RP2040 | — | 1 | $4.64 | Link |
| A4988 Driver | — | 1 | $2.20 | Link |
| Resistor | 4700Ω, 1260 | 2 | N/A | N/A |
| Resistor | 1000Ω, 1260 | 1 | N/A | N/A |
| Resistor | 10000Ω, 1260 | 1 | N/A | N/A |
| LED | 1260 | 1 | N/A | N/A |
| Capacitor | 10nF, 0603 | 4 | N/A | N/A |
| Electrolytic Capacitor | 10µF | 1 | N/A | N/A |
| Electrolytic Capacitor | 22µF | 1 | N/A | N/A |
| Electrolytic Capacitor | 220µF | 1 | N/A | N/A |
| 3.3V Voltage Regulator | — | 1 | N/A | N/A |
| Push Button | — | 1 | N/A | N/A |
| Pin Header | 2-pin | 6 | N/A | N/A |
| Pin Header | 3-pin | 3 | N/A | N/A |
| Pin Header | 4-pin | 1 | N/A | N/A |
All of the common materials whose prices and links are not included in the BOM where already in my possession or provided by my local instructor.
Total cost is estimated at $196 before taxes and shipping.
7. What parts and systems will be made?
- 3D-printed arm, base, caps, and axial structures
- PCB for microcontroller, motor drivers, and communication
- Software (Python and Arduino IDE) for camera and motor control
- User interface for manual operation and debugging
8. What processes will be used?
- 3D design
- 2D design
- 3D printing (additive manufacturing)
- Laser Cutting (substractive manufacturing)
- Vynil Cutting (substractive manufacturing)
- Electronics production through CNC milling
- Sanding and painting for the finish
9. What questions need to be answered?
The main question remaining is how to synchronize movement across all three axes using data from the camera. Once the final stepper motor arrives and is integrated, I will test and refine the logic for seamless full-range tracking.
10. How will it be evaluated?
- Camera must detect and track a human with consistent results
- Arm must adjust to maintain alignment in height and reach
- Base must rotate smoothly once upgraded motor is installed
- All systems must work reliably as a cohesive, standalone unit
11. What tasks have been completed?
- Full 3D model design and near-complete printing
- Nearly all printed parts have been post-processed
- Custom PCB designed, milled, and soldered
- Camera and two servo axes programmed and integrated
12. What tasks remain?
- Install final NEMA motor and test rotation
- Expand code to include rotation logic
- Polish aesthetic finish of remaining printed parts
- Possibly introduce additional production processes
13. What has worked? What hasn't?
The servo-controlled height and extension system work perfectly. The vision detection system is consistent and responsive. However, the initial NEMA 17 motor proved too weak to rotate the arm, requiring a redesign and an upgrade to a geared motor. I also had to completely rebuild the structure due to mechanical stability issues in early versions.
14. What questions need to be resolved?
The biggest remaining question is motor strength — once the new motor is tested, I'll know if it can handle the weight and torque. If it fails again, a higher-ratio gear system would be required.
15. What will happen when?
- Motor installation and test - within 1-2 days of arrival
- Full-axis code finalization - 2-3 days after motor validation
- Packaging and system tests - Final week before presentation
16. What have you learned?
This project has taught me not only about mechanical design, electronics, and programming, but also about discipline, planning, and iteration. I've learned to manage a complex project across different domains, solve real-world engineering problems, and work through frustration with persistence. Above all, I've learned how to bring a multidisciplinary vision to my projects.