Opposite Relay

[AtomSoft]

Hey guys, this may sounds like a dumb question but i have a button when the button is pressed it sends out 12v ... what would be the best way to drop that 12v to 3.3v for usage on a uC?

Should i use a few diodes or some type of resistor divider?

Basically whats the best way to take a HIGH voltage in and spit out a smaller one? Its just a signal, not for powering any devices.

 

[be80be]

Resistor divider or a zener diode would give fast turn on times. I've used regulator cheap 32 cents and one piece.

 

[AtomSoft]

Oh wow i even forgot about zener diodes. Thanks

 

[be80be]

I hacked a old laptop that couldn't be fixed do to cost. It had one of them crystal eye web cam's there 3.3 volt. I figured it would be 5 volt glad i did some reading up on them.
They can't take 5 volts from a pc USB. Used some 3.3 regulators on the PC side of things and she works like a dream.

 

[Nigel Goodwin]

Hey guys, this may sounds like a dumb question but i have a button when the button is pressed it sends out 12v ... what would be the best way to drop that 12v to 3.3v for usage on a uC?

Should i use a few diodes or some type of resistor divider?

Basically whats the best way to take a HIGH voltage in and spit out a smaller one? Its just a signal, not for powering any devices.

Just a single resistor will do, the PIC's protection diodes will clip the signal to 3.3V for you, that's why they are there.

However, using two resistors as a potential divider will happily do it as well, there's certainly nothing more complicated needed.

 

[AtomSoft]

Awesome! I wanted to make sure i didnt do too little to drop it. I guess my thoughts were spot on

Thanks everyone.