I bought the following:
I2C backpack (YwRobot LCM1602 IIC v1) LARGE 20x4 LCD (JHD762M5) (http://tinyurl.com/ar99rj2)
It didn't work out of the box, but a little searching led me to this, which works fine:
[SOLVED] SainSmart/YwRobot I2C LCD works well http://arduino.cc/forum/index.php?topic=106655.0
The problem is that I really want to be able to turn down the backlight brightness and I do not seem to be able to do anything more than turn the backlight on and off using "lcd.setBacklight()". Is this a limitation of the I2C, or the LCD (either? neither?)
I do not need to control the brightness via software (I just figured that this would be the simplest solution), and I would prefer not to set up PWM control. I would be happy to just put a pot on it and be done, but when I researched that solution I read that it is not the preferred method, and to use a transistor... I got a bit confused at that point. Can someone please point me in the right direction regarding how to proceed? Is the solution as simple as putting a pot inline at pin 15 or pin 16.
This is a very large display. I measured about 90mA current draw with the screen lit up, so if I do go the PWM route I think that I will need to use a transistor. Right?