November 3rd, 2024
Changed power source from external barrel jack converter to built-in USB power source
Reasoning: given the option to use the USB power source connected to the laptop, the microcontroller can be powered a lot more easily and with better consistency.
November 10th, 2024
For communication between the Wireless Receiver and Wired Hub, switch from SPI communication protocol to UART
Reasoning: Our design requires the microcontrollers to transmit information to each other over a distance of at least 5 meters. The SPI communication protocol is designed for short-distance communication, and the signal gets lost after 1 meter. However, the UART communication protocol is capable of receiving/sending information over long distances, including 5 meters
November 21st, 2024
Remove the microphone component from the wearable accessory, and all related wirings.
Reasoning: the microphones available to us were too low in quality to precisely identify and measure the breathing rate of a human. Because we were able to implement 2 out of 3 human signal tests (the heart rate and the skin conductivity tests), we can remove the microphone while keeping the overall functionality of the system.
November 21st, 2024
Remove the wireless receiver microcontroller from the design, and the IR LED on the wearable accessory. The wearable accessory now connects directly to the wired hub through a UART connection.