Team D0: BARI (Bluetooth Audio Rejiggering Instrument)
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This week Sam delivered the Final Presentation during class. The team looked into the system’s noise, and found the source having to do with the BM83. Unfortunately, there is no time to resolve this issue. The audio path and UI code have been integrated, and DSP effects have been worked on.
The final efforts from the group include finalizing the video, poster, and final report.
Thanks for a great semester on behalf of Team D0!
This week we continued work on the signal path and UI. We started using the new pre-amp on Rev2, observing a large increase in quality. Due to the current chip shortage, our manufacturer was unable to provide us with essential components we needed for a complete Rev2 assembly. As a workaround, we decided to pass the final design’s signal through this pre-amp and then jumping the signal over to one of the Rev1 boards. There is still some noise that appears to be from the ADC, which is being looked into.
The UI is in a usable state, with meaningful variables able to be adjusted, and full control of our input devices (switch, button, encoder).
As a team we also worked on the final presentation, which Sam will deliver next week.
Next week we will wrap up validation, implement our updated MVP DSP effects, integrate the UI and signal path, and work on overall signal path quality. We will also make our video.
Here is our updated schedule:
For a little bit of fun, here is the guts of our beautiful BARI box:
This week Rev2 came in early, which was a nice surprise! Adam has begun assembly on it already. The BARI box has also been 3-D printed. We spent time on the signal path, successfully getting Bluetooth output from the BM83, even from a 1/4″ jack input, using a double buffering I/O scheme for audio streaming. We were unsatisfied with the quality of the old pre-amp, but the new one works a lot better, as verified from some tests in the lab. In addition, work has been done on the UI, with a pixel map and menu structure successfully created.
Next week we will work on the final presentation (probably later in the week) and continue work on Rev2 assembly, UI, and the signal path integration.
This week we worked on hardware interfacing and debugging. Adam and Xingran tested the pre-amp and debugged interfacing with the ADC, and Sam worked on the LCD, receiving assistance from Adam for debugging.
At our interim demo, we expect to show off proof that our ADC is spitting out values and show off that we can interface with the LCD and toggle pixels.
Looking forward we hope to get the full signal path going, which includes interfacing with the BM83. We also hope to complete the BARI Box and the LCD UI. We look forward to ordering Rev2 soon. We are deprioritizing DSP effects, but will include them once the signal path and UI and are completed. In addition, we decided to move from 4 channels to 2 channels for the final product in order to save in complexity.
Here is our updated schedule for the rest of the semester:
This week we finalized assembly of Rev1, worked on interfacing with the BM83 Bluetooth module, and began development on the UI.
We will meet on Monday or Tuesday to discuss our project and adjust our schedule as needed, likely deciding to expend available slack time in the schedule and maybe cut some non-essential parts.
Next week we will finalize what we want to display at the interim demo, and discuss changes we want to make for Rev2, hoping to get that shipped as soon as possible. Work with the BM83 and UI will continue.
No specific media to share in this post, but check out the individual status reports for some progress updates!
Two weeks ago, the entire focus was on writing our design document. This was an extension to our design presentation, and consumed most of our time that week. It’s attached below if you want to check it out!
Our Rev 1 PCB was delivered this past week. Adam and Xingran wrote up a test bring up plan and proceeded to test the boards in Ansys Hall. See Adam’s post for more details, but while some modules worked as expected, there were some set backs. However, this was expected, and was one reason our plan includes Rev 1 as a demo board.
Bring up of low software is now the focus for the group, especially getting the BM83 Bluetooth module to work, and creating a UI. Once we can get an audio signal to a speaker, that will be a huge success, and it’ll be even better if the user has basic control over parameters. As such, Sam is halting work on DSP effects and Xingran will be focusing on work with the BM83.
While we are deviating from our original schedule, the included slack time inhibits any real danger to our progress. The next few weeks will be pivotal to getting a MVP product, but once that is completed, the additional features can be added more easily.
This week Adam gave our design presentation, and we got to see how other groups have refined their project. We met on Friday to update each other on progress, discuss Rev1 budget details, and help debug the SPI protocol that Xingran was implementing.
We faced a risk in that the intended PCB manufacturer charged more than we expected and had an estimated arrival of much later than we deemed acceptable. As a result, Adam found a new manufacture that would be cheaper and offer much quicker delivery. The downside is that we will have to hand-solder some of the components with this service. However, the savings in cost (1/2 the cost) and shipping time (a week or two at most) justify this small setback. Another decision was to buy two Rev1 boards since the overall cost of fabrication would be the same with our supplier. This incurs additional component cost, but we agreed it would be better for risk mitigation to have two boards anyways.
Adam has agreed to take a larger role in the design document next week to give Sam and Xingran more time to work on software development since both are a little behind schedule. However, we are still mostly on track, especially given our ample slack time.
Next week we will work on the design document during class time, Adam will work on the mechanical enclosure, Sam will continue MATLAB prototypes and begin working on STM32 algorithm implementation, and Xingran will continue low level software bring up.
This week we reviewed Adam’s schematic, adding labels/clarifications where necessary and correcting errors. We received feedback from Ryan to include a clipping indicator, which we added to our design specification to be implemented in software. Ryan also suggested a audio-specific ADC, which we decided to use. In addition, we determined that the SPI protocol would be a better choice than the 6800 parallel interface for our LCD display.
We met up to work on the design presentation slide deck, splitting up development of the content on the slides for Adam to present.
Sam and Xingran discussed the implementation of the DSP effects, and due to the limited SRAM of the microcontroller, decided to switch from reverb to delay as an MVP effect. We adjusted the schedule to give Sam another week to work on prototyping the MVP effects in MATLAB
We worked on the overall software block diagram to supplement our hardware block diagram to prepare for the design presentation.
Adam will give a dry run of his design presentation on Sunday to Xingran and Sam to receive feedback for the actual presentation Monday/Wednesday.
We will be ready to order our Rev1 board by Wednesday!
This week we delivered our proposal presentation and finalized the interfaces between systems, specifically between modules and the microcontroller module. This helped Adam with the schematic for the PCB. Also, we selected components and finalized a budget, which is crucial so that we can order our STM32 discovery board and get working on software and firmware development.
We need to review the schematic, both individually for errors, and also with Tom and Ryan to get some expert opinions. It is imperative to get Rev1 finished asap so that we can test it and make changes as needed for the final PCB.
We did not change any requirements, since we fleshed those out before the proposal presentation. However, we made final choices for a lot of components, which helps to firm up our direction.
This has been a huge week for tuning our system specification and documentation. We’re looking forward to the schematic review and to play with the discovery board!
This week we got ready for the proposal presentation, which required firming up our requirements and planning out our team schedule. We spent a significant amount of time on the requirements, breaking them down for each subsystem (pre-amp, Bluetooth, power, UI, microcontroller), and also identifying overall system requirements. This process helped to more clearly define the project and our MVP goals.
We accounted for risk management in our master schedule, and so far do not anticipate any challenges that could jeopardize the success of our project. However, PCB production and shipping time is an unknown, but we assumed the worst-case reasonable time in our schedule, and we still have time for 2 iterations of the PCB. Since last week, we decided on specific effects to focus on (analog overdrive, digital EQ/chorus/reverb), certain aspects of the UI to deliver (USB-C charging), and performed a trade study to analyze component options for each subsystem. The next step is to create a budget and start ordering parts, which we look forward to doing next week!