Team E7: The Wand Makers

Carnegie Mellon ECE Capstone, Spring 2025 — Sharon Lai, Olina Zhang, Nadia Palar

Author: hsuanjul

Team Status Report for 4/26/2025
Posted by : hsuanjul Team Status Reports

Risks and Contingency Plans

  • The custom receiver is to be optimized. The current protocol we use is way too complicated to satisfy our needs. Should be done before the demo, if not we will demo the current working version.

Design Changes & Impact

There is no design changes at this point.

Schedule Updates

No major changes were made and the schedule remains as is.

Unit Tests and Analysis

IR transmission stability:

Sent cloned IR signals to LG TVs and Samsung TVs at different distances (1m, 2m, 3m, 4m, 5m) and angles (0, 15, 30, 45, 60, 75) to the TV. Successful transmission is 100% within 3m and 45 degrees. Successful transmission is 0% out of this range. The current transmission quality is not perfect but would need increase in voltage supply on PCB if we want to further improve it. At the same time, the drawback would not affect the demo, so we are not making changes to the design currently. We would need to address this problem if we want to sell it as a business product in the future.

CNN Model:

Confirmed that the model produces outputs with a success rate of 90% for five gestures and 80% for one gesture, based on performance evaluations from four different users after they learned how to perform each gesture and practice for 5 minutes. Verified that the loss function consistently produces finite values across different mini-batches. Monitored validation accuracy to evaluate model generalization.

No further changes were made to the model architecture, as the current version meets acceptable performance criteria. The CNN model was successfully developed, tested, and validated. The system is functioning as intended.

Progress / Photos

Wand controlling the TV in 1300 coves with cloned signal

Please see the project GitHub.

Sharon’s Status Report for 4/26/2025
Posted by : hsuanjul Sharon's Status Reports

Accomplishments

  • Validation for IR transmission: asked 3 different people to wave the wand at different angles and distances to the TV (cloned version). Note that the appliance being controlled also affects performance. Generally, LG TVs are more responsive than Samsung TVs. The transmission is stable within 3m and within 45 degrees to the normal of the receiver. Transmission is barely successful out of the range.
  • Printed a new wand case: the case was printed successfully but the button was lost, have contacted IDEATE to reprint.
  • Made purchase for final demo: order received by ECE, haven’t picked up

Schedule Update

I remain on schedule

Plans For Next Week

  • Pick up what we bought first thing Monday morning.
  • Make sure we have the button for the new wand case
  • Integrate custom receiver with the mechanical switch with Nadia.
  • Finish up with poster

Team Status Report for 4/19/2025
Posted by : hsuanjul Team Status Reports

Risks and Contingency Plans

  • Firmware Compatibility Issues : The updated firmware is compilable on different machines and we have fixed the previous bugs. However, functional issues may still occur after further testings. So far we have been able to fix the bugs, but if the plan doesn’t work, we would move back to the original firmware and build upon that.

Design Changes & Impact

There is no design changes at this point.

Schedule Updates

No major changes were made and the schedule remains as is.

Progress / Photos

Wand controlling the TV in 1300 coves with cloned signal

Please see the project GitHub.

Sharon’s Status Report for 4/19/2025
Posted by : hsuanjul Sharon's Status Reports

Accomplishments

  • Assisted Olina on CNN model: tested with various waving approaches of the gestures; increased dataset size to improve the inaccuracy problem during runtime
  • Assisted Nadia with the updated HAL firmware: debug, transmitter firmware is compilable, and is being flashed to the firmware

Schedule Update

I wanted to make some minor updates before printing the new wand case. So I am a little bit behind, but will be able to contact IDEATE on Monday.

Plans For Next Week

Print new wand case for final review.

Team Status Report for 4/12/2025
Posted by : hsuanjul Team Status Reports

Risks and Contingency Plans

  • Firmware Compatibility Issues : The updated firmware is compilable on different machines and we were able to successfully flash the firmware to the new PCB. However, functional issues may still occur after further testings. So far we have been able to fix the bugs, but if the plan doesn’t work, we would move back to the original firmware and build upon that.
  • Model Robustness: We reduced the data collection time of the wand to 1.5s (was 8s). This change was meant to make the device more user friendly. However, model performance became much worse than before even the validation accuracy remains high during training. We are working on capturing more data, and worse case we can increase the data collection time.
  • Verification and Validation: We are testing whether the 1.5s data collection window supports accurate gesture classification. Verification focuses on evaluating accuracy, and response time to ensure the model meets MVP requirement. For validation, we are running end-to-end tests to confirm that real user interactions with the wand reliably trigger correct IR outputs.

Design Changes & Impact

There is no design changes at this point.

Schedule Updates

No major changes were made and the schedule remains as is.

Progress / Photos

Wand (Everything put together):

Wand controlling the TV in 1300 coves with cloned signal

Please see the project GitHub.

Sharon’s Status Report for 4/12/2025
Posted by : hsuanjul Sharon's Status Reports

Accomplishments

  • Assisted Olina on CNN model: tested with various waving approaches of the gestures
  • Successfully flashed firmware to new PCB: clone function is now working. Transmitter is able to store IR signal to the external flash and is able to fetch the signal and transmit it. The signal sent out is robust and can be received by appliances. The transmitting distance is closer than we deduced from the data sheet.

Verification

  • Batterylife: turn on the wand without plugging it in. See if the LED for battery is still on after 3 hours.
  • PCB design: the design has gone through design review within team before manufacture. Functioning well so far
  • IR Transmitting and receiving: Tested IR transmission at different distance and angles to the target. The transmission is robust so far with 100% successful transmission within 5 meters and 45 degrees to the target. Failure on transmission largely increase when transmission happens out of this range. I will perform more quantitative test on the transmission later and summarize a more reliable data to compare with our 80% target.

Schedule Update

I remain on track.

Plans For Next Week

Print new wand case for final review.

Team Status Report for 3/29/2025
Posted by : hsuanjul Team Status Reports

Risks and Contingency Plans

  • Firmware Compatibility Issues : The updated firmware is compilable on different machines and we were able to successfully flash the firmware to the new PCB. However, functional issues may still occur after further testings. So far we have been able to fix the bugs, but if the plan doesn’t work, we would move back to the original firmware and build upon that.
  • Product quality : The prototype we currently have may break after a lot of trials. We have been collecting data to train model using our version 1 PCB, and noticeable damage has been caused (one of the buttons is no longer sensitive and the battery port is falling off. We are trying to do most of the testing and trainings on version 1 PCB and development board so that our version 2 PCB remains new.

Design Changes & Impact

There is no design changes at this point. We are working on integrating everything and preparing for the interim design review

Schedule Updates

No major changes were made and the schedule remains as is.

Progress / Photos

Fixed wand button: https://youtu.be/jqVDue59yyQ

New PCB (with close up of through-hole for wire connection to IR LED):

Please see the project GitHub.

Sharon’s Status Report for 3/29/2025
Posted by : hsuanjul Sharon's Status Reports

Accomplishments

  • Assisted Olina on CNN model: tested with various waving approaches of the gestures
  • Successfully flashed firmware to new PCB: resolved version conflicts and weird errors across different laptops.
  • Integrated new model: Confirmed that it is safe to reduce buffer size to 7K (7*1024), given that the model size was reduced by a noticeable amount
  • Adjusted the printed wand model: fixed the button problem of easily being jammed and false long press

Schedule Update

I remain on track. Will be able to showcase at least one type of IR transforming with the wand fully assembled during the interim design review.

Plans For Next Week

Perform minor updates to our design and focus on the interim review. Print new wand case for final review if needed. Update and place the receiver PCB if needed.

Team Status Report for 3/15/2025
Posted by : hsuanjul Team Status Reports

Risks and Contingency Plans

Although there haven’t been a lot of major changes to the updated PCB, we might still encounter bugs when integrating it with the new PCB. At this point the most vulnerable part of the project is the firmware, and Nadia and Sharon are devoting most of the time to it. The old version of firmware is rather stable, so in the worst case where we are not able to completely debug the new firmware, we would make minor modifications on the old firmware.

Design Changes

No changes to our design at this point.

Schedule

We remain on schedule.