Displaying two analog gauges onto an LCD screen.

I'm new to Arduino, but I've been working with java for the past five years as a hobby.

I want to read two analog sending units, both have voltages ranging from 0-5 volts, and display their output onto a 4.3" (480x272) LCD.

My questions are:
Is this a feasible task to write entirely in Java?
Can data be read from the input at a rate of 500ms, possibly faster?
What are the limitations of the video out? I'm thinking of using composite out.
Is a graphically pleasing interface possible?
Are there graphic libraries (other than TFT library)?
I can only find very basic 8-bit looking examples online.

Yea its possible but you wont be able to write it in java, it will need to be in C/C++.

Can data be read from the input at a rate of 500ms, possibly faster?

It can read the data a lot fast then that if you need it to.

What are the limitations of the video out? I'm thinking of using composite out.

You may want to look into the TVOut library, but it wont be in color. Or you can get a TFT lcd and make your own interface. I have a code that already allows you to make a working gauge, but it will require you to have a TFT that uses the UTFT graphics library.

HazardsMind:
You may want to look into the TVOut library, but it wont be in color. Or you can get a TFT lcd and make your own interface. I have a code that already allows you to make a working gauge, but it will require you to have a TFT that uses the UTFT graphics library.

I've looked around at these screens and the only ones I can find only the stand alone lcd. Do they make cases? I'd like to be able to mount it.

A case? not that i'm aware of, you will have to check the site that sells them. If anything you will need to make your own case too.

I have a code that already allows you to make a working gauge

.
Can you share this code please?

Go to the Other Software Development section, and look for my name. I made the gauge into a library called TFT_Extension.

Link to page HERE

SantaCruz:
I'm new to Arduino, but I've been working with java for the past five years as a hobby.

I want to read two analog sending units, both have voltages ranging from 0-5 volts, and display their output onto a 4.3" (480x272) LCD.

I've made "analog" displays on VFD displays. The idea is simple: Just convert your data to an angle. For example, if your data ranges from 0 to 255, convert that to something like -60 degrees to +60 degrees (angle).

Then take the sine of the angle times the radius (radius is the length of the gauge "needle"). Same with the cosine of the angle.

This is a polar to rectangular conversion, and it gives you the X and Y coordinates for the END point of a line. The START point of the line will be, of course, always in the same spot.

Then erase an old line and draw a new one each time the data changes. You now have a "gauge" who's "needle" swings a total arc of 120 degrees.

Finally draw an arc with tick marks for the gauge legend and you've got a meter.

A horizontal or vertical "tape meter" type of display is even easier. Just draw a long, skinny rectangle with tick marks as the legend, then erase and draw a line or a box who's horizontal or vertical position is relative to the data.

This is, of course, for a bitmap type of display. If you're using a "TV type" of display that uses video, then the above does not apply.