The SLIDE

Uncle Krunkus · Posted: Thu Sep 15, 2005 9:13 pm Post subject: The SLIDE

Or the Sound Lab Interface Digeridoo Experiment
I decided that the SL is so portable that I wanted to make an instrumental front (and back) end for it. To make it playable "on the street" like an acoustic guitar is.
I came up with this. A 1.5-2M PVC tube (D40mm) with a couple of pieces of framing PVC cut to hold a stripboard slide operated resistive network.
The resistors form a big pot with a connection every 1K (total approx 100K). There's a common which runs the whole way and is connected to every second strip. It can be played with any piece of metal. With a 50-250K pot at either end the whole thing becomes a big voltage divider which I should be able to tune to 1,2 or even 4 octaves along it's length.
I plan on incorporating a small amp and speaker so the tube can be used as a resonator as well. Possibly also a pad to hit with a drum stick hanging off the side. Maybe a simple sequencer which pulses solenoids that open holes down the side to vary the resonant frequency of the tube.
Maybe I've got way to much spare time on my hands?
I hope so!!

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Uncle Krunkus · Posted: Thu Sep 15, 2005 9:17 pm Post subject:

Here's a shot of the resistors and links (each jumps over the other) on the stripboard. The great thing about this way of attaching them is that the whole network can be slid out to be worked on if need be. Sorry about the quality of the pics Embarassed

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jksuperstar · Posted: Thu Sep 15, 2005 11:18 pm Post subject:

Hey that's great! I love the "spiral" circuit board layout of resistors/common especially. It certainly get's my vote for "Best use of a whole bag of 1K resistors I don't know what else to do with".

Resonant tubes is a hobby of mine. If you stuff a bunch of frequencies down a tube, some tend to cancel others out, and null the effect of the holes (if you add them). I guess that's what makes a didje (with no tuning holes) sounds like it does, while a flute (with many tuning holes) is heavily based on more sine waves.

Food for thought before you start drilling.

v-un-v · Posted: Fri Sep 16, 2005 1:47 am Post subject:

Uncle Krunkus · Posted: Fri Sep 16, 2005 2:35 am Post subject:

The playable side of the board is just a series of copper strips. As you short them out you create a moving CV.

v-un-v · Posted: Fri Sep 16, 2005 3:23 am Post subject:

of course- silly me. Too much coffee, not enough sleep!

It's a brilliant idea!

Ooooh I do love this edit button Mosc :)