Hello all,
First, let me say this is a great forum. I've been reading and searching for a couple of weeks trying to find out how to do what I want to do, and the wealth of information on here is staggering.
What I need is a little direction. I don't expect you to give me a fish, just show me where to start fishing...
What I have is a 2x24 Character LCD that I am installing in my car. What I would like to do is use my existing car dimmer lines to dim the backlight to match the other displays in my car (AC/Clock/Radio/etc...).
The backlight is being fed 3V (~50 mA) which is full bright.
I have two wires that dim the other displays in my car. When I turn the headlights on, one wire goes from 0 to 12V. This cuts the other display illuminations in half. (i.e. dims them to approximately 1/2 of "day" illumination) I would like to use this input to bring the input voltage to the LCD backlight down to ~ 1.5V.
The other line stays at 0V, until I start further dimming down the other displays (with the car dimmer control), and then it runs up to 9V at full dim. I would like to use this input to bring the input voltage to the LCD backlight down to 0V (or close to it).
I looked at using a voltage divider on each input line, and then a couple of ICL7660s to invert the voltage. But I can't seem to get them all to work correctly together to bring the 3V LCD input down to close to 0V. I'm (attempting to) simulate it all in CircuitMaker 6.2c.
Can anyone get me pointed in the right direction? I'd rather not get into timers and PICs if that can be helped. But if that's what it takes, then I guess I'd better start reading.
TIA,
-Jason
Just to clarify, the data input/control to the LCD is already taken care of (not by me obviously), I just need help with the backlight control.
First, let me say this is a great forum. I've been reading and searching for a couple of weeks trying to find out how to do what I want to do, and the wealth of information on here is staggering.
What I need is a little direction. I don't expect you to give me a fish, just show me where to start fishing...
What I have is a 2x24 Character LCD that I am installing in my car. What I would like to do is use my existing car dimmer lines to dim the backlight to match the other displays in my car (AC/Clock/Radio/etc...).
The backlight is being fed 3V (~50 mA) which is full bright.
I have two wires that dim the other displays in my car. When I turn the headlights on, one wire goes from 0 to 12V. This cuts the other display illuminations in half. (i.e. dims them to approximately 1/2 of "day" illumination) I would like to use this input to bring the input voltage to the LCD backlight down to ~ 1.5V.
The other line stays at 0V, until I start further dimming down the other displays (with the car dimmer control), and then it runs up to 9V at full dim. I would like to use this input to bring the input voltage to the LCD backlight down to 0V (or close to it).
I looked at using a voltage divider on each input line, and then a couple of ICL7660s to invert the voltage. But I can't seem to get them all to work correctly together to bring the 3V LCD input down to close to 0V. I'm (attempting to) simulate it all in CircuitMaker 6.2c.
Can anyone get me pointed in the right direction? I'd rather not get into timers and PICs if that can be helped. But if that's what it takes, then I guess I'd better start reading.
TIA,
-Jason
Just to clarify, the data input/control to the LCD is already taken care of (not by me obviously), I just need help with the backlight control.