tl;dr: USB requires a current in the 5V and ground before it will initialize the signal. How can I bypass this safeguard if I want to operate an Arduino with only signal lines between the USB plugs?
I am build an underwater ROV running on an arduino Uno controlling ESCs and thrusters from Blue Robotics.
The system is powered via 50 ft tether to a 12V battery above the water. The onboard ESCs are powered directly from the 12V and have 5V outputs which power the onboard Arduino.
The Arduino controlled via serial USB. I cut a USB A-B cord and spliced 50ft of 20AWG wire between the DATA lines. 5V and GND from the ESC is spliced into the USB-B plug and the arduino powers on just fine.
As mentioned above, without the 5V and GND connected, the USB port will have a fit and throw an error. I have tried shorting the 5V and GND directly, then with a 220 ohm resistor, and then with a 10k ohm resistor. No success. The distance isn't an issue, I have connected a normal 50ft USB cable and the Arduino received signal just fine. I have also tested continuity and my data lines are not crossed.
I know that data-only USB cables exist, but I'm short on time and don't want to add weight of the cable housing to my tether.