Hi everyone We have 8.1 up with a logitech webcam on the end of an astronomical telescope. It works fine with the computer next to the telescope but we want the computer 30 metres away. Is there any way I can do this with usb? Thanks, Steve.
On Tuesday 01 April 2003 18:40, fsanta wrote:
Hi everyone
We have 8.1 up with a logitech webcam on the end of an astronomical telescope. It works fine with the computer next to the telescope but we want the computer 30 metres away. Is there any way I can do this with usb?
I don't know the tength restrictions, but have you tried putting a powered hub at the camera end? Dylan
Thanks, Steve.
-- It is a dark day...
On Tuesday 01 April 2003 19:40, fsanta wrote:
Hi everyone
We have 8.1 up with a logitech webcam on the end of an astronomical telescope. It works fine with the computer next to the telescope but we want the computer 30 metres away. Is there any way I can do this with usb?
Thanks, Steve.
With a single USB cable you are out of luck. The USB design is limited to about 4 to 5 meters per cable. This is due to the signal reflections in the cable, and what needs to be done to manage it (26ns delay to allow the signal to even out before the next is sent... that sort of thing). There are a few things you can do to work around it though... assuming you have a low speed device (which I believe a webcam could be classed as) you can link up a few powered USB hubs in serial... I think it's about 5 hubs plus the initial cable from the PC for the physical limit.. That would give you the 30 meters you want. Another choice would be to look at commercial solutions that provide Ethernet bridges with a USB unit at each end. Not a very cost effective solution though since these things tend to be a bit pricey. C.
On Tuesday 01 April 2003 20:00, Clayton wrote:
On Tuesday 01 April 2003 19:40, fsanta wrote:
Hi everyone
We have 8.1 up with a logitech webcam on the end of an astronomical telescope. It works fine with the computer next to the telescope but we want the computer 30 metres away. Is there any way I can do this with usb?
Thanks, Steve.
There are a few things you can do to work around it though... assuming you have a low speed device (which I believe a webcam could be classed as) you can link up a few powered USB hubs in serial... I think it's about 5 hubs plus the initial cable from the PC for the physical limit.. That would give you the 30 meters you want.
Just dug this reference information up... http://www.usb.org/developers/usbfaq/#cab1 http://www.usb.org/faq/ans5#q3 C.
On Tuesday 01 April 2003 13:00, Clayton wrote:
We have 8.1 up with a logitech webcam on the end of an astronomical telescope. It works fine with the computer next to the telescope but we want the computer 30 metres away. Is there any way I can do this with usb? With a single USB cable you are out of luck. The USB design is limited to about 4 to 5 meters per cable.
Possibly this item from Cyberguys would be of help. Notice it can be daisy chained up to 80 ft. USB ACTIVE EXTENSION CABLE, 16FT The USB Active Extension Cable ensures the signal quality of your USB cable and it ensures that the signal meets the USB's Electrical & Timing Specifications. Using passive cables to entend the length of a USB cable can result in signal errors and is not recommended. The USB Active Extension Cable acts as a transparent USB Hub and buffers both upstream and downstream data traffic. The cable comes in both 8- and 16-foot lengths and can be daisy chained in order to reach up to 80 feet in length. http://www.cyberguys.com/ Item# 131 0950 $ 22.42 each *************************************************** Powered by SuSE Linux 8.0 Professional KDE 3.0.0 KMail 1.4 This is a Microsoft-free computer Bryan S. Tyson bryantyson@earthlink.net ***************************************************
On Tuesday 01 April 2003 12:40, fsanta wrote:
Hi everyone
We have 8.1 up with a logitech webcam on the end of an astronomical telescope. It works fine with the computer next to the telescope but we want the computer 30 metres away. Is there any way I can do this with usb?
Thanks, Steve.
Sure -- USB cables 5 meters long are sold, and seem to work. There are special cables that use th e USB power on the cable to boost signal strength. The manufacturors advertise that several can be chained together. You can also use an AXIS camera, it runs linux inside, and connects to Twisted pair. You can then be up to 4000 km away from your telescope (Anywhere on the internet, but that's the farthest Great Circle distance I can think of.) Paul Alfille
participants (5)
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Bryan Tyson -
Clayton -
Dylan -
fsanta -
Paul Alfille