Go Down

Topic: LCD Backlight issue (Read 1 time) previous topic - next topic

liudr

Jacking the post along a different direction, has anyone used PWM pins to light up back light at different lumination? I heard that it is what lcd screens do to adjust brightness.

pwillard

since it is just a cluster of LEDs... PWM should not be a problem.

I also disagree about it not being much of a load on a pin... you need to ISOLATE it drive it with a higher current device... unless you don't mind having fewer pins on your arduino.

floresta

Quote
You'll probably find the backlight uses less power than the arduino...


Quote
Actually, that's a little less current than I expected, given the light it throws out...


I hope you measure the current that your backlight draws before you try driving it directly with an Arduino pin.  I looked at a random data sheet and saw a typical backlight current of 180 mA.  That's almost 5 times the current rating of an Arduino pin.

Don

econjack

Yep...all is well.

BTW, when I upload a sketch to the Arduino, the LCD cycles in sync with the upload LED on the board. What is the Arduino IDE doing during the upload to cause this? Does it have a meaning, or is it just a byproduct of the IDE? Just curious.

Go Up