Minder is a wearable device capable of continuously monitoring a user’s physiology and behaviors while delivering individualized guidance to keep users healthy. Unlike many wearable technologies currently on the market, Minder can be used to track athletic performance by providing accurate heart rate data during strenuous activity, as well posture quality, and context specific data such as the number of steps taken over the course of a day. This health information is transmitted over Bluetooth to a smart phone device where an app allows users to track their stats and receive guidance. This thesis discusses the process through which the Minder system was designed, and how the requirements of the system were addressed.
Three circuit boards were designed over the progression of this project starting with the first development board. Development board 1 allowed us to test two different design approaches and conduct preliminary testing of the parts selected for the system. The first approach used a central microcontroller to implement the core functionality of our system, while the second approach used the microcontroller inside the Bluetooth module to implement the core functionality as well as the Bluetooth stack. After testing, it was decided that the first approach would be best because it reduced the complexity of firmware development that would be required to implement the Minder functionality while not affecting the Bluetooth stack as well as made the system more flexible with the additional pins available on the standalone microcontroller. A second development board was designed to implement this approach while ensuring communication interfaces and GPIO were easily accessible via headers, pads and 0 ohm resistors to make the board easily tested and debugged. The final circuit board is currently being designed as a miniaturized fieldable prototype that will allow for system level testing of our design.
In addition to the circuit board design, firmware for a stand-alone ARM microcontroller and a Bluetooth Low Energy module were developed to implement the system functionality as well as over the air firmware update and serial bootloader capabilities.
Minder has been developed through the hard work of the entire Minder team. My focus has primarily been on the design of the first development board and the firmware development of the Bluetooth module, over the air update and serial bootloader.
The Minder system has been successfully tested on development boards, and is in the process of being miniaturized for further prototyping.
