Guys,

I would like to build a circuit with piezo sensor that when vibrated it will turn on a load of 1 amp or so. Can you guys help me out!

Thanks

 

Do not know of a piezo sensor specifically. But a piezo buzzer can be used as a mic and can detect vibrations. So with an amplifier it might be able to give useful signals.

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Bharath Bhushan Lohray.
M.Sc. Electronics.

 

what is threshold value of the amplitude of vibrations on which is based the logic of turning on the load? and what do u mean by a "load of 1 amps"? be more specific please...

 

They do make mechanical switches that respond to movement - automotive security systems use them. That might be a one step approach - not really an "electronic" solution but something to consider.

With the limited information you provided it's difficult to respond however let me make some assumptions and describe with words, a kind of block diagram of how one system might work.

Sensor might be a microphone, as already suggested. Ideally a very wide frequency response might be helpful. That way you can capture more intelligence from the vibration.

Feed the microphone into a preamplifier and small amplifier. Rectify the output of the amplifier so that you have a DC voltage that will vary somewhat according to the output. Use the DC voltage and an comparator (like an LM339) so that it will toggle when a selected threshold is exceeded. Provide the proper relay driver on the output of the comparator to drive whatever load is desired.

At some point you might provide some filtering - that might hopefully focus on the levels of vibrations that represent what you want to see - leaving out the stuff that you don't want. You could also send the signal to your computer for analysis/triggering. That's a bit more complicated but still within reach.

Hope this helps.

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stevez

 

I am experimenting at this time with 2 different piezo elements so I don't think the amplitude is important. I know that the elements on a scope generate voltages ranging from 10mV to 100mV at least.
When this voltage is being generated I want to switch up to 1 amp 12VDC & 1 amp 120VAC..... I have looked for simple circuits to do this but can't find any.

thanks