[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.