NSLU2 Webcam Test

I’m testing another way of joining my three USB cables together. The joint is going to be placed outside so it needs some kind of weather protection. I’m considering using ordinary Ethernet cable instead, but I’m not sure what that would do to the USB signal from the webcam to the NSLU2 computer. Using an Ethernet cable I would have a single, long piece of cable instead of three short USB cables joined together.

Five pieces of heat shrink are used as primary cover for the USB wires. One thin blue piece on each of the four USB wires inside the cable, and one larger white piece on the outside:

And on top of that a piece of duct tape:

The connectors from the second and third cable is wrapped in duct tape too:

Hopefully the duct tape will keep the water out.

A preliminary test setup:

I brought my laptop outside to ease calibration of the webcam. The webcam is connected to the laptop through a USB hub:

After the calibration I brought the USB hub back in and placed it in the windowsill behind the NSLU2 computer:

A quick test of the webcam, now connected to the NSLU2, resulted in an error:

$ webcam
reading config file: /home/thomas/.webcamrc
v4l2: open /dev/video0: No space left on device
v4l2: open /dev/video0: No space left on device
v4l: open /dev/video0: No space left on device
no grabber device available

I did some research and it seems to be related to the fact that the webcam is sharing a USB bus with other devices:
$ lsusb
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 006: ID 05a9:0511 OmniVision Technologies, Inc. OV511 Webcam
Bus 001 Device 005: ID 0409:005a NEC Corp. HighSpeed Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 1307:0165 Transcend Information, Inc. 2GB/4GB Flash Drive

The webcam needs more bandwidth than it can get with other devices on the same bus.

I just need a way to force the webcam on to another USB bus, or maybe lower the bandwidth requirements of the webcam. I didn’t expect installing a webcam to be that difficult, as I’m pretty sure I had it up and running a couple of years ago.

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