“I like homemade gifts and if I have enough time for it, I’ll surely grab the opportunity to make one for someone. I was a bit uninspired for this one so I started looking online and got a few ideas and this is what I came up with.
So essentially what I made is a LED sign that turns on it rows of LEDs according to the amplitude of the audio signal being put into it, or the audio signal that its built-in microphone is picking up.
I think it’s very effective for its simplicity since all we are doing is amplifying the input signal, comparing it to some threshold values(both done with op-amps) and switching the rows accordingly with some transistors.”