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digital voltmeter by usb using ATmega8


HI all
I wanna to measure an input voltage from -5V to +5V via ATmega8
how can I use USB connection for that?
the output goes to PC via USB connector
and what is the circuit for this project?


Well-Known Member
Most Helpful Member
the first thing is that to measure +/-5V you need a +/-5V supply, so you will need some chip to make the negative rail. Then you need to feed your measured voltage into opamp to translate it into the 0-5V range that the micro can measure.


Well-Known Member
You don't need a dual supply; a simple resistor divider will work.

You can choose the circuit and base software that suits you best from the demo projects on the page you linked.


thanks for replying, I did it by resistor divider and VUSB :eek:



Active Member
For that solution I would take a FT232 Chip. That's a USB to serial bridge.
PC drivers are availible at the FTDI Homepage ( VCP Driver ).
At Controller side You can use the Integrated USART. That will make the programming and communication easy.

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