 # Arduino UNO ADC with device that outputs -10V to +10V

Hello,

I am using an Arduino Uno along with a datalogger shield. The device that I have to connect it to has two outputs: +10V and -10V and I guess the difference in that is what I need to record.

At first I was told that it was only going to be a single output of 0-10V so I made a simple voltage divider to get a single-ended output of 0 to 5V so that the ADC could read those values safely. But now that I know that that's not the case, I'm a little confused as to how to move forward with this.

Please advise on how I can tackle this situation. I know the arduino doesn't deal with negative voltages. My knowledge is very limited electronically/electrically so I'd appreciate any help I can get!

The Arduino can read negative voltages by connecting the divider to 5volt instead of ground. Leo..

bhoomip92, do you really need both outputs? If the +10 output simply varies between 0 and +10 at the same time the other output varies from 0 to -10, do you really need the - output?

Or is it an isolated output that needs to be tied to the Arduino common? In that case, you may be able to connect the - output to Arduino Ground, and connect the + output to a 4:1 divider.

Have a link to the device?

bhoomip92, do you really need both outputs? If the +10 output simply varies between 0 and +10 at the same time the other output varies from 0 to -10, do you really need the - output?

Or is it an isolated output that needs to be tied to the Arduino common? In that case, you may be able to connect the - output to Arduino Ground, and connect the + output to a 4:1 divider.

I do need both outputs (+ and -). I'm sorry but I'm not sure what "isolated" output means. Is the Arduino common the same as the GND?

Currently I'm looking at http://masteringelectronicsdesign.com/design-a-bipolar-to-unipolar-converter/ to use a summing circuit to work around this.

Wawa: The Arduino can read negative voltages by connecting the divider to 5volt instead of ground. Leo..

Wouldn't the output of the divider still be negative if the incoming voltage is greater than -5V?

Still not sure what the device's specifications are.

If the outputs are isolated (floating), then the -out could be connected to Arduino GND. Then the +out would become 0-20V. So as in polymorph has suggested, could connect the +out to a 4:1 divider. The divider out would then be 0-5V.

If the device has a GND (0V) and the outputs are not isolated, then the -out would have 0V to -10V range and the +out would have 0V to +10V range. Difference being -10V to +10V max.