Team E7: The Wand Makers

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

Author: npalar

Nadia’s Status Report for 4/12/2025
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Since the last update, we were able to get the clone functionality working and successfully demo cloning and transmitting a LG TV signal during the interim demo. Additionally, I was able to make significant progress in finalizing the functionality for the custom receiver. This involved coming up with a custom IR signal to avoid accidentally aliasing existing signals.

I remain on schedule, though my workload may increase from needing to prepare a more polished and “real-world” demo for the custom receiver for the final presentation. Next steps are continuing to improve the custom receiver functionality and preparing for the final presentation.

Nadia’s Status Report for 3/29/2025
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Since we have our interim demo next week, I spent this week primarily preparing firmware for both the integration test with the wand chassis and CNN as well as further testing the IR transmission between our wand and the custom receiver. More specifically, this involved doing isolated tests with just the CNN and just the IR transmission as we tried to integrate it on the V2 of the PCB. Though it functions on boards, there are still a few kinks to work out that will be easier to do remotely now that we have isolated the issues and each have the necessary hardware and system knowledge to debug and fix.

Next steps are to continue making the IR transmission more robust both in consistency and maximum range; ideally, we want to be able to demonstrate it working at the range listed in the transceiver datasheet (up to 10m) which will require more thorough testing. Though we had some small roadbumps as discussed in the team status report, I remain on schedule to have the firmware ready to go for Monday and Wednesday’s interim demo next week.

Nadia’s Status Report for 3/22/2025
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This week was spent primarily fine-tuning and stress testing the firmware on the arrived boards. Sharon assisted with debugging and ensuring that things were functioning correctly for on the board testing. We also collected some data for testing and validation to be used in the final report and presentation.

Development for the custom receiver is slightly behind schedule. Since I was out of town from Wednesday to Friday, I plan to use this weekend to make up progress to be back on track by next week and the interim demo. Firmware for the transmitter is mostly fine-tuned and ready to be integrated with the model. Our primary goal at this point is to focus on system integration for our upcoming interim demo at the end of the month.

Nadia’s Status Report for 3/15/2025
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The PCB arrived! In light of this, I spent this week making sure that the firmware could flash on to this PCB as well as performing some preliminary hardware tests. I also started laying down the groundwork to add the custom receiver functionality. Since we have multiple copies of the PCB, we are also ordering an additional ST-link debugger so that Sharon and I can both work on verifying the firmware remotely.

I remain on schedule. For next steps, I will continue to test and develop firmware on the board itself to verify it works as expected on the PCB. Additionally, we are looking to order a IR transmitter so we can further develop the custom receiver modules.

Nadia’s Status Report for 3/8/2025
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I spent the bulk of the week leading up to spring break working on the design report due on Friday. I was busier than expected during spring break itself, so not much progress happened during that week. I am continuing to verify and test code on the breakout setup to prepare for flashing onto the board. Currently, the biggest concern on my end is making the code as reliable as possible and ensuring that the user control handling is robust.

I remain on schedule. The PCB is probably going to arrive soon, so I will coordinate with Sharon to come up with a test plan since she will also have to verify the PCB initially once it arrives. Until then, I will work more extensively testing on the breakout/breadboard setup to minimize potential issues during PCB testing and system integration.

Team Status Report for 3/8/2025
Posted by : npalar Team Status Reports

Risks and Contingency Plans

Our biggest concern at this point is ensuring we can successfully integrate before the interim demo. To mitigate this, we will extensively test our individual parts to minimize the amount of sources of error before attempting to integrate onto our custom hardware in the coming weeks.

Design Changes

No changes to our design at this point.

Schedule

We remain on schedule.

Part A (Olina Zhang)

Our product addresses global needs by providing a simple, accessible solution to interact with IR-controlled devices, offering an affordable and user-friendly option without the need for sophisticated or expensive smart home infrastructure. The processes to clone and transmit signals are simple and easy to learn, and the use of clear gestures makes it ideal for non-technologically savvy users. In this way, our wand can bridge the gap for people who may not be familiar with traditional remote controls or more complex voice-activated systems.

Part B (Nadia Palar)

In a cultural sense, our wand is designed to be easily used since it does not inherently rely on languages or symbols specific to any culture. The gestures themselves do not have any specific intonation or meaning since they were chosen chiefly for their optimality with regards to detection instead of any cultural meaning. Further, the wand’s simplicity in design is also intuitive enough for individuals who may not have prior exposure to high-tech gadgets.

Part C (Sharon Lai)

Our wand offers a more environmentally friendly approach than typical remotes because it uses a rechargeable battery. Typical remotes for IR controlled devices use disposable batteries which in turn constitute electronic waste. In a global context where environmental sustainability is becoming increasingly important, our product solution contributes to minimizing the carbon footprint associated with the overproduction and disposal of electronic products, offering a cleaner alternative to traditional methods of controlling devices.

Nadia’s Status Report for 2/22/2025
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This week, I got started setting up some physical tests (loopback, basic communication with the peripherals to ensure working) as well as finishing porting over the preliminary code to FreeRTOS. More generally, using an RTOS will make having concurrency between the user-facing tasks (such as status LEDs, mode switching) easier to implement. I also reduced reliance on a debug terminal with serial since the debugger within the Cube IDE provides many graphical interfaces for using gdb. For deliverables, this also involved documenting the overall flow for the design document due on Friday.

I remain on schedule. Next week, we will focus our attention on finishing the design report since it is due this Friday, and I will begin tests to ensure that we retain full functionality when switching to an RTOS based setup. I aim to have this completed by the end of spring break so we can do more integration tests as well as start evaluating the ordered PCB.

Team Status Report for 2/15/2025
Posted by : npalar Team Status Reports

Risks and Contingency Plans
The most significant risk right now is if our ordered PCB doesn’t work after being ordered because there may not be sufficient slack to redesign and order another PCB after receiving our V1. As such, we are spending substantial time verifying the PCB design before ordering it. Additionally, there are multiple test points on the boards in case hotfixes are required.

Design Changes
No changes to our design at this point.

Schedule
We remain on schedule.

Part A (Olina Zhang):
Our wand-based gesture detection and infrared control technology benefit public health, safety, and welfare in a variety of ways. Our technology eliminates the need for physical switches, which improves safety. It offers a touch-free interaction technique, which reduces the spread of viruses and impurities on frequently handled objects like light switches and TV remotes.This is ideal for persons with restricted mobility, disabilities, or the elderly, who may struggle with traditional remote-controlled devices. The technology allows people to easily control their surroundings with simple gestures, reducing the risk of falls or accidents caused by reaching for physical controls.

In terms of welfare, our product strives to improve people’s quality of life. We want to create a wand that is small, simple to use, and provides consistent results. Our technology provides convenience to a wide spectrum of consumers. This promotes independent living for people with physical disabilities and enhances comfort and usability in smart homes.

Part B (Nadia Palar):
The wand provides a unique and expressive experience for individuals to interact with their technological devices. The wand also gives individuals a way to interact with devices in a more meaningful way as well as express an interest in magic. One such social context in which this might be particularly of note is in the classroom, where the wand could be used to make lessons and engaging with educational material more interactive and appealing for some students.

Part C (Sharon Lai):
One of the primary economic considerations is the final cost of manufacturing the wand. The components involved—IMUs, IR transmitters, and CNN-powered systems—are becoming increasingly affordable due to advances in sensor technology, machine learning, and miniaturization. Our approach allows us to leverage these innovations to create a cost-effective and economically viable option for individuals looking for a new and more expressive way to interact with their technological devices.

Nadia’s Status Report for 2/15/2025
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Initial iterations of the device drivers for the IR receiver and external flash memory have been finished. The codebase is less messy, but there are some restructuring changes that will be finished. Since Sharon has began testing some of the initial firmware, I started a new branch to begin integrating FreeRTOS for task management; this will ideally help with some of the contention and aid with overall robustness and handling. This involves additional restructuring of the code so that various blocks can be more cleanly organized into tasks.

For deliverables, I created more polished versions of our block diagrams for the design presentation this week and started work on the design report document.

I remain on schedule. Next week, I will work with Sharon to complete the first hardware order of the semester so we can get the PCB fabricated as well as begin more thorough development testing for our drivers and overall use-case flow.

Nadia’s Status Report for 2/8/2025
Posted by : npalar Nadia's Status Reports

Since Sharon finished sourcing all of the hardware, we were able to begin setting up the codebase with some simple code using the HAL libraries with the STM32 Cube IDE. This included ensuring the chosen MCU had sufficient peripherals for all of the functionality we wanted to implement as well as allocating these peripherals. As of now, the codebase builds, but is still somewhat messy as we were trying to get a minimum working example up and running.

On the deliverables side, I began work on the slides for the design presentation to reflect the hardware choices we made.

Next steps include making architectural changes for quality-of-life to make integration easier, as well as ensuring that all of the functions will interface correctly with the hardware for easier integration. Additionally, the team will need to finalize our design slides for the presentation the following week.