Question about decoupling the power supply for LCD

Hi

I have just bought a 2x16 LCD and this serial backpack:

http://www.sparkfun.com/datasheets/LCD/SerLCD_V2_5.PDF

The datasheet says that when it runs with the backlight at full it draws ~60mA, and if I am not mistaken the Uno's max is 50mA. So considering that I am going to be running it along with several buttons and sensors I am definitely going to need an external power supply. Would running a 9V battery through a 7805 regulator be sufficient with the backpack? Or would I need to decouple it? Also do the capacitor values have to be exact or is some variation allowed?

Thanks

and if I am not mistaken the Uno's max is 50mA.

You are, you should not take any more than 40mA from a pin.

So you need to switch the backlight with a transistor assuming you want to switch it at all and not just connect it up to the +5V line.

Thanks for the reply Grumpy_Mike!

The backlight is already being controlled with a 1A BTJ Transistor.