Tip 31 LEDS blink to music

you know how you can make an led blink to music with a tip31 , i was wondering, but didnt have enough spare cash (what can a 14 year old do) could you make an led display target shaped as in concentric circles of leds then apply resistors of increasing resistance from the inside out so that the light would "flare out" from the center as it gets louder and softer?

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robikazz6 years ago
yeah usually nobody has TIP31 but htere is tranzistor BD241 (and letter after it a, b, c) that makes the same trick ;]
jeff-o6 years ago
Unfortunately it's not that simple. If you did that, the LEDs would probably just brighten and dim as a group when the volume goes up and down. Most of the time, they'd probably be completely off.

A tip31 isn't very expensive... it the trouble in affording one, or getting one in the first place?
Algag (author)  jeff-o6 years ago
getting bunches of leds to do what i want is the hard part when saving up for school trips and whatnot
jeff-o Algag6 years ago
Well, maybe you could find what you need in some discarded electronics. Or, maybe your shop/electronics teacher can give you what you need.
Algag (author)  jeff-o6 years ago
that would work becuase i tear stuff apart alot :D but i would rather it look nicer and buy leds i just wasnt sure if it would work and about being as a group that is what i want but if i increased the resistance as i got towards the outside it would get dimmer as it got towards the outside correct
jeff-o Algag6 years ago
Well, see if you can find an old stereo from the 80s or something. It might have an LED VU meter in it, and a chip to drive the VU meter. That could be hacked to run dozens more LEDs, using transistors.

But the resistor ladder alone? No, that won't work like you want it to.
Algag (author)  jeff-o6 years ago
k thanx