I have an external device that needs an analog voltage input. I tried using analogWrite PWM mode on Arduino, but suspected that the external device was picking up the off/on. I researched, and came up with two options -- an RC Filter or a digital pot.
I chose digital pot (AD5206 -- 10K) , partly to keep the external device on a completely separate circuit. I used this tutorial http://www.arduino.cc/en/Tutorial/SPIDigitalPot
I connected the external device negative to A1, external 5V to B1, and the analog input of external device to W1. I wired it up, and it works.
However, I am sure I am doing something wrong. If I put all of the digPot resistance on W1, then I will have a direct short from A1 to B1.
Do I add a resistor between B1 and 5V? How big? If I do this, wont I get skewed results. (If DigPot is at midpoint, wont W1 see 5K of resistance and B1 see 5K plus new resistor -- say 6K total)? Or am I overthinking it.
My objective is to use the DigPot to divide the 5V and put an analog signalling voltage on W1, without creating a direct short. How do I do this?