This past week since coming back from Thanksgiving break, I received all the parts necessary to reflow my sensor data collection PCB. I spent three hours on Tuesday and about an hour on Wednesday reflowing the board as well as soldering on the through hole components. I realized that I had the wrong package for some resistors so I found alternative resistors of the same value and reflowed the board. I also ended up needing to rework the board when I realized all of my diodes were backwards and some parts weren’t making good contact with the metal pads. On Thursday I finished reworking the board and validated that the power conversion circuitry and the rest of the board worked well aside from the ADC I2C communication. I am using an 8 channel 12 bit ADC I2C IC that takes in 8 channels of analog data and outputs them over I2C over the SDA pin. Due to this, I needed to collaborate with Olek to validate the functionality of the chip with the Raspberry Pi that requests data over I2C.
On Friday night I met with Olek for a few hours and the two of us attempted to bring up the I2C communication between the sensors and the Raspberry Pi. We were using the oscilloscope to view the SDA and SCL lines, but did not find it particularly useful or insightful as we were seeing weird behaviors. We met again on Saturday for another couple hours and were able to establish communication over I2C between the PCB and the Raspberry Pi! I think it was because the Raspberry Pi GND and the PCB’s digital ground were not coupled, so the I2C communication wasn’t being established properly. I also validated that the buzzer emits a tone when 3.3V is applied. The last thing I need to do is validate the binary coded decimal rotary switch works correctly, which shouldn’t take long. Currently Olek is working on how to request data from all 8 channels of the ADC and how to generate the PWM signal for the buzzer using the binary coded decimal rotary switch position.
For the upcoming week, I will work on the final presentation slides for Monday as well as work on the final poster due on Thursday. Additionally, I will work to mount the sensors onto the piano keys before Monday in order to take a nice video for the final presentation 🙂 Lastly, I want to validate the rotary switch function and replace some resistors on the PCB such that the indicator LED’s for the key presses are more bright. I believe I am exactly on schedule and can finish my tasks before the final presentation on Monday.