Elliot’s Status Report for 11/16

This week I mainly worked towards incorporating the second BLE drumstick to the system controller and fine-tuning our accelerometer thresholds upon integration with the rest of the code. After wiring the second ESP and accelerometer, I used serial output to find the new MAC address, and I dedicated the laptop’s connection functionality across separate threads for each of the boards. Once I was able to reliably connect to both of the sticks, I met with my group to test the new configuration. At that point, Ben had already spent some time deriving the required behavior for our MPU6050 output waveforms, but we hadn’t yet achieved an appropriate method for distinguishing hits on the table from swinging drumsticks in the air. After testing across various surfaces and static thresholds, I noticed that taking the magnitude of our data readings was not sufficient for identifying hit patterns–the sequence of high-magnitude accelerometer output to low-magnitude was too general to characterize a rebound off the playing surface, and instead triggered a high frequency of false readings while idle. I modified the notification handlers in my bluetooth code to attach the sign of the z-axis to our incoming data, thereby allowing us to identify upward and downward swings independently, and using the graph from our prior testing I was able to set up a sequence for detecting valid spikes. By polling for a sufficient negative reading, blocking with a delay, and then taking a subsequent reading, we were able to correctly identify downward hits given the two-point difference. One issue we found, however, was that while the two sticks operated well separately, one of them would suffer from a noticeable output delay when playing simultaneously. An important point to consider was that for any run, whichever ESP made the connection to the laptop second was the one that experienced the performance drop. This problem could be a result of the bluetooth connection or it could be a flaw in our threading architecture; I am hesitant to blame our BLE connection interval simply due to the fact that both microcontrollers are running the same firmware code, but I plan to resolve this issue within the next few days. Overall, I believe my progress and our team’s progress is on track, and this upcoming week I plan to meet with the team to flesh out the system’s HSV/lighting concerns as well as continue to test the CV module extensively.