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vibration/piezo switch help

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lil_vinn

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I'm working on a project that consists of 3 pieces. Ultimately, at rest the heating element needs to be around 290 degrees celcius and then when a vibration is sensed it needs to jump up 60 degrees celcius. Currently with the power supply and heating element are at the higher end so around 350 degrees celcius.

1. power supply: AC to DC converter; on the actual converter it says its a 15v 3.3A, but the sheet that came with it said its voltage outage is 12.6V DC, current output 3A, 30W.

2. vibration switch and circuit: I thought originally I would be able to hook up a vibration switch and at "rest" the power would be directed through a resistor which would make the heating element cooler. And when the vibration was sensed it could then go directly to the heating element making it hotter. However, after doing alot of searching I can't find a vibration switch thats even capable of taking that high of amperage. So I was directed to look into using a SCR. However, I'm not sure how to incorporate the vibration switch into it. Do I need to supply another power source? Or is there a better way to go about this?

3. heating element: nichrome wire

In the end I need a circuit that when at "rest" sends a lower amount of power to the heating element and then when a vibration is sensed more power is sensed, or even simpler at rest the heating element needs to be cooler then when a vibration is sensed.

I hope this is enough information,

I've been searching for this for a very long time and can't seem to find anything that is compatible with what I'm looking for. I don't have a lot of knowledge with electronics but know some.

Thanks
 

chuckey

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The clever way would be to get your vibration detector to increase the power supplies voltage. So the first thing to do is to investigate the power unit and discover if its possible to adjust its output voltage. Once you have done this, all you have to do is to wire the adjustment to your vibration detector.
Looking at it a different way, you have a heater running it 350degs with 12.6 V on it. To get it to run at 290 degs, you must dissipate 290/350 less watts in the heater. But the power is proportional to V^2, so if v is the new voltage then v^2/12.6^2 = 290/350, doing the maths v = 11.46 Volts. So if you put a small resistance in the circuit to drop the voltage to main heater to 11.46 volts then its temperature will fall accordingly. If you then use to vibration detector to short out this resistor then the main heater will go back to its correct temperature. If your vibration detector will not handle very much current, then use a relay, connect the vibration detector to one side of the relay coils, the other side to + or - of the 12 Volts as applicable and use the relay contacts to do the actual current switching. You will need a 12V relay with contacts that can switch greater then 3A.
Frank
 

lil_vinn

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thanks for the advice except i'm sightly confused to what you mean by short out the resistor, how would I go about doing that? So I would have my power supply and then I'd have a resistor to decrease the voltage to achieve the temperature desired. Then the next piece would be a 12v relay and that would be connected to the vibrtation sensor which is then connected to the heating element? But I don't see how that would possibly short out the resistor. Sorry i'm not the most knowledgible on the topic.

Justin
 

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