car light dimmer

Astro Power · 23rd May 2005, 06:51 PM

hi all.

i want to build a good dimmer to my inside light of in my car...

when i close the door... the light is terns off progressively....

thanks...

by the way.....the lamp is 10W 12V.

tamir

Astro Power · 24th May 2005, 10:45 AM

http://users.otenet.gr/~athsam/dome_light_dimmer.htm

i build this and is only make a delay....... it is no work like a dimmer.

tamir

Eva · 24th May 2005, 03:28 PM

Pulse width modulation techniques are required in order to dimm a 12V light bulb without wasting a lot of power. Modulation frequencies may be as low as 100Hz to reduce EMI radiation

There are a lot of analog PWM ICs suitable for doing that. The good old SG3535 and TL494 may be used, ramping its duty cycle with a capacitor charged or discharged through a current source

Another approach may be to do the PWM and control logic in software using a simple low-cost microcontroller. I've succesfully used the PIC12C family from Microchip for several custom automotive applications. Sometimes going PIC saves a lot of development time in comparison with the equivalent analog solution

23rd May 2005, 06:51 PM	#1
Astro Power diyAudio Member Join Date: Sep 2004 Location: Binyamina	car light dimmer hi all. i want to build a good dimmer to my inside light of in my car... when i close the door... the light is terns off progressively.... thanks... by the way.....the lamp is 10W 12V. tamir

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24th May 2005, 10:45 AM	#2
Astro Power diyAudio Member Join Date: Sep 2004 Location: Binyamina	http://users.otenet.gr/~athsam/dome_light_dimmer.htm i build this and is only make a delay....... it is no work like a dimmer. tamir

24th May 2005, 03:28 PM	#3
Eva diyAudio Member Join Date: Oct 2003 Location: Near the sea	Pulse width modulation techniques are required in order to dimm a 12V light bulb without wasting a lot of power. Modulation frequencies may be as low as 100Hz to reduce EMI radiation There are a lot of analog PWM ICs suitable for doing that. The good old SG3535 and TL494 may be used, ramping its duty cycle with a capacitor charged or discharged through a current source Another approach may be to do the PWM and control logic in software using a simple low-cost microcontroller. I've succesfully used the PIC12C family from Microchip for several custom automotive applications. Sometimes going PIC saves a lot of development time in comparison with the equivalent analog solution