MP3Car.com - View Single Post - Auto Dim Xenarc/Liliput with illumination wire from radio harness?

Kamakazie2 · 04-21-2006, 01:19 PM

Quote: Originally Posted by Scouse Monkey

its easy.

the pin-ins for the backlight inverter are onthe forum somewhere. I beleive it just takes a 0-5V signal for the dimming as there is pwm onboard.

All you need to do is intercept this 5V signal and have a circuit to chnage it when the headlights are on. Cant remember is 0V is ful or 5V is full.

If it is a PWM input (which I dont think it is) then you would need to have some kind of PWM (55IC circuit) that outputs a different signal depending on the healdights being on or off. You would lose the ability to control the brightness fromt he screen but it would allow you to have a thumb wheel or knob to do it instead as well as the headlight switched behaviour.

0v is brightest setting..

So it will operate like this
Monitor set at Full Dim

Lights are off: Relay is in the open position giving 0v to circuit causing backlight to be at max.
Lights are on: Relay is closed causing the origninal circuit of 3.3v (set at full dim) to dim the screen

04-21-2006, 01:19 PM	#5
Kamakazie2 Variable Bitrate Join Date: Mar 2004 Location: New Jersey Posts: 340	Quote: Originally Posted by Scouse Monkey its easy. the pin-ins for the backlight inverter are onthe forum somewhere. I beleive it just takes a 0-5V signal for the dimming as there is pwm onboard. All you need to do is intercept this 5V signal and have a circuit to chnage it when the headlights are on. Cant remember is 0V is ful or 5V is full. If it is a PWM input (which I dont think it is) then you would need to have some kind of PWM (55IC circuit) that outputs a different signal depending on the healdights being on or off. You would lose the ability to control the brightness fromt he screen but it would allow you to have a thumb wheel or knob to do it instead as well as the headlight switched behaviour. 0v is brightest setting.. So it will operate like this Monitor set at Full Dim Lights are off: Relay is in the open position giving 0v to circuit causing backlight to be at max. Lights are on: Relay is closed causing the origninal circuit of 3.3v (set at full dim) to dim the screen __________________ -Jack 2006 Chrysler 300C AWD IBM T30 Thinkpad / RoadRunner XMPCR/GPS/SIRIUS (RIP) HDRadio project: http://www.mp3car.com/vbulletin/hardware-development/93791-someone-here-has-able-crack-hdradio-car.html