This week I worked on correcting the aggregation of acceleration measurements, ordering materials for the final prototype, and soldering the heart rate sensors.
In our interim demo, I realized that the magnitude of acceleration was not a good measure of how much the acceleration was changing since we have to account for the force due to gravity. We decided on subtracting pairwise magnitude measurements to determine how much the acceleration changed. I spent time on Monday updating the algorithm. I also spent time thinking about how the final prototype would look. I decided on attaching the belt clipped device to the back of the belt since I felt this would be the least distracting place to the user. This location has the added benefit of not allowing the user to recline or lie down comfortably on their back. I decided on the box to house all the hardware for the belt clip device and submitted a purchase order. I also thought about how the heart rate monitor would be attached to the user. I decided on sweatbands since this would be comfortable and submitted a PO for the sweat bands. I also thought about how the circuitry would be connected and decided to use a terminal block shield that would attach to the Arduino. I will update the schematics from our design review this week to connect to the terminal block instead of directly to the arduino. I also learned how to use solder paste and heat gun to solder the heart rate sensor so far the two HR sensors seem to be working without issue.
This coming week, I will work on updating schematics and building the board that the sensors will plug into.
