Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
Audio files: 705
Posted: Sun Jan 13, 2013 2:45 pm Post subject:
Fantronic oscillators Subject description: more LED's to listen to
The teacandle oscillators got me thinking what else I have to listen to.
I have a couple of battery powered fan's with LED's that create some nice patterns, similar to this:
[turn the volume down]
so I decided to see what those sounded like.
I replaced the LED's with optocouplers and buffered the signal with some 40106 inverters. The fantronix circuit itself runs
on 4.5 volts but I noticed that by varying the voltage I had a bit of control over the pitch/speed, so I used a variable regulator.
I also added another optocoupler to modulate the voltage. I could have just used a transistor but this was an easy way to
do it and I had a nice space for another optocoupler on the PCB
I also used the spare inverter to create an LFO which can be used to modulate it.
I added a divider which can be used to turn one of the fan LED's into a range of frequencies, and I can select one of those
to modulate the power, so it can selfmodulate But I can also use an external signal.
Then there is the audio section. I used two summing amps and used some different resistors to spread the sound (yes they
make sound) of the 5 LED's over the L/R channels, I also added 2 flipflops (U3) to create a sub sound which can be turned
on/off with a switch or remotely. The switch actually just inverts the remote signal, so if I invert one and attach them both
to the LFO I get a panning effect. there are some other switches and extra inputs but you can probably make out from the
schematic what it all does.
I made a recording when it was still breadboarded, droning together with the Enneatronic Spectralizer, which you can
find here.
PHOBoS - fantronic oscillators schematic.gif
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fantronic oscillators - 01.jpg
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(fantronic oscillators with temporary knobs)
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fantronic oscillators - 03.jpg
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(fantronic oscillators with temporary knobs)
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Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
Audio files: 705
Posted: Sun Jan 13, 2013 7:21 pm Post subject:
Fantronic oscillators demo
ok here's a demo. It's not all too interesting on it's own, but a very usefull addition for my modular lunetta.
And it looks awesome with all the flashing LED's (I might make a similar box for the PWM )
anyway here's roughly what I did:
0:00-0:20 normal play
0:20-0:40 manual pitch control
0:40-1:15 LFO pitch modulation
1:15-1:50 self pitch modulation
1:50-2:00 normal play
2:00-2:20 sub added
2:20-2:40 sub with LFO modulation (panning)
2:40-3:40 all together now
(no efx where added)
I also added a photo of the inside and a close up of the actual 'fantronix' circuit, which I put on a piece of perf
with a resistor and zenerdiode. Mainly to protect it when I was still breadboarding. (just in case)
fantronic oscillators - 06.jpg
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Fantronic Oscillators inside look
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fantronic oscillators - 07.jpg
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Fantronix
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I now find that I'm regularly looking round pound (or 99p) shops looking for things that might be cannibalised. They're very good source of LEDs, especially just after Christmas. I've got even more flickering candles now.
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