I know that with my Coolpix 990 and a TK-based app, I could take photos under the control of the software. I think this is because the 990 is not a disk over the USB, but instead is controlled by a protocol, based on a Fujitsu chipset, which a number of cameras (not just Nikon) use. I do not know about other coolpix cameras. They are not all the same. For more info, see http://photopc.sourceforge.net/
If the USP connection is lost, the device handle goes away. I would imagine this would upset your software. And, do you mean USB switch or USB hub? I suspect the USB switch is a switch in the sense that a network switch is a switch - there is no actual switch you can control. Not that I have done an exhaustive search for the thing. (I am searching for a Serial->USB converter who's Linux device driver supports ioctls() that wake up when, say, a CD or RTS line change. Oddly, most device drivers seems to have a return(0) there - meaning they don't complain when you try, but they don't do what you want either.) On Mon, 10 Feb 2003 21:26:23 -0500 Joel Hammer <[EMAIL PROTECTED]> wrote: > The question: > > Will a usb switch cut off the connection between the computer and the > peripheral completely, similar to pulling the plug, or do switches have > a "keep alive" capability which will make the peripheral think it is > still attached to the computer? > > That's the question. Here is all the verbiage, if you care to know the > reason why I ask. > > We are going to get a coolpix 4500 for capturing digital images over our > surgical pathology cutting board. > > This camera will be connected to a computer, to automatically upload and > label each image and rename the image appropriately. > > I upload digital images easily with my coolpic 2500 using the usb mass > storage option and a usb cable. The camera mounts as a scsi device. Very > nice. No special software is needed. The 4500 has the same usb mass > storage option, so I assume it will work the same. > > The only hitch is that as soon as you plug the usb cable into the > computer and the camera, the camera more or less switches off all > functions and you cannot take any pictures until you unplug the camera > from the computer. Plugging the cable into just the camera doesn't have > this effect. So, it looks like some message from the usb bus tells the > camera what to do. I tried an experiment. I disabled assigning an irq > to the usb device (PCI) in the BIOS, and removed all modules pertaining > to usb. This had no effect. So, this must be a hardware controlled > behavior, beyond the ability of software to control. I assume that the > usb bus sends some low voltage signal to the peripherals to tell them > they are connected. > > This camera is going to be tethered to a computer with the usb cable > while in use. I don't want the users to have to unplug the usb cable > at the computer to be able to take photos, then plug in the cable to > upload photos, I am thinking that a simple mechanical usb switch box > would solve the problem. Just throw the switch to take photos, throw the > switch back to upload. This will work if the box isn't too smart and > doesn't send some "keep alive" message to the camera when a peripheral > is switched off. I assume a dumb mechanical switch box wouldn't send > any "keep alive" message. However, some switch boxes are smart, and do > send keep alive messages when they are turned off. These are usually the > better sort, and are electronic, not mechanical. > > I could just end the suspense by going out and getting a switch (about > $40 for a nice one), but, I would appreciate hearing others experience > before I spend my employer's money. > > Thanks, Joel > _______________________________________________ > Linux-users mailing list > [EMAIL PROTECTED] > Unsubscribe/Suspend/Etc -> > http://www.linux-sxs.org/mailman/listinfo/linux-users > -- +����������������������������+�������������������������������+ � Roger Oberholtzer � E-mail: [EMAIL PROTECTED] � � OPQ Systems AB � WWW: http://www.opq.se/ � � Erik Dahlbergsgatan 41-43 � Phone: Int + 46 8 314223 � � 115 34 Stockholm � Mobile: Int + 46 733 621657 � � Sweden � Fax: Int + 46 8 302602 � +����������������������������+�������������������������������+ _______________________________________________ Linux-users mailing list [EMAIL PROTECTED] Unsubscribe/Suspend/Etc -> http://www.linux-sxs.org/mailman/listinfo/linux-users
