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Trouble blinking leds with TIP31 Answered

Hello everybody, I am trying to make a blinking circuit to hook up to the LED strips in my car so they blink in sync with the bass. 

I have made a circuit following some instructable here, I can't recall which it was. Anyway, I'm pretty sure the schematic is correct, because the leds blink.

Now two problems arise: I have hooked them up to the subwoofer out of my radio ( a Kenwood kdc something), and after enabling it I was told to put a speaker coil in series to increase the resistance, in order not to fry the channel. Is this right?

Next, the leds don't quite blink, but they pretty much stay on all the time, with very little variation, I suppose because the sub out gives out quite a high voltage, so the transistor does not open the enough for the leds to blink properly. I was thinking of putting a resistor/potentiometer in series with the signal coming from the radio, in order to reduce the voltage and have a better blinking effect. What do you think?

Thanks in advance, peace :)

7 Replies

user
icengBest Answer (author)2014-11-18

I supply circuit designs because you do not.

Peace or the World in pieces......

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user
en_rov (author)iceng2014-11-24

This is similar to the circuit I made, except for the fact that I didn't use another TIP31 to amplify the channel, since I think the sub out provides a decent amount of voltage.

The point is: the LEDs stay on too much, and they don't blink much, I suppose because the voltage is too high for the transistor to open the circuit enough.

What should I do?

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user
iceng (author)en_rov2014-11-24

Now you have enough gain to add series or parallel RC filters to make your led respond to high or low frequency.

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user
en_rov (author)iceng2014-12-05

Thanks. I'll go for this :)

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user
rickharris (author)2014-11-18

show us the circuit you built for a start.

What exactly are you tryimng to do?

In general the issues tend to be that the LED isn't off long enough for you to be able to see it.

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user
en_rov (author)rickharris2014-11-24

See above for the the circuit :)

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