Week 10 Forum - Instrument Presentation

Today in Forum we had to present our instrument. I was happy that my instrument worked and made sound. During my lunch I was having problems with my instrument and I wasn't getting any sound. I worked it out to be one of the switches had gone bust.

Overall I am not that happy with my instrument since there are a lot of features that originally worked but stopped working at the final stages. This is because when I contained all the circuitry in the box it was squashed together and there were problems. The features that originally worked but then stopped were:

PROBLEMS

1) The switch in the middle of the instrument (i.e. the blue LED) is meant to change the timbre when switched ON and OFF. At the moment there is no changed when this switch is activated. This is VERY annoying because I spent quite a bit of time building this into the circuit. The switch is turning a capacity ON or OFF within the signal.




2) Originally all the LEDs switched ON or OFF depending on their ON or OFF state. This is VERY FRUSTRATING since this feature took the longest and added the aesthetic values of a real, commercial device. The blue switch in the middle originally would have a state of ON or OFF and the LED is only meant to light up when the switch is activated (i.e. turned to ON). The yellow LED originally only lit up when the switch was set to ON also.



The LED that does work is the ON/OFF switch on the bottom corner of the device. However this only works when a battery is in use. I have built a 9V power adapter into my instrument which when in use does not activate the ON/OFF LED switch.


3) Getting back to what I was saying earlier: The switch that went bust was the first switch. If you look at some of the pictures further down the page, you can see that I have attached two alligator clips to the terminals. If I hold them in my hands the sound works. The switch is meant to turn OFF the sound from the oscillator. If I hold the alligator clips in my hand and make some sound, I can still turn OFF the sound by switching to OFF. But, this feature is now pointless since if I drop the alligator clips the sound stops anyway.




These three fundamental problems with my instrument have caused a lot of frustration in showing my instrument. This is because these features, which I spent hours on and thought would add that little edge to my creation, now don't work. Not happy!

I just hope I get a good mark because I think I spent about 40 hours on this assignment!

COMPONENTS

In a nutshell my instrument is made up of three parts:

1) A Squarewave Oscillator
2) A Victorian Synth
3) A Piezo Mic

The Squarewave Oscillator is built on the breadboard. Within the circuit is an integrated ON/OFF switch, variable resistor and timbral switch. Whether these features work or not is not the point as they're still there and I spent the time to make them.

The ON/OFF switch works by joining the ground and power wires together on the OFF and separating them on the ON switch. The variable resistor is controlled using a potentiometer and two photo-resistors all in series. The timbral switch, as you already know, is changing the timbre by switching a capacitor ON or OFF.


The Victorian Synth has an ON/OFF switch. This switch does work, it's just the LED that is constantly on (whereas originally it would only light up on the ON position). There is a button that click the speaker. Pressing the button joins the terminals of the speakers and hence makes the sound.

The integrated Piezo was originally going to be inside the box but I was unable to put the Piezo in the circuit in a useful way. Instead I have used it to enhance the Victorian Synth and create other effects such as feedback.


I originally wanted everything to be contained in the box. I didn't think ahead because everything fit inside the box in the early stages. I forgot that once I put the switches and buttons on the top there is going to be less room. This meant that the speaker had to be on the outside. This isn't so bad since it allows me to create sounds by placing the Piezo right over the speaker.

THE DEVELOPING STAGES OF MY INSTRUMENT

My original idea was to have an integrated circuit bent toy. I found this idea too difficult to implement and eventually gave up after breaking four toys.



Originally I was going to have some foil with rice inside on top of the Victorian Synth speaker. I canned this idea when I realized I wouldn't be able to contain the speaker inside the box.












As you can see there are two amplifiers. One is for the instrument output and the other is for the piezo. Ideally I would like to have a small mixer and control the outputs that way.


Don't hold your breath. . .



Sound
Improvising on my instrument [1.6MB]


Video
[22.6MB]



[1] Steven Whittington, Seb Tomzac, David Harris. "Music Technology Forum: Semester 2 - Week 10 - Instrument Presentation". Lecture presented at the Electronic Music Unit, University of Adelaide, South Australia, 11th October 2007.