The Octo manual says during an error condition the status LED and connected LEDs will blink Red during an error condition, so it's pretty clear that you have an error condition. Can you provide more info about this LED power injector that you added? It seems highly likely that this is what is causing the error condition. The first thing I would do is remove the power injector and see if the status LED and attached LEDs stop blinking Red. Maybe this power injector is pushing current back into the Octo RGBpx port. Adding a diode in the 5VDC path to block backflow may be a solution.

Which end of the LED strip is this USB thing attached to? The end opposite of the RGBpx connection?

I would add the diode right where the +5VDC from the Octo attaches to the LED strip. Make sure you put it in the right way. The side with the stripe should be the cathode (negative side) which should attach to the LED stip. The anode should connect to the +5VDC coming from the Octo. This could be tricky to do if its an Aquacomputer LED strip because the RGBpx connector is quite small. If you put it in backwards it won't hurt anything but the LED strip will not get power from the Octo. If installed properly the diode should block DC voltage from flowing back into the Octo. I would do this ASAP as you may damage the Octo. That red LED is flashing for a reason. If it's still flashing when the PC is unplugged, there is definitely voltage feeding back into the Octo RGBpx port.

Instead of the diode, you could try using a heavier gauge cable for the 5-meter extension. The problem you are trying to fix with this power injector is the voltage drop across that 5 meters of wire. Heavier gauge wire will have less voltage drop. You could also run into data transmission problems over that length of cable due to the capacitance of the cable. I had LEDs flicker in a Strimer cable after extending the cable from the controller and that was less than 12 inches (very light gauge wire).

adding a diode may not help. it will have a voltage drop across it of about half a volt for your typical silicon diode. for a 5V power, that's already a massive 10% lost.



Also, the PC and the monitor's 5V don't have the same ground reference so if you only plugged the 5V wire it can have funny results, and the Octo may not like being powered from an output (without the diode that is).
If you connect both the 5V and ground, you then also have two different grounds.. that the data line is referenced to and i imagine that can also make the lighting glitch.


if the 5m cable is causing issues i would honestly consider not using the octo to power the monitor lighting
A Farbwerk Nano is perfect for external use, and you can connect it directly to your monitor's USB, or to a powered USB hub you may be using on your desk already.
If said USB connector has enough juice to go beyond the 500ma a USB port usually provides, you can allow in aquasuite the FW nano to pull up to 2A and get them strings pretty bright.

That's what i use for my desk edge lighting, conected under the desk on a powered hub. works a treat and super bright if i want it (using 6 rgbpx strips, so 90 leds)

Remayz makes a good point about the diode’s voltage drop. A Silicone diode does have a voltage drop of ~0.7V but a Germanium diode’s voltage drop is only ~0.3V which is only 6% of the supplied 5VDC. Either way, getting that diode in place would be a challenge, and the voltage coming from the Octo RGBpx port may already be low due to the 5 meters of wire. He also makes a good point about the ground references being different. What you are doing is generally just not a good idea. Removing the connection from the monitor and trying a heavier gauge cable is probably your best bet other than getting a Farbwerk Nano. The Nano would solve your issue and was designed for just what you are doing (controlling LEDs behind a monitor). You would want the external version #53281. The only difference is the supplied USB cable. The only disadvantage to the Nano is it cost money.

If you are using keyboard shortcut profile switching and Ambientpx, the Nano does need a USB connection to the computer. The external version cable has a standard USB-A connector on one end so you can plug it into a USB port on the back of the computer. It's only 2 meters long though.

I think your solution will work and I guess the USB port on your monitor is smart enough to limit its output current. I don’t know if the Octo or Aquasuite will have a problem with the power coming from elsewhere.

I thought your monitor USB was connected to the PC otherwise yes, it wouldn't make sense.

depends if your monitor acts as a powered hub for the USB ports it has. if it does, the 5M connexion to the PC won't matter.