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Theremin Circuit? Answered

Does anybody have a theremin circuit that doesn't have coils?

I need it to be compact so programming seems ideal.

A PIC solution might work...any suggestions?

Any other processor is fine also.

No, I can't use a light theremin...

And no, I can't use Harrison Instruments' because its too big and too many connections.

If possible, then this is to be used on fruit flies to see how much activity they do when foreign substances are added. Again, if possible if a PIC solution is used, then can the PIC detect when the flies move because they change an oscillation. Most likely I will wind a coil and place it in the jar and then have it detect. The best way would be to use the PIC to print an output via some sort of display so that the scientific results can be tested.

6 Replies

CrLz (author)2011-11-06

Could you use other devices?

Off hand, maybe something like a webcam motion detection program. Often these control programs are measuring number of pixels that change frame-to-frame. Either using a threshold to essentially output a yes/no or perhaps find a way to get the pixel-change data as output. Make a clear set-up for imaging, perhaps a long, tall and shallow plastic/acrylic terrarium with a high contrast (to the flies) background.

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blinkyblinky (author)CrLz2011-11-06

I am thinking of this too...if it will work, that is...

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CrLz (author)blinkyblinky2011-11-07
"If" is definitely an outstanding question.

However, pixel change=motion detection is very contemporary security cam tech- that seems solved. Work would be implementing the right software.

Imaging the flies is outstanding question. Probably need to experiment. Using careful set-ups could help:
  • Narrow container with high contrast background.
  • Perhaps imaging a sub-section of the enclosure volume, to extrapolate overall activity.
  • UV lighting to fluoresce the flies (?) after a quick spray of highlighter ink (?).
Anyway, good luck...

...and remember Kiteman's law: please post it if you solve it!

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blinkyblinky (author)CrLz2011-11-07

They put the flies on a mini sort of ferris wheel thing within a test tube and spin it. Then they tap it and see how much it aggravates the flies.

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iceng (author)2011-11-05

So you cannot use light,
that leaves thermal, capacitive, hall, sonic and other non contact sensors.
A PIC can do an analog conversion, linearization and offset to suit your ear.

Don't fruit flies release an air born molecular compounds scents from flight.
That would give you integral activity information.


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blinkyblinky (author)iceng2011-11-06

Sonic won't work. Possibly thermal, Capacitive...possibly, hall probably not because that is with magnetic fields. I had in mind something similar to Parallax's linesman imaging sensor...pricy though.

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