how to enable backlight

johnmacd · Post by **johnmacd** » March 21st, 2006, 3:52 am

I have a LCD and I thought it had a backlight, but now I'm unsure it has one. How do you toggle the backlight on? I see a command on the action page, but how do you use it?

Also, I tried putting power directly to the blackight contacts on the screen using pins 15 and 16 and no backlight came on. I also have 2 contacts on the side labled A and K. I tried applying power to those and still no backlight. Then I tied 15 and A together and the same thing with 16 and K and still no backlight.

I guess I have no backlight? The spec sheet says there is a backlight.

_X7JAY7X_ · Post by **_X7JAY7X_** » March 21st, 2006, 6:33 am

What is the lcd? Does the specs say it has an LED or EL Backlight?

If it has an LED backlight, first of all how much voltage are you applying to it? Do you have a current limiting resistor, if not it could be damaged. Did you try reversing the voltage?

J

johnmacd · Post by **johnmacd** » March 21st, 2006, 3:24 pm

It says LED backlight. I put 5 Volts directly to it with no resistor. I didnt try reversing the voltage. Maybe I should try that. Should it come on right away, or does the backlight need to be turned on by the software?

_X7JAY7X_ · Post by **_X7JAY7X_** » March 21st, 2006, 3:50 pm

If you apply 5v directly to the pins it should come one, make sure you use a limiting resistor. An LED is a diode, it will only light in one voltage direction (polarized).

J

johnmacd · Post by **johnmacd** » December 15th, 2006, 4:55 pm

Well, it turns out that either I fried the backlight or this screen never had one.
I ended up just buying a new screen. I have the backlight working, but I dont understand how to toggle the baclight on and off. When I say toggle, What I really mean, is I would like to just press some key combination on the keyboard to turn it on and off. ie ctrl+b+l or something like that.
Once I see that I can turn it on and off, I saw that some people have added buttons. I'm gonna see if I can add a button to turn the toggle on and off. But I figured I'd be better off, just making sure I wired it all correctly and that I can turn it on and off.

Can anyone help me with toggling the backlight on and off?

thanks

johnmacd · Post by **johnmacd** » December 15th, 2006, 5:32 pm

to answer my own question. I'm going to try the hotkey plug-in found here: http://forums.lcdsmartie.org/viewtopic.php?t=193

heck, with this plugin, I think I might even be able to use girder and use my remote control to send the Ctrl-F10 command.