hello everyone! i'm using arduino for the first time to control a domotic house for my school exams project.
i want to display temperature and some other values on the display but i have some problems.
I bought two of this: http://www.ebay.it/itm/310669842940?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_733wt_882
they are two LM 044L and in theory they have to work with the library <LiquidCrystal.h> as i found on the example ''Hello World'' but even if i try to use the displays with that example i have a problem.
The problem is that instead of writing what i want, the displays dysplay random characters.
i don't know why and i cannot even understand how it can be possible o.O
so please if you too had this problem help me to solve it because otherwise i'll have very big problems for my school exam 
thank you
fulvio Canestrari
It should be compatible with the LiquidCrystal library.
Could you check your wiring once more ?
Could you upload a schematic of how you have it connected ? or a photo ?
If the display is slow at starting up, sometimes a delay of 500ms or 1000ms in the sketch before the display is used will help.
Many of us had troubles getting a display to work. It is mostly bad wiring, or misunderstanding the R/W to ground, or 4-bit versus 8-bit trouble.
If you use a breadboard, it could have bad contacts.
Erdin:
Could you check your wiring once more ?
Could you upload a schematic of how you have it connected ? or a photo ?If the display is slow at starting up, sometimes a delay of 500ms or 1000ms in the sketch before the display is used will help.
Many of us had troubles getting a display to work. It is mostly bad wiring, or misunderstanding the R/W to ground, or 4-bit versus 8-bit trouble.
If you use a breadboard, it could have bad contacts.
Here is the picture. I checked the wiring at least 10 times. I tried putting delays but nothing... do you think that is possible that the problem is the lenght of the wires?
PS: i know that in the pic you can't see well the wiring but i followed the instructions on the examples..
I'm thinking: "flat cable", "5.0 Volt" and "grounding".
You use flat cable.
Could you use normal wires ?
The signals in the flat cable are coupled (capacitive and inductive).
If that is a problem, you could split all the wires of the flat cable.
Or is every other wire connected to ground ? It is hard to see.
Do you have a good ground connection ? and does the display get enough voltage. LCD displays often need 5.0V and not 4.5V.
Some explanation: Suppose you have two wires, side by side, for a meter long. When you send a pulse of 1A through one wire, the other wire creates a pulse of 1A in the opposite direction.
Thank you Erdin,
i replaced the flat cables with normal wires. now it works properly! maybe it gets a little less voltage than 5.0V because the brightness of the display is a bit low but anyway it is great seeing the display writing what i need ^-^
thank you very much again! 
Fulvio