Residual speaker energy (what size resistor)

[FaT3oYCG]

hi im am planning on doing a little mod for myself with my psp that will be very cool if i get it to work, but i need to know some information first.

if i wire an led directly to my psp's speaker it is on because of the residual energy that the speaker outputs.

what i would like to know is what size resistor i would need so that the led wouldn't turn on with the residual energy, but it would do when for example i pressed a button on the dpad in the XMB.

i would also like to ask a question about the sound board that is sold on wiredinput.com, does this have to be used as a sound board, or can i use it as an amplifier for any power source?

hope you can help

Thanks

F@T3oYCG

[gr8npwrfl]

No you can not use the wired board as a general purpose amp

[FaT3oYCG]

No you can not use the wired board as a general purpose amp

i meant if i wired it to the speakers could it be used to power anything, within the limits ofcourse?

also anyone know or can test the resistor thing while the speakers are on full volume please.

thanks

FaT3oYCG

[gr8npwrfl]

The resistance always stays the same 8 ohms.

The impedance changes with the voltage and power input to the speakers.

Take a 1000 ohm potentiometer and put it in series with you led.
Set your volume to the level you want.
Adjust the potentiometer till the led goes out.
Increase the volume to make sure your led turns on then.

Remove the potentiometer and measure it with an ohm meter
That will be the value of resistance you need.

[FaT3oYCG]

The resistance always stays the same 8 ohms.

The impedance changes with the voltage and power input to the speakers.

Take a 1000 ohm potentiometer and put it in series with you led.
Set your volume to the level you want.
Adjust the potentiometer till the led goes out.
Increase the volume to make sure your led turns on then.

Remove the potentiometer and measure it with an ohm meter
That will be the value of resistance you need.

cheers, its not actually for an led but i thought it would be an easier way to find the right resistor strength needed.

*goes to buy needed parts and make schematic*

[ryan0]

you can't use a resistor to stop the led from being always on but rather use a capacitor.1st you must work out the resistance of the circuit while there is no sound output,then work out a capacitor size that will allow the led to pulse when there is sound output but not while there is no sound.Its called a "gain",they use them in the music industry for filtering out noise from songs,they use them for VU meter,not necessarily the same hardware or application,but it uses the same basic principle.
ryan0

[FaT3oYCG]

would a capacitor not release the energy when it fills up, i thought that capacitors hold the energy depending on their size and then release it all at once when they reach the level specified. i also thought a resistor, resisted the energy stopping the energy flow to whatever unless theenergy was over the specified level.

p.s. i have already said its not actually for an led, but i thought it would be easier to test it that way.

[ryan0]

would a capacitor not release the energy when it fills up, i thought that capacitors hold the energy depending on their size and then release it all at once when they reach the level specified

you just explained it all for me,once the volume reaches a certain level (depending on the capacitor),the capacitor will release it's energy thus lighting the led!