VDM to Arduino to LDD Driver

So I'm starting the project of hooking up my DIY LEDs to be controlled by the Apex. My current plan is the variable speed port (0-10v) to a little voltage divider (now 0-5v) to the analog pins on the arduino which can now read it (0-1023 integer value) then divide that by 4 (0-255ish integer value) then out put a PWM signal to the LDD drivers for dimming.

My concerns are that since the Arduino is being powered by a cell phone charger so they won't share a common ground. I had issues with my current set up in that the LDDs and the Arduino did not share a common ground and so there was significant weirdness. I have the ground of the Arduino just jumped to the ground of the LDD board and this fixed my issues. I'm not as sure how to tie the grounds together being that the apex is a sealed computer type device and not just bare electronics. Would I be able to fix this by running the cell phone charger off of one of my EB8 outlets?

Secondly according to another post that never updated here https://forum.neptunesystems.com/sho...=common+ground, using just this simple voltage divider set up and had problems with reading more than one of the variable speed outputs. Is this a common problem, and if so how might I resolve this issue?

Thanks!

It seems to me that most people who use LDD-driven DIY LEDs just use this: http://www.stevesleds.com/Aquarium-C...ess_p_183.html

Ok so looking at the installation instructions for the board listed, the 0-10v outputs each have two wires connecting the to the board. I'm guessing that either the (-) lead for each of the connections to the variable speed ports is attached to the ground of the board, or that its comparing the voltages at two pins, one connected to the (+) variable speed port lead and the other to the (-) variable speed port.

Is it safe to allow the (-) leads of the variable speed ports to connect to the ground of the arduino and LED PSU? Or rather where can I tap the ground of the Apex safely to tie everything together? This seems like the only way to allow the arduino to read the voltage signals.

The negatives from the varspd would need to be commoned to board ground and the positives to the voltage input headers.

You might be an engineer if...You have no life and can prove it mathematically.

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Originally Posted by zombie

The negatives from the varspd would need to be commoned to board ground and the positives to the voltage input headers.

You might be an engineer if...You have no life and can prove it mathematically.

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This is what I was thinking, but I was concerned about it sinking more current than would be acceptable. It seems its fine to do this then? I was thinking about maybe putting a current limiting resistor or a fuse on that ground connection just to play it safe since the apex is like $800...

did you figure it out..please share your wiring diagram