Hello all!

This week, the team has taken the next major step in our hand crank design. They have upgraded from hardware store PVC pipes that were held together with nuts, bolts, hopes and prayers to a 3D printed, adjustable radius crank held together by push pins, hopes and more prayers!

Two iterations of the hand crank were rapidly prototyped. The early-week version used a wooden dowel as a temporary handle to validate geometry and structural integrity. By the end of the week, the second iteration fully incorporated a borrowed crank handle, allowing for more realistic testing and improved ergonomics.

Additionally, the team was very fortunate to observe a DMD patient perform a real benchmark test! This data will be useful later in determining how to tune the tricycle to feel natural to patients.

Special thanks to the patient (you know who you are :D), Dr. Tanja and Ruby.

What’s Next?

The electrical team is still waiting for new gears to arrive to lower the resistance floor of the hand crank. They have received the motor that will power the back of the tricycle and are very excited to get our hands on the VESC controller to start programming it! In the meantime, the electrical team is busy moving away from our perf board circuit to an actual PCB.

On the mechanical side, more iterations are being made to the hand crank. They will be busy designing the mounting mechanisms for the back of the tricycle. Additionally, they will be designing the final hand crank housing so they can move from the current wooden version, to one made of metal!

Anyways, stay tuned and we’ll report back next week!

This week focused on refining our resistance system and tightening integration across electrical and mechanical subsystems.

During our liaison meeting, we demonstrated the current hand crank gearbox and reviewed resistance levels. Our baseline shaft resistance is about 1 Nm, which was deemed too strong for DMD patients. Because of this, we decided to lower the gear ratio from 2.6 to either 2.0 or 1.6. We will order both options and test them to determine which provides the most realistic and comfortable resistance for patients.

Current Hand Crank Housing System Prototype

A major milestone this week was the heart rate monitor demonstration. We confirmed that Bluetooth can transmit heart rate data directly to our microcontroller. This eliminates extra wiring we previously planned to use and simplifies the overall design.

This week we also finalized signal connections between microcontrollers and reviewed the center console display design. The GUI will operate through physical buttons mounted next to the display. We plan to order the battery, display, and input buttons soon.

Overall, this week pushed us closer to a fully integrated prototype. We corrected earlier resistance assumptions, simplified heart rate data transmission, and aligned our subsystem development more closely with realistic patient needs. The next phase will focus on testing gear ratios, validating motor selection, PCB design, and continuing integration across all systems.

This week was focused on feedback, user testing, and continued hands-on progress with our prototype.

Earlier in the week, the team met with our sponsor and liaison to discuss current progress and review expectations moving forward. These conversations helped us better understand where our design is strong and where additional work is needed, especially across subsystems beyond the hand crank. The feedback reinforced the importance of continuing to develop the project in parallel rather than sequentially, which was some of the direct feedback the team received during QRB 1.

Later in the week, the team met with a different DMD patient than last week’s to evaluate comfort and usability related to the hand crank. During this session, the team tested different crank radii and distances to better understand what positions felt comfortable and natural for the user. The patient feedback was valuable and directly informed how the team plans to refine the adjustability of the hand crank moving forward.

Outside of scheduled meetings, the team spent additional time on Friday and over the weekend working in person on the hand crank housing prototype. This allowed us to begin translating design concepts into a physical form and identify practical considerations related to size, mounting, and assembly. Building the prototype helped highlight areas that will need refinement before moving into more advanced iterations.

Overall, this week was very productive for prototyping and big things to come.

This week focused on receiving formal design review feedback from QRB, evaluating as a team how we will move forward with the QRB feedback received, as well as validating hand-crank ergonomics through in-person patient testing.

On Tuesday, the team met in person with our liaison and sponsor to review progress and priorities moving forward. Technical discussion centered on electrical and data collection progress. The electrical team shared that cadence can now be measured directly from the motor. Torque and force estimation methods were reviewed.

Following this meeting, the team completed QRB 1. The QRB committee noted that while the front hand-crank subsystem is well defined, other critical subsystems, particularly the rear electronics housing and braking system, are not yet at the same level of design maturity. The committee identified schedule risk due to the largely sequential development of subsystems. In response, the team has begun adjusting its execution plan to parallelize development the best they can, with upcoming focus on rear motor and battery selection to enable earlier CAD work and system integration.

Hanson (Electrical Team) showing his progress with the hand crank resistance system to the liaison and sponsor in Tuesday meeting.

On Thursday, the team met with a DMD patient to test comfort and usability across different hand-crank radii and handle distances. This session provided direct feedback on reach, range of motion, and perceived effort. Testing helped validate which configurations felt comfortable and sustainable for the user. The insights gained from this session and future sessions will directly inform final decisions on hand-crank geometry and mounting distances.

David, Danilo, Antoine, and Cesar enjoying the sunset as they take the trike back to the IPPD Room after patient testing.

Overall, this week helped us align with our sponsor, coach, and liaison, learn from review feedback, and confirm our design choices through real patient input, giving the team clear direction moving forward.

Hello everyone,

This week RideOn! focused on getting aligned with our coach and liaisons and turning our design ideas into clear, realistic next steps. We held our first coach and liaison meetings of the semester, which helped us confirm priorities and make important decisions before moving further into prototyping.

On the mechanical side, the team selected the gears, shaft, and bearings that will be used inside the hand crank housing, along with the required fasteners to secure them. For the first prototype, the team decided to use wood for the housing so changes can be made quickly and easily. A hexagonal shaft was chosen to simplify torque transfer and gear mounting. Based on liaison feedback, the mechanical team is carefully considering crank radius, handlebar protrusion, and how the rider’s hands will rotate while the tricycle is moving. Large crank radii were discouraged, since resistance matters more than length for achieving a healthy heart rate.

Mechanical team working on the front hank-crank housing

The electrical team spent the week analyzing resistance and torque capability. We reviewed motor constants, gearbox behavior, and expected output at target RPMs, which showed that additional torque and voltage headroom are needed. As a result, we are moving toward a two-motor configuration with added gearing to increase torque without increasing RPM. Heat dissipation was also discussed in detail, especially heat generated by the gearbox, and future enclosure designs will include ventilation to address this.

We also made progress on sensing and data collection. Ruby provided Team RideOn! with a Garmin chest-strap heart rate monitor, cadence sensor, and speed sensors. All of these devices communicate over Bluetooth Low Energy. The electrical team will work on retrieving heart rate, cadence, and speed data directly from these BLE devices to our microcontroller using an ESP32. This allows us to use reliable, clinically relevant sensors while keeping our system flexible and modular.

Several key design decisions were reinforced this week. We confirmed that torque does not need to be measured directly and can instead be approximated using current measurements, which is consistent with existing rehabilitation devices. We also officially moved away from the inverted braking concept due to complexity and implementation challenges, allowing the team to focus on more robust and achievable solutions.

Looking ahead, we scheduled our first patient meeting for next week, which will be critical for validating handlebar dimensions, grip geometry, and overall usability. The team is also preparing QRB 1 slides, finalizing prototype orders, and planning in-person lab work. We’re excited to continue building and testing while keeping the user at the center of every design decision.

RideOn!

Hello everyone,

This week marked an important transition as RideOn! moved into a focused build and refinement stage of the project. After wrapping up last semester’s design milestones, our team met internally to set priorities, align schedules, and identify the key technical challenges we want to tackle early this spring.

On the electrical side, we validated that torque control at the hand crank works, which was a big step forward. At the same time, testing revealed three issues we need to address: excess heat in the system, lower-than-needed torque at our target RPM, and a mechanical failure where a screw backed out of the BLDC motor. To solve the torque limitation, we are moving toward a two-motor approach at the handlebar. The mechanical team is redesigning the handlebar to integrate both motors, while the electrical team is working on how to combine and manage their electrical output safely and effectively. Any enclosure we design will also include proper ventilation to support heat dissipation.

Hand Crank Torque Control Electronics

We also continued refining our sensing strategy. Cadence will be derived from voltage frequency output, and its accuracy proved reliable. For heart rate data, we plan to follow up with Dr. Tanja about using a chest-strap heart rate monitor and figure out how we can communicate with it to recieve heart rate data directly into our microcontroller.

From a systems perspective, we clarified priorities for the semester. The mechanical team is leading handlebar and housing development, the application side is focused on data communication and interface design, and the electrical team is driving sensor integration and motor control improvements. We also made the decision to move away from the inverted hydraulic brake concept due to complexity and implementation challenges, allowing us to focus effort on more robust and achievable solutions.

Beyond technical work, we’re being intentional about team process this semester. We’re setting clearer schedules for meetings and deliverables, planning regular in-person work sessions in the IPPD lab, and making space for team bonding! We also hope to meet with patients as often as possible to keep their feedback at the center of our design decisions.

We’re excited to build on this momentum and start turning concepts into a fully integrated system. Thanks for following along, and RideOn!

Team RideOn! Testing Hand Crank system during first meeting.