Diode in the DC Positive to prevent Power Injection Feedback

No - this would be bad.

Firstly - Diodes instantly add 0.7V drop across them. At 5A, that's 3.5W it needs to dissipate. So it'd have to be a big one do so safely. Which are not cheap. Cutting the positive is free.
Secondly - if segment 1 was sitting at 12V (after diode) and segment 2 was sitting at 11.7V after the diode, most power for segment 2 will come from segment 1 due to the higher voltage. You'd have to have exactly the same votlage set, which due to resistance of wires, current draw on strings etc just isnt possible to do. You may end up overloading one segment unintentionally.

My simplest thing to say is if you dont want to back feed your controller, and want to do an entire string from PI and not use controller power - there are two options,
1. Pull the fuse on the controller - or -
2. Create a non-power-pass adaptor. This can be as simple as a male and female pigtail (xconnect/ray wu/etc/doesnt matter) - and only connect the data and the ground.
 
misterfied said:
I am just beginning my PIXEL journey and wondering if this technique for preventing power injection feedback in the video above is being used or is it just adding complication? The diodes are really cheap. Thanks in advance
Click to expand...
As others have said bad idea....

Here's how I have my display setup for PI. (There are five psu's in use)

Think of each area as a zone, and that zone is running of one PSU.
When you are about to move from one zone to the next with your data line, run all the lines for the Data, +v, -v into the next zone but just leave the +v line disconnected. Attached is a photo of one of my zone's psu with it's data feed (The black cable with only the -V & Data cores exposed.) The yellow data line then goes to the props in that area and onto the next prop.

Some like to cut the +v line at the prop. That also works, but you then have to repair that cut if you move the prop to another location.
 

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