Okay so there is many LCD's to pick from with many different price tags...ebay LCD's are the cheapest but are they hard to code? Can i use and LCD and code it easy or find the code ? How does it work
I want a serial LCD or and LCD with the serial backback, something like 20x4 which i saw for cheap on ebay but sparkfun has them but at much higher price
If we're talking about monochrome text LCDs, there are two common types. The parallel interface types are cheapest and easy to drive using the LiquidCrystal library. However, they require 6 Arduino output pins to drive them. The serial interface ones cost more but need only 1 pin. Typically you would use the SoftSerial library to avoid tying up the hardware serial output pin.
You don't get support from ebay sellers as much as from sparkfun. Again, sparkfun is overpriced to some extent.
As a hardware designer myself, I can speak for similar individuals. Pricing a serial back pack around $20 is not too bad, considering the time and effort to do the hardware and firmware design and sell these in small quantity. I have designed a serial backpack myself except it also comes with keypad and buzzer and a lot better firmware. The parts alone are not so far below $20 range when all I can do is ordering 10 PBCs or 10 anything at a time. sparkfun is a larger company and they can order by hundreds or thousands, which reduces cost by a lot. That is a different story:)
Is this what you were comparing with ebay items?
Doesn't look so bad. The module is made for sparkfun so they must have ordered lots of them.
Remember the thing has an arduino-like processor on board running programs so you canaccess the display with serial.
yes im looking for a blue with white monochrome text LCD that can be connected by serial and not take up all the pins but at same time can be coded ..sparkfun has the 20x4 that i want but only in green..so where else can i find a cheap LCD that i can easily code basically ?
I buy LCDs on ebay. chinaecomponents is my personal favorite ebay store. To save pins, I designed a serial LCD keypad panel:
You run this thing on two pins (serial) up to 115200bps if you have a hardware serial to connect it with.
If that is what you want, you can get just the back pack version and add your own lcd. The backpack is way better than any serial diplay backs on the market. There are over 2,200 lines of code on the panel running every aspect of it, LCD, back light, wrapping and scrolling, long messages or menus using arrow keys, multi-tap on the keypads, buzzer tones, LEd indicators and more. Other serial LCDs don't have no keys and probably have up to 200 lines of code. This panel also has an on board menu to control the panel's properties.
If you are lucky and industrious, I've successfully sampled LCDs before.
Okay so there is many LCD's to pick from with many different price tags...ebay LCD's are the cheapest but are they hard to code? Can i use and LCD and code it easy or find the code ? How does it work
The character mode LCDs that you are interested in all use the 14-pin parallel interface originated by Hitachi. They require at least six microprocessor I/O pins to function and the LiquidCrystal library does a good job with virtually all of them.
I want a serial LCD or and LCD with the serial backback, something like 20x4 which i saw for cheap on ebay but sparkfun has them but at much higher price
The serial versions of the character mode LCDs are based on a parallel device of the type mentioned above. Many of them employ a dedicated microcontroller to convert the serial information from the Arduino into the parallel information required by the display. Unfortunately there is no single library that will deal with the various serial implementations. You are stuck with the library that may or may not come with the device and which may or may not work reliably. This is more likely to be a problem if you buy a general purpose serial backpack and use it with an eBay LCD. If you buy a backpack/display combination it will probably work properly but there is the possibility that some control functions that you want may not be implemented.
Some serial LCD implementations do not employ a dedicated microcontroller but instead use an I/O expander or cobble up a shift register to do the job of an I/O expander. This gives you the advantage of lower cost at the expense of some additional programming. Since the programming is done on the Arduino you at least have the opportunity to make sure that it is coded properly and you can implement all of the control functions available in the LCD controller. I believe that there are some LiquidCrystal compatible libraries available if you take this approach.
Don
When buying from ebay, at least locate the spec sheet of the display and read it before placing an order. If the seller provides no spec sheet, don't be fooled by price 
well thanks everone for the information, in short terms i need to buy a serial LCD already paired and the easiest way would be paying the money for sparkfun basically or does anyone know of a site that sells the 20x4 blue/white paired with a backback ?
This one is generic enough and cheap. The spec sheet is identical to what I use for my LCD panel or back pack so it should work on my back pack.
I didn't find any guarantee on adafruit's back pack, which has no microcontroller and is not serial compatible. Apparently you looked at sparkfun (I did too but a while ago) and they don't have it.
This one seems to be blue too. Never had one myself but seems to have more function than a simple serial LCD.
i bought 3 of this http://www.ebay.com/itm/NEW-Character-LCD-Module-Display-LCM-1602-16X2-162-blue-/220604499525?pt=LH_DefaultDomain_0&hash=item335d0d8645#ht_4080wt_956 and i paid ~10$ including shipping (~7$ was the shipping cost) they all work perfect with my arduino and the LiquidCrystal library
if your are worried about the number of pins you can try this Arduino Adventures: Controlling an LCD Display with a Shift Register didn't tried it myself yet but i will
putyn:
i bought 3 of this http://www.ebay.com/itm/NEW-Character-LCD-Module-Display-LCM-1602-16X2-162-blue-/220604499525?pt=LH_DefaultDomain_0&hash=item335d0d8645#ht_4080wt_956 and i paid ~10$ including shipping (~7$ was the shipping cost) they all work perfect with my arduino and the LiquidCrystal libraryif your are worried about the number of pins you can try this Arduino Adventures: Controlling an LCD Display with a Shift Register didn't tried it myself yet but i will
OP wanted 20X4 displays. Never the less, thanks for the good deal! My personal experiences with over 2 dozens of white/blue displays (2 sources) are that they are sluggish, so are the red/black ones.
Thanks everyone for the help and that great ebay find there, really cheap.. now the problem is that yeah i wanted 20x4 and blue/white but wait are they really sluggish ?? i want white just because its more eye pleasing but if its sluggish then i might take that idea back
anyone else find them sluggish?
The blue display being slow was my own observation and was probably seen by few others. So unless you get a green and a blue one side by side, you can't tell. I suggest you go ahead and get the displays then play with one or two displays. Then buy a serial back pack for your favorite display and marry them together.
thanks i think thats what i might do and for the price i might just go with a 16x4 for now
stupid question: if i upload a sketch to the board and then dont want it must i go and remove it some how ?
If you don't want a sketch, just load a different one, which will replace the first one.
I would start with a 20x4 instead of 16X4.
I was thinking this backback http://www.ebay.com/itm/I2C-Serial-LCD-controller-keypad-control-Arduino-/230658504297?pt=LH_DefaultDomain_0&hash=item35b4517669
with this display http://www.ebay.com/itm/HD44780-20x4-LCD-module-Blue-backlight-Free-pin-header-/320537704483?pt=LH_DefaultDomain_0&hash=item4aa1893823
good bad ??
Maybe the back pack + LCD (seems to be standard one).
The complete package uses some custom library to drive so you could be stuck if no one helps you with code or no future update is provided. I am afraid it is a cheap I2C extender-driven thing like adafruit has. I would not buy it.