[Edit: Problem is fixed from my perspective. Still no idea why contrast is different on arduino/boarduino though, when in usb power]
Christmas help needed!
Earlier I had my 16 pin 16*2 HD44780 LCD connected up to my Arduino, and all was working perfectly.
I soldered it to my Boardunio, and now my contrast is very low. (Barely visible, with my 10k pot turned all the way to one direction). My pot has ground/+5v on either side, with LCD pin 3 in the centre. I've also tried without the +5v connected to the pot; result is the same.
Oddly, if I power the boarduino with an external battery (rather than usb header) the contrast is *better* (but still bad) but then fades to the "bad" level.
I have current-limiting resistors (2*330 Ohm in parallel) on the backlight LED.
When I change to a blank sketch I only see very feint "blocks" on the top row of the LCD.
I'm desperately trying to finish this off before Christmas, so any help would be much appreciated!
Extra details (wire colours given for later pictures):
* LCD RS pin (4, yellow) to digital pin 12
* LCD Enable pin (6, blue) to digital pin 11
* LCD D4 pin (purple) to digital pin 6
* LCD D5 pin (grey) to digital pin 5
* LCD D6 pin (white) to digital pin 4
* LCD D7 pin (black) to digital pin 3
* LCD R/W pin (green) to ground
* 10K potentiometer:
* ends to +5V and ground
* wiper to LCD VO pin 3 (orange)
* Pin 0 unconnected, used to seed random(). Digital pin 7 soldered up and floating, for later use as a switch.
Working with arudino + back of breadboard soldering:
Set-up with boarduino: