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Rhea’s Status Report for 04/04/2026

What did you personally accomplish this week on the project? Give files or photos that demonstrate your progress. Prove to the reader that you put sufficient effort into the project over the course of the week (12+ hours).

I finished soldering the MCU/mux component with the battery and an on/off switch to take it off the breadboard and make the vibrotactile component fully wearable.

I also worked on writing up an experimental protocol for us to start testing next week and met with Vu to get his feedback on the protocol. 

I met with Iqui to fabricate more cases – we ended up changing the fabrication protocol such that the liquid silicone mixture will get run through the centrifuge twice (instead of once) so that it is fully mixed, since last week we had issues where the silicone wouldn’t cure even after 24 hours. The design of the mold was also adjusted as well to reduce the larger air bubbles. Instead of pressing the positive of the mold into the negative from the top, the positive will get pressed into one half of the mold and the second half is put in place on top of it (like a sandwich). 

Is your progress on schedule or behind? If you are behind, what actions will be taken to catch up to the project schedule?

My progress is on schedule, as we will begin conducting testing with the mocap system all of next week. 

What deliverables do you hope to complete in the next week?

  1. Solder the MCU/IMU component with a battery and on/off switch so that the foot mounted component can be worn without needing to be connected to the laptop. 
  2. Run experiment for testing FPA estimation accuracy 
    1. Label the motion capture data to be processed using Lakshmi’s mocap vs device FPA code 
  3. Make a case for the foot mounted device 
    1. If this does not get done before the experiment on Monday, we will fir
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Team Status Report for 04/04/2026

What are the most significant risks that could jeopardize the success of the project? How are these risks being managed? What contingency plans are ready?

  • AWS lambda functions carry a lot of latency, so even though we are able to send IMU data through bluetooth at a rate of > 180 Hz, the actual processed FPA may be calculated at a much lower rate, causing issues with getting timely vibrotactile feedback. 
    • Mitigation: Instead of using AWS for processing, we isolate the AWS component to just data storage and have a secondary module for the app’s backend that processes the FPA. The FPA processing backend would be composed of the current python scripts we use for calculations that are currently on the laptop. 
  • There could be latency with communicating between two BLE devices (foot mounted wearable + vibrotactile device on the shank), such that the vibration feedback is not able to be sent within our range outlined in our design requirement for intuitive feedback
    • Mitigation: if there is issues with latency, we will just have one MCU on the foot mounted wearable and long cables connecting this MCU to the component worn on the shank so that there is only one BLE device communicating with the laptop and driving the LRAs 

Were any changes made to the existing design of the system (requirements, block diagram, system spec, etc)? Why was this change necessary, what costs does the change incur, and how will these costs be mitigated going forward?

Since the FPA processing for an active session will be done on the smartphone, we are now implementing a backend for the mobile app as well rather than just having all the FPA processing be done using AWS. 

Provide an updated schedule if changes have occurred.

  • No changes to the schedule since the updated Gantt chart we made for the demo. We are going to start testing with the mocap system next week.

How will you analyze the anticipated measured results to verify your contribution to the project meets the engineering design requirements or the use case requirements?

FPA algorithm (Lakshmi):

One of the engineering design requirements was to keep the calculated FPA under a certain degree of error compared to ground truth. To measure ground truth FPA we used mocap markers on the right foot along with our foot based wearable. We then processed the mocap data after collection to determine ground truth FPA, and compared that with the online calculation of FPA from our foot based wearable. I will be running RMSE calculations on the FPA angles, and transforming them to normalize them to the baseline mocap FPA to determine the average degree of error and error per footstep between the ground truth mocap measurement and our foot mounted wearable.

User Comfort (Rhea):

One use case requirement for the device was user comfort, such that the device is unobtrusive and able to be worn while walking for prolonged periods of time. After each experimental session I will provide a user survey where the participant can rank how they felt while walking with the device on. The average score for each users response to the questions will determine whether the device and the soft case I fabricated is comfortable to wear or not. Another use case was to ensure the vibration is interpretable, as we intend to incorporate scaled feedback based on the degree of error. To test this, I will have the participants wear the device and send randomized vibration patterns and intensities and ask whether they can distinguish between the varying intensities. Based on their response to the survey, I will determine whether the percentage of intensity needs to be adjusted or not.

Mobile App (Kaitlyn):

The main use case requirement for the mobile app is that our UI is easily interpretable. In order to ensure the app is an effective and intuitive supplement for patients, we will ask individuals to participate in a short usability survey featuring questions that focuses on identifying certain info in the interface, identifying data points, and correlating recommendations and FPA data. This survey can happen after an experimental session with the physical device, but if necessary can be standalone assuming we give participants the context of our gait retraining device. Based on the survey results, we will adjust the app’s UI/UX accordingly. Particularly, our metric of success is if 92% of survey answers (across 6 trials) are accurate, then we will consider our UI intuitive and user-friendly.

Full Device Testing:

The vibrotactile feedback should be intuitive such that the user can adjust their gait based on the vibrations they feel. After each active session, we will compute the number of steps the user was able to correct after receiving the feedback as a quantifiable metric for the interpretability of the feedback. By taking the percentage of steps that were either accurate or appropriately corrected after feedback out of all steps taken, we can see how well users responded to the feedback.

Our final test for testing the entire device is gait retention, where we will have the user (outfitted with mocap beads) walk on a treadmill with the intent to follow the corrected gait, without the device. By taking the percentage of steps with the correct FPA, we can see how useful this device is for long term rehabilitation.

 

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Lakshmi’s Status Report for 3/28/2026

What did you personally accomplish this week on the project? Give files or photos that demonstrate your progress. Prove to the reader that you put sufficient effort into the project over the course of the week (12+ hours).

  • Met with PhD students Iqui and Vu to discuss methods of shortening the IMU data packet contents so that they could be sent within 20 bytes
  • Finalized stages of mocap testing through discussion with PhD students (needed to test without calibration as well)
  • Fully integrated SageMotion code into the off-device (on laptop) processing of IMU data
  • Tested FPA and rudimentary step detection of SageMotion code by tucking IMU with flashed code under shoelaces, was able to confirm correct step detection
  • Finalized code for LRA vibration demo
  • Finalized code for FPA and step detection demo

Is your progress on schedule or behind? If you are behind, what actions will be taken to catch up to the project schedule?

Progress is on schedule according to updated Gantt chart for demo

What deliverables do you hope to complete in the next week?

  • Test FPA detection accuracy with mocap
  • Understand calibration level difference between mocap and SageMotion
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Kaitlyn’s Status Report for 3/28/2026

What did you personally accomplish this week on the project?

    • Added team members to AWS dashboard via AWS IAM Center
    • Tested AWS Lambda and frontend connection — fully working “Hello World” function
      • wrote out documentation for deploying the backend via AWS CLI
    • Added in Lakshmi’s FPA backend to replace the “Hello World” function (still need to test)

Is your progress on schedule or behind? If you are behind, what actions will be taken to catch up to the project schedule?

We’re slowly getting back on track schedule-wise since Lakshmi’s gotten the FPA backend script working and once I verify the mobile app can properly connect to bluetooth and deploy the FPA script, we will be able to test since the soft case is pretty much ready to use.

What deliverables do you hope to accomplish in the next week?

  • Verify FPA backend is connected and implemented properly
  • (from last week) Integrate AWS Timestream into the mobile app backend
  • Start collecting FPA data (we will be testing with our gaits)
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Team Status Report for 03/28/2026

What are the most significant risks that could jeopardize the success of the project? How are these risks being managed? What contingency plans are ready?

  • Not able to demo the FPA angle live next week, we can only demo the vibration being wirelessly sent to the LRA/HD 
    • Updating the gantt chart accordingly 
    • Cutting down on the amount of tests we are going to conduct with the device due to time constraints
  • Risks with the soft case not curing well in the mold / lots of air bubbles 
    • Making more iterations of the mold until there is one that provides the best results consistently 
  • The parts we ordered were missing for most of this week (we have since found the parts) 
    • Put us behind track on taking the MCU/mux off the breadboard to start user testing
    • We ordered a third round of parts that should be coming early next week so we can finish that in the first half of the week 

Were any changes made to the existing design of the system (requirements, block diagram, system spec, etc)? Why was this change necessary, what costs does the change incur, and how will these costs be mitigated going forward?

No changes were made to the system design. 

Provide an updated schedule if changes have occurred.

  • We are still behind on integrating the FPA code onto our mobile app. We plan on finishing this up this weekend and early next week. 
  • Still behind on testing the device with the mocap system, we plan to start that in the second half of next week 
    • We are also cutting down on the amount of tests we’re going to conduct. We are aiming to only complete the FPA estimation vs. mocap ground truth as well as the gait retention tests (we are getting rid of the tests involving participants outside the 3 of us as well as the marked treadmill test) 
  • We have also decided that for our 3 page UI we want to focus on getting the FPA integration down first (the real-time session page) and then getting to the other two pages (long-term data, recommendations). If we don’t have time to implement them fully, we plan on building UI with no backend integration to show what our planned interfaces would look like.
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Rhea’s Status Report for 03/28/2026

What did you personally accomplish this week on the project? Give files or photos that demonstrate your progress. Prove to the reader that you put sufficient effort into the project over the course of the week (12+ hours).

I met with Iqui multiple times this week to fabricate 5 more soft cases made out of the liquid silicone. I was running into issues where a significant number of air bubbles would get trapped in the mold, resulting in holes in the liquid silicone after it cured. 

I worked on fabricating a new mold for the case based on Dr. Halilaj’s feedback (rounded edges, slightly thicker) and have been working on trying different methods for the case to get rid of the large air bubbles. 

I also discussed with Vu different options for the device adhesive. The wig tape I was intending on using did not stick to the soft silicone material well – it was easily peeled off and removed. As an alternative, I proposed using adhesive/tape used for attaching glucose monitors onto an individual’s arm instead of the wig tape we originally proposed. The glucose tape seemed to work well and stuck to the soft case. 

Is your progress on schedule or behind? If you are behind, what actions will be taken to catch up to the project schedule?

My progress is behind since the soft cases I have been fabricating are not ready yet for the device to be fully wearable. This weekend I am planning on making more soft cases such that the whole device can be taped onto the shank for testing. 

I am also slightly behind with resoldering the MCU/mux component with the battery to take it off the breadboard since the parts we ordered went missing for a few days, however I found the parts so I will work on that early next week. 

What deliverables do you hope to complete in the next week?

  1. Prepare for demo 
  2. Resolder the MCU/multiplexer and attach the battery with the switch so that I can take the MCU off the breadboard 
    1. Print a case for the MCU+mux+battery to make it fully wearable
  3. Make new versions of the soft case and find a way to remove bubbles from the silicone 
    1. Make enough cases for both the left and right LRAs 
  4. Write up experimental protocol for the user testing of the device 
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Lakshmi’s Status Report 3/21/2026

What did you personally accomplish this week on the project? Give files or photos that demonstrate your progress. Prove to the reader that you put sufficient effort into the project over the course of the week (12+ hours).

  • Set up Github repo and reflashed firmware onto wearable IMU to test documentation for future developer/PhD student use
  • Edited code for sending different vibration intensities for in-person device demo with our project advisor Dr. Eni Hallilaj
  • Discussed with Dr. Eni Hallilaj the specifics of moving the FPA analysis processing to the app’s backend (rather than the initial assumption it would be on an onboard computer)
  • Lit review of a new research paper sent to us by Dr. Eni Hallilaj that detailed the differences between scaled feedback and pulsed feedback for programming the vibration commands based on intensity
  • Through resources set up by PhD candidate Vu Phan, I set up mocap FPA analysis for the ground truth mocap testing on personal laptop.

Is your progress on schedule or behind? If you are behind, what actions will be taken to catch up to the project schedule?

On schedule considering earlier adjustments. We are not able to start testing FPA accuracy until we have the wearable’s version 1 that can be strapped to the leg. I’m early on getting the mocap-based FPA algorithm testing in thanks to Vu.

What deliverables do you hope to complete in the next week?

  • Move FPA analysis implementation to the backend of the smartphone app, collaborating with Kaitlyn.
  • Get Apple Developer account set up so that we can make the app portable between different devices for independent testing.
  • Get access to mocap room (courtesy of Dr. Eni Hallilaj’s biomechanics lab) to test data pipeline set up on personal laptop
  • Discuss the calibration techniques for FPA analysis with Iqui and Vu
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Kaitlyn’s Status Report for 3/21/2026

What did you personally accomplish this week on the project?

    • Implemented AWS Lambda and frontend connection (still need to test)
    • Researched AWS Timestream functionality
    • Met with Prof. Halilaj and updated her on mobile app progress, suggested buying (and reimbursing) the Apple Developer Plan so we can test across different devices

Is your progress on schedule or behind? If you are behind, what actions will be taken to catch up to the project schedule?

Lakshmi has finished up the FPA script and once I finish debugging and testing the AWS connection, we should be back on track and ready for the testing stage.

What deliverables do you hope to accomplish in the next week?

  • Work with Lakshmi to fully integrate the FPA script into the mobile app
  • Integrate AWS Timestream into the mobile app backend (to store past session data)
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Team Status Report for 3/21/2026

What are the most significant risks that could jeopardize the success of the project? How are these risks being managed? What contingency plans are ready?

  • We have addressed the previous significant risks with the case, as we now have a hard case, hard flex case, and soft flex resin cases. We are now informed of the different vibration effects through these cases and are moving forward with creating soft flex resin cases.
  • The risks with the FPA processing accuracy are still existing, however we will be addressing these risks during the first two weeks of April as we will move forward with testing then
  • (This is from last week, but we still need to work on FPA integration) We will most likely encounter many bugs with setting up and initializing the AWS connection with our current app (i.e. setting correct permissions, ensuring proper libraries are added, etc.)
    • Contingency plan: We will reach out to TAs during mandatory lab time with strong experience in AWS if we encounter any significant blockers.

Were any changes made to the existing design of the system (requirements, block diagram, system spec, etc)? Why was this change necessary, what costs does the change incur, and how will these costs be mitigated going forward?

No changes were made to the system design. 

Provide an updated schedule if changes have occurred.

  • Since we were focused on fabricating the physical cases, we are still behind on integrating the FPA code onto our mobile app. We plan on finishing this up this weekend and early next week. 

Here’s a link to a folder containing all the photos for the case development.

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Rhea’s Status Report for 03/21/2026

What did you personally accomplish this week on the project? Give files or photos that demonstrate your progress. Prove to the reader that you put sufficient effort into the project over the course of the week (12+ hours).

I met with Iqui multiple times this week for assistance on designing the mold for the case as well as learning the fabrication process. We made 3 different versions of the case using 3 different materials and fabrication methods. 

  1. Hard Case: 3D printed TPU 
    1. This version was the most rigid out of the three, so it absorbed a lot of the vibration when testing different vibration sequences
    2. It is the most sturdiest and most reusable material
  2. Hard flex case: 3D printed soft resin 
    1. Semi hard/semi flexible case 
    2. Also still absorbed a decent amount of the vibrations, making it harder to perceive 
  3. Soft case: liquid silicone that was cured/casted in a separate mold 
    1. The most user friendly/comfortable out of all the cases due to the squishy material
    2. Also the most fragile since it is so soft, which means it could end up tearing/ripping even during one session 

After meeting with Dr. Halilaj with the group, she suggested that we focus the most on the soft case since it is the most wearable out of the three options. 

Is your progress on schedule or behind? If you are behind, what actions will be taken to catch up to the project schedule?

My progress is on schedule since I planned on finishing the case fabrication for the LRA+haptic drivers by the end of this week. 

What deliverables do you hope to complete in the next week?

  1. Resolder the MCU/multiplexer and attach the battery with the switch so that I can take the MCU off the breadboard 
  2. Print a case for the MCU+mux+battery component to make it fully wearable 
  3. Print different versions of the soft case with varying thicknesses 
    1. Make enough cases for both the left and right LRAs