Problem with powering Multiple Devices from a USB Hub

I’m having an issue with powering multiple devices from a usb 3.0 un-powered hub. I have connected an Arduino Mega, an Arduino Nano, an action camera (used as webcam) and a Scanse Sweep lidar. When evertyhing tested seperately everything works flawlesly (so no coding problem I assume). When trying to use simultaneously unespected crashes occur randomly.

I assume that it has do to with power issues from the usb 3.0 port on my tx2 because lidar stops rotating and restarts, and when used on the seperate usb port (with the little white adaptor) it doesn’t happen.

What I’d like to ask, first of all, is this possible to happen, or do I have to look for my problem somewhere else? And secondly how I’m I gonna solve this? Is a powered hub the solution? Has anyone tried something similar or has a tested powered hub to propose?

Lastly, it will be helpful if someone can tell me maximum current draw from usb 3.0 port and usb 2.0 port for my Jetson TX2 Dev Kit.


Hi nsarantinoudis, from the amount of devices you have plugged into the hub, it sounds very likely that you need a powered hub. On my robot I also use a powered hub after too many devices caused some sensors to spuriously lose power. USB specifies 500mA for USB2 and 900mA for USB3 (5VDC).

Thanks dusty_nv,

And to me it seems something power related. Do you have a powered hub to propose? What have you used?

Also since you mentioned a robot, it is possible the motors from my robot have an interference with Jetson, since they have the same power source, but Jetson has a dedicated dc/dc converter? I have read strange thing happening from motors causing flactuations to power, but until now nothing has happened to me and I haven’t looked into it.

Hi, did you measure the voltage drop of USB port when all device work simultaneously?

Hi Trumany,

No I haven’t done so. You mean with a multimeter or can this happen from inside linux somehow?
I’ll check with the powered hub since I just got one, and I’ll come back to you when I have something new.

However I noticed another strange thing that makes me believe that is power related problems. My led on the usb camera flickers on its own when on usb power, even if the camera is able to work, but not every time.

Keep in mind that a USB port’s stated standard maximum output current is for that a single port. If you have a HUB and several devices connected, then the sum total of all devices and the HUB combined should never exceed the standard for a single port. Imagine you have a 20A breaker in your home going to a wall plug. If you throw an extension cord on it with 10 sockets, then it won’t matter if the cord is rated at 200A or 20A…the breaker will still pop if any single device or any sum of two or more devices goes beyond that 20A breaker current.

If you use a powered HUB, then not only does the maximum delivery current available go up for a port (standards say so), every single individual port will be able to consume that much without neighbor ports interfering…this would become a per port independent power delivery instead of a cumulative and combined single port value. You really need a powered HUB, or you need to limit the sum total combined current drain to that of a single port or less.

You can measure the ground/5V lines of a USB port with a multimeter. If you draw too much you’ll likely see a significant voltage drop as you add the last device in.

The powered hub was the solution to these problems, I can assure you. With the use of a powered hub, no problem occured again. The robot was tested extensively and nothing strange happened. Thank you all for your help.