The weekend of 2/5 and 2/6 was primarily spent revising the proposal presentation based on feedback we had received during the week before that. Afterwards from 2/7 through 2/12, I researched component options and drafted a Bill of Materials (BOM) for our first round of purchases.
(Sorry the image is blurry. I’ve attached the Excel sheet at the end of this post for better clarity)
The five items in this BOM are a piezoresistive force sensor, op-amps (for use with the sensor), a set of cheaper piezoresistive sensors (as a back-up precaution in case the higher quality sensor is damaged), neoprene rubber sheets, and an ESP32 development board. Altogether, these components will form the initial drum pad prototype we’ll need to assess the difficulty of converting forces into electrical signals. If everything goes well with these initial tests, it will even become possible to begin programming the ESP32 to receive these signals and communicate them to a PC, which would allow us to test the software side of this project more easily.
One important detail to note here is the fact that the rubber sheets are made of neoprene. From my research, neoprene is a quality elastic substance which should produce the bounce we’ll need for our drum pads, unlike other synthetic rubbers like polynorbornene. I would’ve liked to order some natural rubber as well to compare the two options, but natural rubber is far more expensive than neoprene and we wouldn’t be able to afford natural rubber for all our drum pads while remaining in our $600 budget.
Regarding ordering/shipping dates, this research unfortunately took longer than expected and so I wasn’t able to submit this order by Thursday (2/10) and as such it will go out this next Tuesday instead (2/15). This is suboptimal scheduling-wise, so to mitigate this loss of time I opted for the quicker shipping options of each product not available through Amazon and I currently plan on developing my testing plans for these components before their arrival so that I’ll be ready to jump directly into testing once they arrive (expected arrival is 2/17). By the next update (2/19) I hope to have these components within my possession and have collected data on the force sensitivity of the sensor.
Here is the BOM in excel form: BOM_18500