Prop driving a DMM Display?

CassLan

I'm putting together a multi-tool of sorts and I'd like to read voltages anywhere from -30VDC to 30VDC, and from 0 to 35VAC.
My thinking is if I get a proper DC measurement going I can tell with software on the prop if its AC. And use the props graphical abilities to display this data in various forms (even perhaps like a simple oscope?)

I've looked at several ADC chips and it seems to me they all reference the Voltage used to power them, and that is the highest voltage they can see.

I'm looking to make this a portable device, does anyone have a clue as to how to get this done?
I'm not above hacking up a DMM and using a prop to read the LCD signals but I thought someone might have a better way to approach.

Thanks,

Rick

Paul Baker

What is typically done is to divide the signal down into a scale which can be easily dealt with, say you have a R2R +/-5V ADC, if you divide the input by 6 the +/-30V becomes +/-5V which can be read by the ADC.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

CassLan

Of course...what a very simple way to approach it.

Thanks,

Rick