Potentiometer giving diff values when EtherTen powered externally

The EtherTen combines an Uno-equivalent Arduino-compatible board and Wiznet-based Ethernet support, along with a microSD card slot and Power-over-Ethernet support. [Product page]
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AndrewTurnerAUS
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Joined: Sat Aug 30, 2014 1:09 pm

Potentiometer giving diff values when EtherTen powered externally

Post by AndrewTurnerAUS » Tue Apr 28, 2015 6:15 am

Hello good people.

First off I'm not a hardware guy, I a software developer. So please be kind in helping me understand my problem. I have a single potentiometer connected to A0, I'm using the example Read Serial. When I power the board from my computer's USB I get solid readings from the potentiometer , no variation in the value printed in theserial window. This is my external power supply.
http://www.jaycar.com.au/Power-Products ... y/p/MP3800

When I connect this power supply and supply voltage past 7.2 volts the output values from the potentiometer start to fluctuate, quite a lot, anything under this is OK. Could anyone shed some light into what's going on here?

angusgr
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Re: Potentiometer giving diff values when EtherTen powered externally

Post by angusgr » Thu Apr 30, 2015 6:19 am

Hi Andrew,

What are each of potentiometer pins connected to? It should be (from one side to the other side) - Ground, A0, 5V. It doesn't matter if it's backwards, as long as GND is on one end and 5V is on the other end - the "wiper" of the pot will move from one end to the other.

If you've checked the wiring and it's correct, can I ask how exactly how much variation are you seeing and what value is the potentiometer itself?

Angus

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