Antennae and Lunetta!?

Spacebones · Posted: Fri Dec 16, 2011 7:54 pm Post subject: Antennae and Lunetta!?

I'm making a simple lunetta inspired noise machine for my brother for Christmas, but I need some advice on a... feature.

First of all, I suppose I'll explain what I'm doing. I've got a 40106 with LDR's acting as the pots for the oscillators. I've got the outputs of the oscillators (some are pretty high frequency, some are low) feeding into the inputs of a 4093 NAND chip.

I've got it breadboarded now, and the result is amusing. It goes from glitchy white noise to throbby beeping telephone malfunction as the oscillators interact.

I'm packaging it up and sending along a note to give it a Soviet Cold War Espionage device vibe. I'll add a snippet of the 'user's guide' to the end of this post! To further the clandestine comm jamming theme, I'd like to add an antenna to the device.

Would it be possible to add a functional antenna to this thing? And maybe mix in some RF stuff into one of the logic inputs? If this is possible, how might I go about adding it?

And now an excerpt from the K.L.E.P.S.O.C. (Komrade Lenin Eminent Photophobic Satellite Orbit Confounder Device):

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Field tests prove device useful for many thing:
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Foremost interfere communication enemy of USSR
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Antagonize watchful bourgeois canine
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Prodigious interrogate tool
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Low power field microwave: Train antenna on grave woundings operate full power to cauterize. Live for fighting once more (Advise: danger radiate burns on hands and face)
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If agent stricken sight-less, photovoltaic cells communicate lightfulness of agent surroundings. Useful hiding application.
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Convenience battery power. Plus, battery is Soviet invention so great patriotism feeling when used.
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Also AC power possible with correct rectify and transform.
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Blink of lights indicate effectiveness of powerful device. Fast blink, maximum effective!
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Can be used last ditch melee attempt strike foe unconscious.
Lovingly repair device post-strike; device take care of agent—agent reciprocate or else.

Inventor · Posted: Sat Dec 17, 2011 1:31 am Post subject:

recently someone posted about a Lunetta Theremin made from a single NAND gate. It works. Look it up, wire it up, and have a blast!

Les

JingleJoe · Posted: Sat Dec 17, 2011 4:01 am Post subject:

Kabzoer · Joined: Feb 07, 2011 Posts: 82 Location: Belgium

If you mean my weird unstable theremin thing, then go here:
http://electro-music.com/forum/topic-48755.html

Tony void posted a video about it!

other things to try: a 4051 with 8 different oscillators to the input, output to amp,
and not connecting the A, B and C selecting inputs.
Now things get unstable as you bring your hand closer to the floating inputs...

JingleJoe · Posted: Sat Dec 17, 2011 7:06 am Post subject:

Sounds like a motorcycle on an old video game Smile

lovely!

Thinking about it a bit more: if you attach yourself to ground (be careful not to shock yourself) you could act as one plate of the capacitor in the standard cmos schmitt oscillator. There would be unimaginable interfereance, it would probably give different results for every person that tried it and a good chance it wouldn't work; experiment time anyone? Wink

edit: added drawing of what i was thinking

P.S. ran out of characters in image description, just wanted to say, removing that resistor increases the risk of electric shock.

this is probably a terrible idea.png

Description:

the range resistor will probably have to be big, dont use an anti static wrist band because they have a large valuse resistor in series with the connection, instead fashion a wrist band without any additional resistance and enjoy the shockingly good fun!

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MadScientist · Joined: Nov 28, 2011 Posts: 63 Location: Denmark

One thing to keep in mind with these simple noise making oscillators, is that they are likely to be bad for the health of your CMOS chips. Sad

If you have a floating input, the chip is likely to be extremely sensitive to changes in its environment, as we can see in the video. However, it also means that the chip is likely to oscillate at an extremely high frequency, much higher than the audio range. What you hear are just the average, low frequency noises in the high frequency oscillator. Unfortunately, allowing the chip to run in this way, is likely to cause an extremely high power dissipation in the gates used, as the chip is literally switching as fast as it can. The net effect is something close to a dead short across its output, with a power dissipation to match. This may be why the chip changes its tune and sensitivity so quickly. It is dying... Crying or Very sad

Frank.

Inventor · Posted: Sat Dec 17, 2011 10:12 am Post subject:

I say zap the blasted chip in the name of weird science!

The concerns mentioned above are somewhat valid, but they can be addressed easily by using a large (1MEGOHM) resistor in the feedback loop and/or by adding a shunt cap on the input to set a minimum capacitance level (affects dynamic range of frequency).

Another safety concern would be bzzzt-ing the protection diodes on the gate's inputs, which could be addressed by adding much beefier Schottky diodes clamped from the input to the supply rails, said beefiness to handle random static discarge or possibly your insane-in-the-brain energy waves, who knows?

Les

MadScientist · Joined: Nov 28, 2011 Posts: 63 Location: Denmark

Spacebones · Posted: Sun Dec 18, 2011 7:45 pm Post subject:

Thanks for the input guys! I'll try to do some tinkering with the 4093 with a 17" antenna I got from Radioshack and see what I can do. I'd prefer the thing to have some longevity, but I'll just socket the chips in case my tinkering is fruitful, and then my brother can do surgery if necessary.

I'll keep you updated!