You hook the old phone's LCD screen to the computer USB of course!
In this project we're going to communicate with a Nokia 3310 LCD display over USB! How are we going to do that? We're going to connect the LCD display to an Atmel ATmega8 micocontroller and talk to it using the SPI, then connect the ATmega to a PC using V-USB.
The Nokia 3310 LCD display is easy to find, and has a very well documented interface, so it's perfect for hobby use! Not only that, but we're going to use V-USB (Formerly AVR-USB) as our USB driver on the AVR chip. This makes the project very easy to pull off the ground.
V-USB is very slow, so you cannot do any fancy animations this way, but is perfect for updating the display with text! Also, when using USB, you can use this on pretty much any computer. It does require libusb though, but libusb is cross platfrom, so that shouldn't be a problem. Or, if you're really hardcore, you can write your own driver for this project (This is way out of the scope of this instructable)!
What uses does thing have?
As I mentioned, V-USB is pretty slow, so it's best for sending text. Even through this is a little drawback, there is still a lot of stuff you can do with it!
Display RSS feed, Twitter updates, weather, temperature, free disk space, unread e-mails.
You are not limited to just display text though. If you're feeling really fancy, you can make a 1-bit picture slideshow!
Only your imagination (And the slow speed of V-USB) limits you :)
What features does the code have?
With the code you get from this Instructable, you get:
* Built-in font and support for writing ASCII characters
* Character wrapping (Prevents characters from being printed over 2 lines if end of display is reached)
* USB connected and powered
* Easy to expand
The code is open source (Both firmware and host software), so you're free to do whatever you want with it. (This only includes the software I have written. See the license for V-USB for further use of that, same goes for libusb. Both licenses are included in the source files.)
This project is loosely based on Raphnet's Multiuse PCB, V-USB's PowerSwitch and DharmaniTech's Nokia 3310 LCD routines library.
If you have problems downloading the attached files, I have mirrored them here: Atmega8_LCD.rar and LCD_Screen.rar