Pine-o-clean tremolo

[mjg]

I posted a build report the other week about part of my kid's school science project - a tremolo build.  (http://www.madbeanpedals.com/forum/index.php?topic=25928.0)

Here's the rest of the project - he has built a tremolo using a motor, spring, container, and liquid sloshing around.  There was much science done testing different liquids, and in the end 'Pine-o-clean' was chosen as the tremolo liquid of choice. 

It has two configurations with the container upright wobbling, or horizontal being bounced back and forwards in a pipe.  Amazingly (well, to me anyway) this works out as an almost sine wave tremolo and a square wave, respectively. 

The tremolo has a bit of randomness to it... sometimes the waves come in groups of two or three close together, then with a bit of a gap.  It's a pretty cool sound. 

Example of the waveform coming out of this thing:



He also played around with a solenoid instead of the motor, but that bit isn't finished yet. 

The 'guts':



A 30 second video of it working:

http://graybloomfield.com/guitar/2017/07/30/liquid-tremolo/img_1758/

And a 5 minute video if you want more 'science':

http://graybloomfield.com/guitar/2017/07/30/liquid-tremolo/science2017-480/

[m-Kresol]

this is all sorts of cool. Very creative!

[somnif]

So, basically the liquid sloshing is changing the resistance between two poles and shunting some signal to ground? Or just straight up attenuating the signal?

[PhiloB]

Looks like it was a lot fun.  Great memories


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[mattc]

That's awesome!

[midwayfair]

Awesome. The extra science video was also very good.

[EBK]

I've bookmarked this to look at carefully when I can spend time on it and enjoy.  I'd love to do some modified version of this with my daughter sometime.  She is always asking to help with my projects.

[Luke51411]

That's so cool

[nzCdog]

Surfin wth the Alien!
Very cool project

[mjg]

Surfin wth the Alien!
Very cool project

Well picked.  That's the song he's learning at the moment.

[mjg]

So, basically the liquid sloshing is changing the resistance between two poles and shunting some signal to ground? Or just straight up attenuating the signal?

Yep, the liquid shorts between signal and ground.  What amazed me is that it wasn't necessarily an on/off effect.  It had definite ramping on and off, depending on the angles of the wires and liquid movement. 

I was also surprised that tap water is a pretty crap conductor for these purposes.  Salt water was much better.  Pine-o-clean was the bomb. 

[somnif]

So, basically the liquid sloshing is changing the resistance between two poles and shunting some signal to ground? Or just straight up attenuating the signal?

Yep, the liquid shorts between signal and ground.  What amazed me is that it wasn't necessarily an on/off effect.  It had definite ramping on and off, depending on the angles of the wires and liquid movement. 

I was also surprised that tap water is a pretty crap conductor for these purposes.  Salt water was much better.  Pine-o-clean was the bomb.

Resistance is a function of distance! Grab a glas of water and stick your DMM leads in 1cm apart and check the resistance (Pure water is 18.2M/cm, My "filtered" water is about 1M, my tap water is like 20k and tastes like pool run-off). Then move them closer, then further apart. By sloshing you're changing the liquid distance between the two poles, so variable resistance.

Very cool project.

[mjg]

Lol... Our tap water was about 500k with the leads 1cm apart. 

from memory, whiskey was pretty bad at conducting too.  I got to drink most of the test subjects.  Not the cleaning products though.   

[diablochris6]

Gold medal stuff here. Jack White will probably try and buy this from you at some point.

[somnif]

Lol... Our tap water was about 500k with the leads 1cm apart.

Man your tap water is better than the "6x filtered!" water I buy from the machine at the leasing office, thats just annoying. Yeah my local water has an absurdly high calcium content (desert ground water) and a stupidly high chlorine level because of a bad diatom problem we have in southern AZ. Tap water will go slimey and coat things in a lovely golden brown layer of goop in as little as a couple days, and when they tried lowering the chlorine dose everything started to smell like geosmin and methylisoborneol (ie: muddy and mildewy).

But, hey, at least we get cool things like being able to grow stalactites off our faucets, so that's something I guess.