Thread: USB Voltmeter?
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Old 11-12-2008, 05:37 AM   #5 (permalink)
dcb
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You can also use something like a 4051 to "multiplex" your analog inputs. They can turn one analog pin into 8:
Arduino playground - 4051

They are like $0.47 from mouser. And you have 6 analog pins on the typical arduino. So you will want a couple 4051s.

HCF4051BEY

If your usb can power the voltage monitor, I would say get an iDuino kit for $18. iDuino : Fundamental Logic WebStore, Electronic Kits and Components

so with one *duino and two 4051s (and a bunch of carefully selected resistors) you should be able to build something that can monitor up to 20 voltages
and send a data stream to a laptop, for about $25 all told.

One of the tricks here is that voltage is measured to ground, and you have to select different voltage dividers for each battery connection as you want to limit the voltage to max 5 volts per probe.

I would also suggest using old phone/network cable for the hookup to the batteries.
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