UNO controlling 12V based device with a Digital Pot AD5293

I have a basic electronics background (555’s, PWM, Monosynth Audio etc) and just started using the arduino (which is amazing fun). I’ve been programming for a long time in asm and c, which makes the coding side pretty easy with the UNO.

I have a device that has a 5.2K POT (3 pin mode) that has 12V passing though it, that I would like to have control over.

I started with MCP4131 tutorial to control a pot passing 5V, it worked great with everything connected to the arduino. I noticed of course that this would not control a 12V device, but I wanted to try things out to make sure I was on the right path.

I have some questions, I found a AD5293 (www.analog.com/ps/psthandler.aspx?pstid=10212&la=en#) which is in the right voltage range (10-15V) with 1024 steps over 20K.(-assumption-) I will get 266 steps between 0 - 5.2K which is acceptable and I hope my assumption on the values is correct.

Now with the previous example with MCP4131, the entire project was running at 5V (UNO and 4131) but with this next step the AD5293 is 12V and the UNO runs at 5V, how is this going to work?

I am looking at the docs for this (www.analog.com/static/imported-files/data_sheets/AD5293.pdf) and I assume that the Arduino will be powering the Logic side at 5V or 3.3V (terminal Vlogic), then terminals A,B,W will be directly connected to where the POT used to be with 12V passing through it. Besides the SPI interface connections to the UNO am I missing something? Does through Ground on the 5293 go to the arduino or to the device I am controlling? Do I need to supply anything else to the chip from the controlled device or the arduino?

Thanks for reading,

  • Wolfgang

PS: I am not sure about how it works between steps with this chip, do they lock the voltage step by step or does it sweep voltage between the current step and the next one?

Have you considered moving the existing pot with a servo? Check the reference pages for example code .