I just ordered one of these last night. It will mount onto the back of most common LCD modules. You can select either I2C or serial communications mode and it has built in keypad scanning interface for a 4X4 keypad. Lots of features your just a few bucks.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=170302846714
Lefty
Do you know if it is made so that you can have more than one of them on the same I2C bus ?
nice thing.. sounds really interestering
On a side note - wouldnt it be nice to have some sort of.. community project to make such a thing of our own? Something Breadboard ready? I know we have in the playground a hd44780 to I2C code (for a chip i dont get here ><), so who would like to build upon this on a module like the one in the link?
There was a discussion on this topic a while ago although it gone quiet: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1200398529
The Eagle files for the board discussed above are in sourceforge: http://openlcd.sourceforge.net/
That design uses an ATmega168 chip and it may not end up much cheaper than the ebay board that Lefty found.
Do you know if it is made so that you can have more than one of them on the same I2C bus ?
The online manual for the ebay board says that the I2C slave address can be changed, so I would think one could use multiple boards on an I2C bus.
Do you know if it is made so that you can have more than one of them on the same I2C bus ?
Yes you can reassign it's I2C address: From data sheet
"Each device must have its own unique address (ID). The address range is from 'A' to 'Z' (HEX
from 0x41 to 0x5A). Default address shipped from the manufacture is 'L' (0x4C).
The address can be easily changed by send the command “Set the new device address”.
Lefty
Lefty, I answered that in the previous post 
Nice find on the board, interested to hear how you get on with it
Yes please post results. This seems to be a reasonably priced solution the a problem that has been in the forum serveral times: how to drive multiple displays.
Ive got one , but have just been using it as a serial device.
It works realy well.
I was just thinking about ordering another on when I saw the other post by JakesSA.
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1235195958
Who has posted how to make your own for very little money.
Hes even modified the 4bit lcd library to work with it.
Looks realy interesting.
I think Ill give it a try and switch to I2C.
Gordon
Well the serial LCD controller arrived today and I quickly wired it up to my breadboard to a USB serial converter module and tested it out with my windows terminal program. Everything worked out of the box.
Only initial problem I came across is that the serial controller has male pins for the 18 pin connection to the LCD and my LCD has male pins also, so that was a no go. So I chopped up a 40pin IC socket and solder it back to back as a female to female connector so everyone could play nicely together.
As a coincidence I had ordered a 4X4 keyboard matrix the same day I order the LCD serial controller and it to arrived the same day, it coming from Hong Kong. It has a connector that hooks right up to the serial control, no wiring changes needed. The controller has an interrupt pin that your micro can scan or interrupt with when there has been a key button pushed and then there is a serial command you send to the controller that then sends back the value of the button (0x01-0x10) via the serial interface. Very cool. This whole setup is a real pin saver for the Arduion for all the functions it can do. The serial controller has quite a few graphic commands that can allow one to do quite a few things with.
Anyway highly recommended, it's a good price, does what it says, can work as serial or I2C and the built in matrix keypad scanner makes for a super low cost terminal interface for your Arduion applications.
Here is the matrix keypad I bought:
Lefty
Hi Lefty, that link doesn't work for me.
Hi Lefty, that link doesn't work for me.
Fixed the link I hope. Your links are OK but there priced somewhat higher and the I2C controller doesn't have a TTL serial mode and only handles a 4X3 matrix keypad.
The keypad I show is real thin, .040 inches thick, 3" tall X 2.7" wide. It's designed to be glued or double tapped to a flat surface and only requires a .012" X 1" slit to pass the flat flex cable trough. No sign of contact bouncing so the controller is handling that well. Good cheap keypad, decent quality for the few bucks.
Lefty
The fixed link works, thanks. I wasn't recommending the ones I linked, its just that they were the only ones I saw - yours looks a very good price.