|This month, Paul Grosse gives you more insight into
some of the topics dealt with in HelpDesk and HelpDesk
Using a low-cost laptop webcam for close-up work
If you have ever needed to look inside something or see something close-up, the ideal answer is of course, the endoscope. However, using a highly specialised piece of medical equipment that can be sterilised to look inside your printer or take photos for your son's school project on arthropods; or the many, small, flowering, non-grass plant species that occupy the place in the garden where the lawn used to be before you became interested in computers, you perhaps need to look at some of the solutions that cost less than a mainframe to buy.
The camera on the right was bought for only £20 and
is around 17mm across (diagonally) so it will fit into
some fairly small holes. It also comes on a thin
goose-neck that is around 30cm long and on the other end
is a USB plug -- the intention being to plug it into the
USB port on the back of your laptop, bend it into
position and use it as a webcam. It will focus from
around 30cm to infinity and gives a reasonable picture.
In order to make it see things that are a
little closer, I have taken the frame counter lens from a
disposable camera and (it just happened to be the right
size and about the right power) secured it in the lens
recess with some Blutak. With this in place, it will
focus on things that are around 15mm from the lens with
the sort of depth of field that you would expect from
such a short lens. Note that you can see the hairs on the
spider's legs but the plane of the object that is in
focus is fairly thin and legs in front and behind are out
Again, it is less than a centimetre across and, like
all close-ups, the depth of field is fairly small.
If only we could get a camera that small.
You might wonder why there are no pictures of mammals -- this is because, although I was capturing the frames using a piece of video editing software so that I could pick a good frame that was in focus and had reasonable composition (also, this webcam doesn't take stills), Bubbles the Hamster and Aphy the mouse wouldn't stay still long enough (clearly the snail did). I've never seen a hamster eat cheese before. Never work with children and animals.
Linux -- Setting up a printer server on a network
Setting it up on a Windows machine is fairly straightforward so we will concentrate on Linux where there is less support for this.
Once you have followed the instructions on the printer server, you will need to let the machines on your network know that it is there. One way of doing this is to put its address and name in a file with the list of hosts.
On each machine, whether it is Windows or Linux, there should be a file called "hosts" (no extension). On Linux, it is located in the /etc directory and on Windows, it is usually in C:\Windows. This file lets the computer know the name, any aliases and the IP address of any computer on the network and the file has a simple structure:
Each line has: the IP address; Fully qualified host name; Short host name; and then, any remarks.
Remarks begin with a # and each field in each line is separated by spaces or tabs.
A typical entry is:
With the hosts file containing the name for the network printer address, things can look a little friendlier -- note that the hosts file is really only a solution for small networks with a fairly static population.
Go into the Control Centre and under YaST2 modules/ Hardware/ Printer/, install a new printer. If your printer was connected through another computer, you would use SAMBA but here, we are printing through a printer server so select Direct TCP Port Printing and follow the instructions regarding the name of the server and so on -- YaST will search the network for any printer servers and display them so that you can choose the one you want.
The printer will be installed so that it uses CUPS.
This is done by typing http://localhost:631/ where port 631 is a recognised port number.
Note that the printer location is the name specified in the hosts file (in this case Diamond on 192.168.0.200) and the port is 9100.
From here, you can look at the queue status, print
test pages, kill jobs and so on.
This is the Printer server configuration screen, again on a browser although this is a different machine, one running Windows xp. This is done by typing http://diamond/ and from here the printer server itself is configured.
Linux -- Basic Image Processing with the Gimp
Rather than have a single MDI (Multiple Document Interface) within which are all of the components sit, the Gimp produces a number of small windows which, while seeming a little bit messy to Windows users, actually allows you to utilise the fact that under Linux, you can have multiple desktops and therefore, you can have different windows on different desktops as necessary whilst using the sticky button to make other windows appear on all desktops -- one use of this is grabbing screenshots which need to have one background but then can be carried over to another desktop where they can be processed without those processing windows getting in the way of the screenshot. But this program was not designed just for computer journalists getting pictures for their work.
In the screenshot on the right, you can see a selection of utilities:
Doing this will make a small version of the whole picture appear with the part you are looking at in a small window. You can move this around the image and the view in the window will move in real time.