[Christian Doran] wanted some blinky goodness to go along with the tunes on his PSP. He built a VU meter circuit around a couple of LM324 op-amp chips and fit it into the UMD space on the back of the PSP. Using surface mount LEDs and some fine wire he lined up a string of indicator lights round the circle on the clear UMD cover. As you can see in the video after the break, the back of the case now pulses along with the music.
[Christian] notes that building the VU circuit around an LM3915 would have been much easier but he’s working with what he has on hand. Looks like he achieve the effect he was after. If you want to learn a bit more about how the op-amps work, take a look at the tutorial from our links post.
[youtube=http://www.youtube.com/watch?v=ePNwQOe-FbI]
how do you play umd’s?
you dont
@googfan
voodoo
It’d be cooler if it didn’t blink so much, just smoothly went up and down like the UI on the front…
Also It’d be neat to see this used by a game.
@Mikey
capacitor on the input? … like a 1uf with an adjustable 15 turn 1k resistor to limit input current might work
1uf might be to big tho
@BiOzZ — that’s over my head, Long time developer, complete newbie at electronics. I assumed this was software controlled, but after re-reading I see that he’s using op-amps. Is this directly connected to the audio output? So… anything that spits out sound will fuck with the lights on the back? Lame.
@Mikey: o.O’ How is that lame? You were saying it would be neat for this to be used by a game; well, anything using the speakers uses the leds. He probably has a switch to turn it on and off, and it could be easily added if he doesn’t.
Not my style but it looks neat.
Looks like he achieve the effect he was after.
typo * achieved
;-)
pretty cool, doesn’t look finished though, lights spaz too much (I forget the proper term >_<) still cool, gotta love the PSP hackers, and now I have another reason to get a 2000 over a go.