This allows us to create a level sensor that is safe for use with any liquid, this one will be used in a buggy with gasoline (petrol).
One plate is hooked to ground. The other connects to pin 23. There is a 820K ohm resistor from pin 22 to 23. The sensor works by charging the capacitor (the water bottle) and measuring how long it takes to drain through the resistor.
Step 1: Parts
2. Arduino, I'm using an Arduino mega but a standard one should have just enough pins.
3. LCD character display.
4. Some odds and ends including some wire and a 1MΩ resistor.
5. A computer, you know, that thing your using to read my instructable with.
Step 2: Connecting the LCD and letting your creation talk to the world.
Your lcd has 16 throe hole solder pads so the first thing is to attach some pins. If your patent then I recommend purchasing a header like this http://www.sparkfun.com/commerce/product_info.php?products_id=117. But if you want to get done as fast as possible (like me) then you can use wire.
Simple cut 16 pieces of wire at about 1/2" (13mm (longer is okay)). Then solder them to the board.
Step 3: Connecting the LCD Continued.
Pin 1 Ground
Pin 2 +5 Volt
Pin 3 Contrast adjust
Pin 4 RS
Pin 5 R/W Goes to Ground
Pin 6-14 Data
Pin 15 Back-light Power
Pin 16 Back-light Ground
Step 4: Data Lines
It doesn't mater what pins you use, but I recommend following the schematic.