sound sensitive LEDs

JoeKnowsBasebal · 19th November 2007, 02:41 AM

i'm a noob here. i know a little about electronics cause i used to install car audio/video/alarms, but i don't know all the equations for the electronics or anything like that. basically i know resistors and wire guages.

anyways... i want to wire a few (2 or 3) LEDs into my car that get brighter as i rev up my motor. i want to place them inside the hood scoop on a Camaro SS. I've wired LEDs in a car before, but i've never done a sound sensitive wiring. I want them to get brighter as the engine gets louder.

what are the parts i need and maybe a simple wiring diagram to help me out. just let me know the part names (like the device that recognizes louder or softer sounds) and maybe how much voltage i should have running through everything.

thanx in advance.

ocool_15 · 19th November 2007, 03:13 AM

If you are just wanting it to work off a mic look up lm3915, lm3916 Ic's. There are kits based on those chips that should do what you want.

zigzagflux · 19th November 2007, 04:58 AM

Would seem easier, simpler, and cheaper to use a tach signal, and use a frequency to voltage converter to light your LED's.

Mics are relatively expensive in comparision, and won't work very well under the hood, IMO.

JoeKnowsBasebal · 19th November 2007, 05:13 AM

can i get those at a store like Radio Shack or would they have to be ordered off the internet?

JoeKnowsBasebal · 19th November 2007, 07:05 AM

i'm still thinking about going the mic route. does anyone have a part number for a small mic that i could use with an LM3915 IC?

Perry Babin · 19th November 2007, 11:39 AM

The LM391x ICs are bar graph drivers and would be a good choice if you want to light more LEDs at higher volume. If you only need to make a group of LEDs brighter, you could use a mic to drive a simple amplifier circuit. The amplifier would make the LEDs brighter as the volume increased.

I don't know if this would work well without filtering. The mic would pick up any sound. Going down the highway, wind noise would make the LEDs light up.

Digikey has large selection of condenser mics that will work.

19th November 2007, 02:41 AM	#1
JoeKnowsBasebal diyAudio Member Join Date: Nov 2007	sound sensitive LEDs i'm a noob here. i know a little about electronics cause i used to install car audio/video/alarms, but i don't know all the equations for the electronics or anything like that. basically i know resistors and wire guages. anyways... i want to wire a few (2 or 3) LEDs into my car that get brighter as i rev up my motor. i want to place them inside the hood scoop on a Camaro SS. I've wired LEDs in a car before, but i've never done a sound sensitive wiring. I want them to get brighter as the engine gets louder. what are the parts i need and maybe a simple wiring diagram to help me out. just let me know the part names (like the device that recognizes louder or softer sounds) and maybe how much voltage i should have running through everything. thanx in advance.

19th November 2007, 11:39 AM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	The LM391x ICs are bar graph drivers and would be a good choice if you want to light more LEDs at higher volume. If you only need to make a group of LEDs brighter, you could use a mic to drive a simple amplifier circuit. The amplifier would make the LEDs brighter as the volume increased. I don't know if this would work well without filtering. The mic would pick up any sound. Going down the highway, wind noise would make the LEDs light up. Digikey has large selection of condenser mics that will work. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

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19th November 2007, 03:13 AM	#2
ocool_15 diyAudio Member Join Date: Nov 2004 Location: sk	If you are just wanting it to work off a mic look up lm3915, lm3916 Ic's. There are kits based on those chips that should do what you want.

19th November 2007, 04:58 AM	#3
zigzagflux diyAudio Member Join Date: Oct 2006	Would seem easier, simpler, and cheaper to use a tach signal, and use a frequency to voltage converter to light your LED's. Mics are relatively expensive in comparision, and won't work very well under the hood, IMO.

19th November 2007, 05:13 AM	#4
JoeKnowsBasebal diyAudio Member Join Date: Nov 2007	can i get those at a store like Radio Shack or would they have to be ordered off the internet?

19th November 2007, 07:05 AM	#5
JoeKnowsBasebal diyAudio Member Join Date: Nov 2007	i'm still thinking about going the mic route. does anyone have a part number for a small mic that i could use with an LM3915 IC?

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