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Voltage varier

starsky

Aug 14, 2012
5
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Aug 14, 2012
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Hello everyone,

Just came across this forum and signed up because it looks like it could be a useful information source. Hopefully you can help me out with my opening question...

I am currently experimenting with some miniature vibration motors (the type you find in mobile phones). I would like to be able to vary their speed, which can be done by varying the voltage. Ideally I would like to get hold a device that could produce accurate prespecified voltages upto 3 volts (kind of like an inverse multimeter). Can anyone tell me whether this type of device is readily available and, if so, what it would be called?

Thanks in advance for your help.
 

CocaCola

Apr 7, 2012
3,635
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Apr 7, 2012
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3,635
How do you plan to control the selection, manual switching or what?

I would start with an R-2R ladder as you could tailor it to your needs pretty easy, but there are digital potentiometers and solid state DACs that will do it as well...

You can also just use a rotary switch and click through a ladder of preset values...

There are better ways to do it but they can get complicated for the newbie...
 
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starsky

Aug 14, 2012
5
Joined
Aug 14, 2012
Messages
5
Thanks for your reply.

I literally just want to plug the +ve and -ve cables of the motor in and be able to systematically vary voltage by hand. The reason why I want to do this is because I need the motor to produce different forces of vibration upto human sensory threshold. I need to attach my own eccentric mass and then determine what forces are produced at different motor speeds (voltages). I can work this out mathematically but I'd like to check experimentally.
 

MrEE

Apr 13, 2012
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Apr 13, 2012
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84
You have several options:
- If you have an adjustable power supply - such as a lab power supply-, just use that.
- Use an adjustable voltage regulator such as the LM317. (google it for schematics).
In this case you'll need a fixed supply such as a an old fashion wall transformer with DC output.
- A more advanced version is a PWM control (again google this)
 

john monks

Mar 9, 2012
693
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Mar 9, 2012
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693
You may have to design your own power supply with a 10 turn pot.
 
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starsky

Aug 14, 2012
5
Joined
Aug 14, 2012
Messages
5
Thanks guys. I think a bench power supply from Maplins will do for my preliminary testing.
 
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