need a simple schematic made

[lil_vinn]

I need a schematic made for a homemade project. Currently I have a 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.) And a heating element that when connected is at 350 degrees C. I need a circuit/schematic that uses a vibration sensor and when a vibration is sensed the heating element needs to be at 350 degrees celcius but when a vibration is not sensed it needs to be at 290 degrees.

I have a heating element running at 350degs C with 12.6 V on it. To get it to run at 290 degs, I must dissipate 290/350 less watts in the heating element. 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 I need to put a small resistance in the circuit to drop the voltage to main heating element to 11.46 volts then its temperature will fall accordingly. I need to use to vibration detector to short out this resistor then the main heating element will go back to its correct temperature. My vibration detector will not handle very much current, so I need to use a relay and 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. So I will need a 12V relay with contacts that can switch greater then 3A.

I hope this is enough information its fairly simple however I don't know how to make a schematic to meet what I want.

Thanks,
Justin

 

[mister_rf]

For a project like this you need to specify what type of vibrations you want to monitor. Basically a piezoelectric sensor will do the job. The signal produced by the sensor must be amplified, rectified and will be turned on via a relay to the coil.
A list of similar projects (some need minor adjustments):
Shock alarm circuit - Electronic Circuits and Diagram-Electronics Projects and Design
Vibration Sensor/Detector circuit
**broken link removed**
Seismic / Vibration Sensor vibration seismic sensor diagram

 

[lil_vinn]

How can I determine what type of vibrations I want to moniter? In essense I have a vase full of water set on top of the sensor. When bubbles are created in the vase it makes a small vibration and thats when it needs to adjust the temperature. And I know this sounds dumb but I just don't understand what the schematics are saying, so I'm not sure how to adjust them to do what I want.

 

[mister_rf]

:grin: In this case maybe that’s more simple just to measure the temperature and to adjust the voltage accordingly (switch to a lower range, insert resistor, etc.) in order to lower down the temperature.

 

[lil_vinn]

Well since its for a project at school and the only other thing I need to do is get this circuit to finish the project I can't do that so that won't work.