Final Project Progress

I've been waiting on a bunch of parts still, so I have yet to tackle the white noise generator, but I'm very close to getting my oscillators working. However, I just can't get pressure on the piezo to translate into any change in volume of the oscillator. I think I need to solder some leads to the piezos or something because they might not be connecting into the breadboard correctly. I also need to start thinking about how I want to enclose my project. The bowls and knobs need to be visible, so I'm just going to have to spend some time figuring out that whole set up.

Here's a picture of my oscillator as is. I was planning on putting a high and low pass filter on each of these oscillators, but the priority right now is getting the piezos to work.

Final Project Report

I'm still waiting on a bunch of pretty crucial parts, so I haven't been able to build a whole lot over the past week. I did, however, draw out the entire schematic. Not sure if I need a volume slider/op amp circuit after all of the filters, but that's definitely a possibility.

https://www.circuitlab.com/circuit/4fxce8/finalproject/

The schematic is just wayyyyy too big to fit here, so here's a link to circuitlab.

Lab Report 8

Experiment

This week, we were tasked with building two transistor based circuits. One acted as a simple switch to turn on an LED, and the other acted as a VU meter, changing the brightness of an LED based on the input voltage.

Here is a picture of the switch circuit we built. It was fairly simple, and the potentiometer controlled the amount of voltage being sent to the LED.

Here is a picture of the VU meter we built. It was definitely more complex, but it actually has some useful applications.

Final Project

I just made a simple square wave oscillator as a component of my final project. I'm going to have two oscillators hooked up to voltage controlled oscillators, with the voltage from the piezo pick ups acting as the control voltage.

I basically used the same schematic as the oscillator we built a few weeks ago.



Basically, the user will use the potentiometer to control the frequency of the drum, and the voltage from the contact microphone will determine the envelope of the sound through a VCA. The oscillator will be running continuously.
Here's a photo of the oscillator.

I'm sure you already know what this sounds like, so I feel like a recording is kind of unnecessary.

Lab Report 7

Experiment

Our experiment today was to build an Operational Amplifier that lets us amplify audio or other AC signals with a positive power supply. We didn't really figure out exactly how this is possible, but I do know that it somehow allows us to also amplify the negative half of the waveform. Here is the completed circuit. The potentiometer dictates the gain of the signal.

In the schematic we were told that for this circuit, V Out = Vin * (-R(f)/Rin). In this case, Rin = 2.2 kOhms, and R(f) ranges from 1 Ohm to 10 kOhm. If we talk about gain in decibels and use the ratio of V Out and Vin, then the maximum gain would be 20log(-2.2kOhms/1Ohm) or 66 decibels, and the minimum gain would be 20log(-2.2kOhms/10kOhms) or -13 decibels. (Something seems off here, the calculator wouldn't let me use a negative value for the R(f)).

Final Project

Here is a diagram of my user interface. It's going to be pretty simple, with just a few pads and knobs.

Here is a flowchart for my controller



Materials List

2 Bowls, preferably wooden ($10)
Drum Pad surface, probably just colored tape. ($5)
Box, with some way to suspend bowls, might need to rig some crazy rubber band deal. ($10?)
4 Piezo Diaphragms ($15)
3 555 Timers (If I use these for noise) ($5)
3 LM58 Op Amps ($10)