Help with VU meter by TMT

[ccyyss]

Hi folks,

Firstly, with credits to TMT for the wonderful job with the VU meter, most impressive mod IMO.

Building the circuit, I found myself stuck reading the audio input. I tried to e-mail TMT however I do not seem to get any response.

With reference to the diagram below, does anyone know what those LSP1-LSP6 are? Simply can't figure them out.



Thanks in advance.

Best Regards,
Josh

[FOOKz™]

I think that they are just test points to check and see if the circuit is working correctly. I really don't have any other guesses to what they are exactly besides that. If you look at it a bit more LSP3 and LSP4 are redundant and are connected to the same wire... LSP1 is connected to 0v.


Just try to build the circuit and see if it works.

Hope that helps!

[ccyyss]

One more question, what's the capacitor's value after the 600k resistor from the audio input?

I'll post the results asap =D

Regards,
Josh

[FOOKz™]

looks like a 10nF cap.

that cap's value isn't critical, i say a value between 1uF to 0.1uF (100nF) will work. It MUST be electrolytic (capacitor with plus and minus on it), yeah you can get away with a ceramic but that will add noise to the circuit.

[ccyyss]

Everything fits together nicely, and indeed the capacitor's value didnt really matter, the readings are nice, but well, seems a bit slow compared to the pulse from the music, small clicks could not be projected, as the matter of fact, the readings became zero as soon as the volume is at 1/2 and it'll be running on the 'animated displays' meant for silent/earpiece mode.

I'm thinking if I were to reduce the 600k resistor, will it be more 'responsive'? and i wonder if the capacitor's decay value can be decreased.

Nevertherless, it works like a charm and lights to the beats when all elements are aligned here, haha!

[FOOKz™]

yep, 600K is very high so reduce it to about 330K to 200K and it will be more sensitive.

[hyper999]

Stick a Pot in instead of the resistor and that way you can tweak it to fit your needs