Dimmer as power starve bit?

Hello, I was unsure of where to ask this, so I posted this here. Apologies if this is out of place!

I have come to love the unpredictable and fascinating timbres which occur with the synth kit when the battery is nearing the end of its juice. Would the dimmer or dimmer slider bit be able to approximate this, or do they both adjust solely the volume/sound level?

I’m aware of people hacking guitar pedals and lo-fi synths to add “power starve” circuits to approximate this sound, but in a way which allows for some reproducibility. I’d love this capability for the synth kit!

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@scuto
Hello Scuto,
I checked the dimmer circuit diagram and saw that the dimmer action is only on the SIG connection…
The power line is constantly +5 Volt so I think a power starve is not possible with this bit…

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@scuto @alexpikkert I don’t know what a power starve sounds like, but you might enjoy trying a light sensor before the oscillator. It’s like a dimmer, but feels more immediate and responsive.

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@scuto
@JackANDJude

A power starve is the effect of a slowly silencing oscillator, giving some unexpected and maybe strange sound effects, caused by the internal circuit becoming unstable before it completely stops.
I think a real effect is only possible by redesigning the oscillator bit.
I tried it by starting the oscillator, connected to the amplifier and speaker, and switching off the power.
But then also the amplifier stops abrupt and there is no starve effect…
Indeed using the light sensor is a very good idea, you could imitate the “theremin” sound with it. Which is the stranges oscillator sound I have ever heard…

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Thank you! I’ll have to look more into the schematics and the like, as I am very much a novice in these realms.

That might sound quite cool, thanks!

I only know what power starve (there might be other names for it, but I’m not familiar with them) sounds like with the littleBits kit, when the 9v battery is running low on power. A power starve circuit theoretically would allow one to control this unpredictability.

@alexpikkert
@JackANDJude
I just noticed the tagging–apologies for not doing so with my other replies.

In the instance where I had unpredictability due to the dying 9v battery, the effect of (what I’m now not totally sure is) the power starve sustained itself for some time–nearly a half hour! I wasn’t recording at the time, so I can’t share a sample for folks to listen and hear if it might be due to another aspect I hadn’t considered, but I will make a recording when I am able.

Yes! The light-sensor theremin would be wicked cool! I wonder… controlling the filter’s cutoff with the light sensor might be the closest approximation, since it’s the closest the LBs have to a sine tone.

I have some low batteries I should test with the synth bits now. :wink:

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Rock 'n roll! Looking forward to hearing your thoughts, regardless if you dig or not. :slight_smile:

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@scuto
@JackANDJude
I tried the power starve idea with an adjustable power supply instead of a 9 Volt battery and started with 9 Volt, slowely going down to zero Volt. Of course the blue power bit will try its utmost to keep the voltage on the oscillator and amplifier bits 5 Volt, but at a certain level it will go down…

See http://youtu.be/3SAlMrxW9no
The oscillator frequency first goes down and then starts making funny noises.
Could turn out nice in a musical instrument… :smile:

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@alexpikkert
Those parts on either “side” of when the power supply is at its lowest are what I’m after. Too cool!
Do you have a particular power supply you would recommend?

@scuto
@JackANDJude
I made my powersupply many years ago and I dont have the diagram anymore.
But there are many kits available on the market, for example from Velleman:
www.velleman.eu/products/view/?id=355452
Take care, dont overstress the power bit by applying more than 9 Volt on it.
Maybe @JackANDJude has a better answer for your question ?

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@scuto, @alexpikkert
I’ve never used a desktop supply, but you could think about designing a power starve bit using the HDK.

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Yeah the light sensor works with the filter very well. At first I used my hands. Then I had an idea of attaching a wire to pulse which controls a bright light bit. The pulse is in sync with the tempo which allows for more predictable sound vs moving your hands. Plus it looks cool.

I recommend getting a few light sensors for the music kit.

Btw thanks for the instructions. I’m using the iconnectMIDI as well and use my iPad as the bridge for the arduino bit.

I’m not sure of the sounds you were getting but I have idea. Kinda like R2D2? I can get some cool but unpredictable sounds by disconnecting the bits while playing. My Monotribe kicks out those sounds in flux mode.

You may want to try a dimmer to a random bit with a threshold bit. You may get what you are looking for.

@scuto Look up the data sheet for the ld1117 voltage reg chip (the one the Powerbit uses I think), I’m pretty sure there’s a fairly simple circuit on it for a variable supply that only uses a couple of electrolytic caps and a couple of resistors(and a 1117v). You’ll want to get an ld1117V (for variable?) in the TO-220 package, and a 2K pot is what I’ve got in my circuit instead of one of the fixed resistors shown. I’ll scan and post my hand drawn schematic if you want, but you’ll wish I hadn’t.
Cheers,
Waxmoose

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@alexpikkert Thanks! I’ll look into that, and I’ll keep an eye out for the 9V threshold.

@JackANDJude I don’t have enough experience yet, but I’ve been considering picking one of the HDKs up once I have a better grasp of electronics. (I have a Rad-Fi kit coming to see if it’ll help me understand things better as far as electronics for music, specifically.) Danke!

@sc4r4b Cool ideas! They might not be what I was looking for w/r/t power starve stuff, but I’ll have to give those a try at some point. Thanks!

@waxmoose Nice, I’ll have to take a gander at that stuff, though I’ll have to get some more electronics knowledge under my belt before taking the plunge. Though I guess trial and error are part of the learning process… :-o Thank you!

Thanks again, everyone–I have some research (and development?!) to do! Now to find the time. Well, make the time!

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@scuto The first circuit I soldered was a 5v regulator, so I know it’s an ok thing for an electronics n00b to try.

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@JackANDJude Thanks for the encouragement! :smile:
I haven’t been able to spend the time yet, but I hope to :soon:

That very nearly sounds like an Atari Punk Console!
With gives me an idea of what to do with the protoboard in the HDK.:+1:

OSM

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