Invention, Intellectual Property, and Income

Individual assignment:

1. Develop a plan for dissemination of your final project
2. Complete your final project, tracking your progress:
3. what tasks have been completed, and what tasks remain?
4. what's working? what's not?
5. what questions need to be resolved?
6. what will happen when?
7. what have you learned?

This assignment covers final project dissemination and progress tracking

Dissemination Plan

Purpose To ensure that the design, implementation, testing results, and lessons learned from the E-Bike conversion kit and system architecture are shared broadly to benefit makers, educators, and the DIY community. Dissemination builds visibility, invites collaboration, and helps others learn from my successes and setbacks.

Target Audience

• Makers, Engineers, and Hobbyists
  Individuals who enjoy building electronics or E-vehicles from scratch. They can adapt or iterate on the proofs of concept and contribute improvements.
• E-Bike DIY Enthusiasts
  Riders and builders looking to upgrade or modify their own bicycle with an electric drivetrain. They need detailed schematics, BOMs, and step-by-step instructions.
• Fab Lab & Maker Community Members
  Workshop and hackerspace participants who share resources, conduct workshops, and mentor others. They can integrate the project into local training or group builds.
• Technical Educators and Students
  Instructors in electronics, robotics, or electrical engineering courses. They can adopt this project as a classroom or lab assignment, learning about power electronics, embedded systems, and mechanical integration.

Methods of Dissemination

1. Online Documentation (Project Webpage)
   
   • Create a GitHub Pages site dedicated to the E-Bike project.
   • Include high-resolution images of the PCB layout, schematic screenshots, and mechanical CAD renders.
   • Embed short demonstration videos (e.g., how to assemble the controller, how to wire everything, and live testing footage).
   • Publish complete design files: KiCad schematics, PCB Gerbers, 3D model CAD files (STEP or STL), and mechanical drawings.
   • Provide a fully detailed Bill of Materials (BOM) listing each component, manufacturer part number, quantity, and approximate cost.
   • Host source code repository with well commented firmware (C++ or Arduino), instructions, and a troubleshooting.
2. Social Media
   
   • Share build updates on LinkedIn groups focused on hardware engineering and e-mobility.
   • Post on Facebook maker groups to engage hobbyists and gather feedback.
   • Use concise, visually appealing posts (images of the PCB, short video clips, in progress photos, or screenshots of simulation results).
3. Video Presentation
   
   • Produce a polished 2–3 minute overview video summarizing project goals, system architecture, and a live demo of the e-bike running under controller power.
   • Include voiceover narration explaining each subsystem: power stage, control logic, user interface, and safety features.
4. GitHub Repository
   
   • Create a public GitHub repository for ease access to the documentation.
   • Include a description that explains project purpose, features, and usage instructions.
   • Maintain an “Issues” tab for user questions and community contributions (bug reports, design suggestions, feature requests).

Project Progress Tracker

The following section catalogs all tasks completed to date, tasks still pending, current system status, unresolved questions, and an estimated timeline. This helps keep the project on schedule and provides transparency for collaborators or evaluators.

Completed Tasks

• ✓ Designed the Motor Controller Schematic
  

  • Utilized KiCad to create a complete schematic, including IRFZ44, resistors, IN4007 diode, throttle input conditioning circuitry, brake switch interface, DC‐DC 24->5 V converter, microcontroller (Xiao RP2040), and connectors (battery, 3‐pin for throttle,brake,display, pins for the sensors).

• ✓ PCB Layout Validation & Fabrication
  

  • Converted schematic to PCB layout in KiCad, paid particular attention to high‐current traces (10 mm width), thermal relief for MOSFETs, and distance between high‐power nets to prevent arcing.
  • Routed ground planes, added thermal vias under MOSFET pads, and created silkscreen annotations for component placement.
  • Exported Gerber and drill files, and submitted to PCB fabrication service (1 layer copper).

• ✓ PCB Assembly
  

  • After PCB production, hand‐soldered MOSFETs, DC‐DC converter module, microcontroller, and all (resistors, capacitors).
  • Confirmed solder quality with X‐ray refracted light, tested continuity of power rails and gate‐drive nets.

• ✓ Initial Firmware Development
  

  • Wrote C++ firmware on Arduino IDE targeting XIAO RP2040.   – ADC reading of throttle (0–5 V) with 10‐bit resolution, mapped to 8‐bit PWM duty cycle.
    – Brake switch interrupt (pin change) to override throttle and cut PWM instantly.
    – UART serial logging (9600 baud) for real‐time telemetry: throttle value, current sense reading, temperature reading, battery voltage reading.
  

• ✓ Static Bench Testing
  

  • Connected PCB to a lab power supply (24 V @ 5 A limit), resistive load to simulate motor current draw.
  • Verified that as throttle turns from 0 to 5 V, PWM duty smoothly increases and output voltage follows setpoint.
  • Measured current by reading voltage drop on 0.01 Ω sense resistor through differential amplifier → ADC; confirmed linear scaling.

• ✓ Overload Protection
  

  • Calibrated the op‐amp‐based current sensor: measured known loads, adjusted gain resistors to map 0–30 A to 0–5 V range.
  • Added software limit: if sensed current > 25 A for > 100 ms, cut PWM to 0 and issue fault code over serial. Confirmed with short‐circuit test (~5 Ω load) that fault triggers as expected.

Remaining Tasks

• ⧗ Connect OLED display and battery
  

  • Connect and enclosures the display in the 3D printed screen enclosure.
  • connect battery cells in series and parallel to achieve required voltage (24V).

• ⧗ Fine-Tune PWM Frequency & Duty Cycle Modulation
  

  • Evaluate effect of different PWM frequencies (10 kHz–50 kHz) on motor noise and efficiency. Adjust Timer1 prescaler and TOP value in firmware.
  • Implement a two‐stage current limit: soft limit at 20 A (reduce duty linearly) and hard limit at 30 A (trigger fault).

• ⧗ Real‐World Motor & Battery Testing
  

  • Connect PCB to an actual 250 W hub motor and 24V Li‐ion pack.
  • Record performance metrics: acceleration response, steady‐state speed under various loads, current draw at full throttle, and temperature rise over 10 minutes of constant duty.

• ⧗ Temperature Sensing & Thermal Protection
  

  • Position negative‐temperature‐coefficient (NTC) thermistors on MOSFET heatsink or inside battery pack. Add conditioning circuitry (pull‐up resistor + lowpass RC) to ADC inputs.
  • In firmware, continuously monitor temperature; if > 70 °C, ramp down PWM; if > 80 °C, cut off and flag overheat.

• ⧗ Throttle Response Curve Improvement
  

  • Implement software mapping (e.g., exponential curve) so that initial throttle movements result in gentle acceleration and higher turns yield steeper power. Add a configurable dead zone (0–10% throttle ignored) to avoid jerky starts.

• ⧗ Enclosure Design & Packaging
  

  • Use CAD software (SolidWorks) to model a custom plastic enclosure that houses the PCB, DC‐DC converter, and connectors.
  • Provide ventilation/heat sinks for MOSFETs, rubber gaskets for waterproofing, and mounting flanges to bolt the enclosure to the bike frame. 3D print a prototype for fit validation.

• ⧗ Complete Documentation & Demo Video
  

  • Compile all photos, CAD screenshots, test logs, and firmware code into a coherent project report and step-by-step assembly guide.
  • Capture a 2–3 minute video showing the fully assembled e-bike running outdoors: demonstrate acceleration, braking. Narrate the key technical points and safety features.

• ⧗ Final Presentation Slides & Poster
  

  • Prepare a concise slide deck (10–12 slides) summarizing problem statement, system architecture, design challenges, test results, final performance, and next steps.
  • Design an 24×36″ poster for showcasing at symposiums or maker fairs. Include diagrams, charts (e.g., efficiency vs. load), and key takeaways.

What’s Working

• Throttle -> PWM Mapping: The firmware’s linear mapping of throttle voltage (0–5 V) to PWM duty (0–100%) is stable and reproducible. No visible jitter at low speeds.
• MOSFET Switching: IRFP44 switch cleanly at 20 kHz with minimal switching losses (measured ~2 W per MOSFET at 15 A load).
• Serial Telemetry: Real‐time data (throttle, current, temperature, voltage) prints reliably to terminal at 9600 baud. Useful for debugging and logging.

What’s Not Working

Open Questions

• Regenerative Braking Implementation:
  • Can we feed regenerated energy back into the battery safely without a buck‐boost converter?
  • Do we need a dedicated “reverse” driver stage or can we use the same MOSFET half‐bridge?
  • What charging profile and protection is required for Li-ion cells during regeneration?
• Battery Protection (Fuse vs. Circuit Breaker):
  • Should we add a high‐current auto-resetting polyfuse on the main 24V line?
  • Or is a mechanical circuit breaker with a manual reset preferable?
  • How to balance safety, reliability, and cost?
• BLE Mobile App for Data Logging:
  • Would real-time app readouts of speed, battery state‐of‐charge, and fault codes add significant user value?
  • Does the added complexity of BLE radio (e.g., ESP32) justify the benefits compared to UART-to-USB logging?

Timeline: What Will Happen When?

Date	Task
June 3-4	Print custom enclosure in CAD: include boss features for mounting, heat‐sink locations, cable gland holes, and ventilation slots. 3D print a prototype in ABS for test fitting onto the bicycle frame.
June	Perform full‐load testing on a 250 W hub motor with 24 V 10 Ah battery. Record current draw, speed vs. throttle curve, and temperature rise over 10 minute continuous operation. Document anomalies (e.g., motor cogging, unexpected oscillations).
June	Finalize firmware version 1.1: incorporate temperature‐based PWM derating algorithm, implement soft‐start routine (ramp PWM from 0% to requested duty over 0.5 s), and adjust throttle dead zone. Lock code for release.
June	Film and edit a 2–3 minute demonstration video: intro with system overview, animated block diagram overlaid, live footage of e‐bike accelerating, regenerative braking (if working), and narration describing key features. Compress and upload to YouTube.
June	Complete online documentation: update GitHub repository with final schematics, PCB layout, source code, CAD/STL files for enclosure, BOM, and “how to build” guide. Publish project webpage with embedded video.
June	Finalize slides and poster: prepare PDF slide deck (10–12 slides) for symposium talk and design a 24″×36″ poster with diagrams, photos, test results (e.g., graphs of current vs. time, efficiency curves), and key lessons. Submit all materials to course coordinator.

What Have You Learned?

• PCB Layout for High Current: Allocating wide copper pours (10–12 mm) and multiple vias under MOSFET pads drastically reduces thermal resistance. Combining this with a proper heatsink mounting area is essential to prevent thermal runaway.
• Signal Integrity & Noise Filtering: Long throttle cables introduced EMI noise into ADC readings. Implementing a simple π‐filter (series resistor + two capacitors to ground) or using shielded twisted pair mitigates this problem. Also, digital filtering in firmware (e.g., median filter) helps reject spikes.
• Modular Prototyping: Separating the design into modular test stages (power stage alone, then add current sensing, then add throttle interface) allowed systematic debugging. Each block was validated before integration, saving hours of trial-and-error later on.
• Design for Manufacturability & Serviceability: Silkscreen labels for test points (e.g., “Throttle”, “IRFZ44”, “M-,M+”). For future revisions, consider surface‐mount only to reduce assembly time in small batches.
• Documentation & Communication: Clear, annotated schematics and concise “how it works” sections in the project report significantly reduce confusion for new contributors. Visual aids (block diagrams, flowcharts) aid non‐electrical‐engineers in understanding system logic.

Code and Interface Files

The following files are included as part of the project:

• HTML File – A web-based interface for interacting with the Arduino via serial.
• Arduino Code File – Contains the full sketch used in this implementation.