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Experiments with piezos

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Madgyver

Thu Mar 16 2006, 05:31PM

Registered Member #177 Joined: Wed Feb 15 2006, 02:16PM
Location: Munich, Germany
Posts: 214

Hi, I have some piezo crystals siiting here:

,50,0,0,1,0

If you read to the end of the small article read on:

So, how do you guys think I can mount these buggers? I want to be able to use them in Motors or moving parts, so I can measure stress on them.

Besides, any further ideas what to do with them? Maybe 3 axis accelerometer...?

dan

Thu Mar 16 2006, 06:02PM

Registered Member #223 Joined: Mon Feb 20 2006, 06:42PM
Location: Ottawa, Ontario, Canada
Posts: 125

Damn those are some big crystals. As for mounting them I'm not sure. I guess that would depend on what you wanted to do with them. The PCB soldered to them seemed to work well for pushing force but I don't think it would work well for pulling force. Maybe two clamps on either end secured to the sides of the crystal.

I seen a tremor sensor in one of my project books I bought at radioshack. From memory it used a piezoelectric speaker. One end of a long board was placed on the speaker and the other end had a weight on it. The piezo and board was then sandwiched between two bricks to hold the board on top of the speaker. Apparently this sensor could detect foot steps near by or a train coming from miles away.

Sulaiman

Thu Mar 16 2006, 06:44PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

The crystal resonant frequency of 107 kHz is TC range
in this thread we have Wireless Transmission Of Power

How about a wireless piezo-motor?

As a guide to size, my 6"dia 3 ft high 1800 turn TC is 95 kHz
For the receiver you don't have to use a TC-type coil
for moderate received power a ferrite cored inductor/transformer would be OK
with a big topload.
At such low power maybe a flyback transformer (no diodes) with a small capacitive topload?
I guess just a capacitive aerial direct to the crystal would work too
(other end to EARTH)

I'd definately make a quick seismometer too.

stop4stuff

Fri Mar 17 2006, 07:35AM

Registered Member #64 Joined: Thu Feb 09 2006, 06:25AM
Location: Southampton, UK
Posts: 68

there's a couple of postings on fieldlines.com about using piezos to make electricity from sound see here and here

Dr. Shark

Fri Mar 17 2006, 07:36AM

Registered Member #75 Joined: Thu Feb 09 2006, 09:30AM
Location: Montana, USA
Posts: 711

I have used piezos remotely similar to those for fine-tuning the lengh of a laser cavity. They are good for precicions things like that, but I think they would make rather poor linear motors, as the travel is limited to a few nm. There is a way to use them for rotary motors, this is done in high end camera lenses, see

for example. I don't really know how this works though.

Otherwise, use them to generate insane voltages! Extrapolating from the tiny crystals in piezo lighters, you should be able to get more than 100kV out if you strike them hard(or heat them up quickly?). Build a miniature particle accelerator like the one descibed here

.
Oh, and would you care to sell some of the crystals to me?

Oh, and forget about that sound stuff, for than you want the really thin piezos you find in alarm clocks. They can be used in reverse to act as microphones, in fact you can stick one straight into the mic input of your soundcard and convert, well, sound to electricity.

Madgyver

Fri Mar 17 2006, 06:08PM

Registered Member #177 Joined: Wed Feb 15 2006, 02:16PM
Location: Munich, Germany
Posts: 214

joe doh wrote ...

I have used piezos remotely similar to those for fine-tuning the lengh of a laser cavity. They are good for precicions things like that, but I think they would make rather poor linear motors, as the travel is limited to a few nm. There is a way to use them for rotary motors, this is done in high end camera lenses, see

for example. I don't really know how this works though.

The linear motor I had in mind, works the same as the rotary one. The piezo is used to create a standing wave in a resonator (a stick) which goes up and down. Then the hole thing is swinging one a spring like contraption from left to the right. Both movements (up/down and left/right) are not equal in magnitude.
Now think of this motion as a finger, trying to move a radio tuner button, by tipping on it. Thats how these motors work (sort of)
This also works in linear arangement.

joe doh wrote ...

Otherwise, use them to generate insane voltages! Extrapolating from the tiny crystals in piezo lighters, you should be able to get more than 100kV out if you strike them hard(or heat them up quickly?). Build a miniature particle accelerator like the one descibed here

.
Oh, and would you care to sell some of the crystals to me?

Yeah, I get nasty shocks by just soldering them. Maybe I should try a BB gun on them

joe doh wrote ...

Oh, and forget about that sound stuff, for than you want the really thin piezos you find in alarm clocks. They can be used in reverse to act as microphones, in fact you can stick one straight into the mic input of your soundcard and convert, well, sound to electricity.

might be worth a try anyway, wouldn't hurt would it?

Conundrum

Wed Mar 22 2006, 07:40PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

Hi,

One idea might be to use a Peltier to heat/cool the piezos then store the energy in a capacitor.

-A

Omicron

Thu Mar 23 2006, 02:19AM

Registered Member #131 Joined: Fri Feb 10 2006, 09:25PM
Location:
Posts: 185

Where did you get them? Theyâ€™re huge! As for experiments, I would make a TC using them instead of a cap. Where in the world did you get them!

Carbon_Rod

Thu Mar 23 2006, 02:29AM

Registered Member #65 Joined: Thu Feb 09 2006, 06:43AM
Location:
Posts: 1155

Hmmm, they look like they would fit in a copper tube of a coil gun.
May look neat. lol =]

GimpyJoe

Thu Mar 23 2006, 02:34AM

Registered Member #316 Joined: Mon Mar 13 2006, 01:30PM
Location: Marietta, GA
Posts: 212

you have a bunch, so maybe you could sacrifice a few just seeing how long a spark you can make with one

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