I want to connect a mobile screen to the Raspberry PI in the cheapest way possible. I don't mind if I attach a touch screen (if it's possible) to it or an old laptop screen.
How would I be able to connect a old Toshiba laptop screen to the Raspberry PI?
There's no easy way to - your laptop screen has a LVDS connection which needs a driver chip specific to it, your raspberry pi has a SPI video interface onboard (which there hasn't been any use for) as well as a composite out. You'd need to get a board that takes in a composite input, and output to LVDS - which probably exists - try the comments of this hackaday post for ideas - they suggest a company called NJYtouch.
Alternately you can get a small LCD that will take in a composite input of some sort.
Use a lapdock. You have to find one cheap, second hand, then make up some cables. I managed this fine with an Atrix lap dock. I got a second lapdock which was an lapdock 100 and this was not as good. I could not get the keyboard layout correct. You need to make up some cables. I think the best approach is to remove/short the fuses on the USB port of RPi and feed power into it from the USB port as well as the usb key board. I have not done it that way yet. I tried the original method which is a spliced cable with power on the micro USB power port and keyboard on the RPi's USB port. Google this. Adafruit and others have made videos on how to do it. Be carful you get a keyboard for your region. Some stories of brits ending up with Norwegian keyboards with keys in the "wrong" place. I think the boxes have the region flag on the front and you can usually see this in the photo on ebay. Some offers on other sites too as this is an obsolete device. http://www.youtube.com/watch?v=yZkz_a52I6s
For a really cheap solution, purchase a small LCD. Most of them are for rear backup cameras in cars but they are so cheap and would work perfectly for an RPi. Most of them take a composite input. A few have touch capabilities but those are pretty expensive. Here's an example from Amazon.
I have a laptop that is about 2 years old, and the screen is getting very dirty, full of smudges from my fingers (yes, I know, I shouldn't touch the screen). The screen is not glass, it's soft and rubbery.
How would you go about cleaning the screen without ruining the laptop or the screen? Would I need to disassemble the laptop? And should I use some chemicals?
Use a microfiber cloth with distilled water if you're worried about ruining the screen, absolute basics.
To cut any fingerprint grease though, vinegar and water is also good with a microfiber cloth.
What I always use is a soft cotton t-shirt that is slightly damp.
Helpful tips on how to clean a laptop screen here
Personally I use rubbing alcohol and a paper towel. Some places say alcohol will yellow your screen, but I've been using it for my current laptop now for over 5 years... and no yellowing has occurred.
It MAY yellow your screen if you use it EVERY day for 10 years or something, but used occasionally, it is no problem.
Alcohol has the added benefits of being VERY quick-drying and not harming electronic circuits if a little gets on them.
I turn it off, then use a small bit of water along with a cloth that you get with glasses that is for cleaning lenses - always does the job!
There is a lot of debate on this.
I used Windex for years on my CRTs, didn't seem like it did any damage to them, but going with the flow of opinions from other people; don't do that.
I went out to Radio Shack and purchased a screen cleaning kit for $20. They truly have turned it into an art form. If it is more than just finger prints, I think you would something a little "stronger" than just water (not Windex).
If you're wearing glasses, anything that cleans them will also clean your screen.
My own favorites are alcohol-saturated glass-cleaning wipes.
After I clean my glasses, I finish by cleaning the screen (if necessary).