Physical Computation Final! ThumpCities
So last time I updated, I had displayed the rough schematics for how the newly christened ThumpCities worked. Nothing changed in that department. But with some testing, we came to the conclusion that piezo’s can suck.
Piezo’s make for unruly sensors. Depending upon the application, you may or may not need to temper the voltage output and as a result, the reading. But having the analog values of these sensors results in simply too erratic a value to work with, so taming them is an advantage and proves to be very useful. The circuit we had at the time was a 5.1V Zener diode and a 1MΩ resistor. The Zener diode caps the output at a fixed value no matter what the voltage output of the piezo is. The resistor further tamed the reading.
Unfortunately when we tried this circuit, the readings in Max were still unpredictable and very noisy, setting off masks at unexpected times-activate and deactivate and possibly activate again. Even with thresholds given in Max, we wanted to finesse the the sensory output so we wouldn’t have to worry about overly erratic and possibly debilitating readings.
So to further minimize the unpredictability and smooth out the readings, we added a Schottky diode to make the readings more positive, and added a capacitor with the resistor to create a RC cell that further filters the spiking signal by storing up extra voltage.
Thus, our switch becomes smoother and we have mitigated the piezo aftershock, thus allowing us to fire our masks with each bang.
This is what the final circuit looked like when we had it down.
Here is what the circuit looks like for those of you who actually know how to read electronics. For those who do not, no worries, I can barely do it.
I cleaned the circuit up a bit and trimmed the components.
This is the setup in its entirety!
The visual part of our project actually proved to be equally as difficult. We struggled to decide how our video, appropriately titled Endless Cities by D-fuse, should be revealed: in bits, pixels, lines. Since each drum would control a portion of the screen, we felt it necessary to research the hotspots of the video and determine the design subsequently. Adib handled most of this with the following cogent assessment of our undertaking.
But the true villain in this whole scenario was MAX/Jitter. I do say that something learned from this experience is that having no prior knowledge of a specific program (that is executed in a totally different way than any program I have ever used) is a significant handicap when it comes to keeping a time schedule. We consistently ran into walls throughout the duration of this project. It’s no one’s fault, for not even some experts could really answer our questions. More than anything, they helped us cheat what we actually wanted to do- which was just a fading of a mask after its materialized. How hard is that?
We have not given up on the project, for Adib, Lucas, and I are heavily invested in making this a great performance piece, especially with a more experienced drummer, since that was who it was designed for. I estimate it would take a while before we get back to it, but I think we are all steeped in performance of some kind, so it may sit in the recess of our minds for now.
