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Anybody got a few mins to spare and make £15 (or the local equivalent) ?

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New Member
Hey guys, I'm new here and relatively new to the whole electronics scene in general, and need to build a certain project. Without going into too much detail as to why, I need a circuit that converts a sound input via a mic to a visual output, via 5 LEDs.

It would ideally be small and constructable on a piece of breadboard, and be made of parts purchasable from this place.

It would have an onboard mic, an onboard battery, and the five LEDs would light up depending on the loudness - if a small volume is detected, only one would light up; if really loud, all five light up. Also a sensitivity adjustor would be crucial.

If anyone could draw something up for me, a circuit with all the parts I'd need to buy (with links to their page on the site I mentioned above) I'd be eternally grateful and would gladly send some money through via paypal to the helpful guy :)

I'd offer more than £15 but alas I'm a student and have little more to my name X[

Thanks in advance to anyone willing to help out a poor soul :)


New Member
hey guys, sorry to bother again, but I'm stuck :(

I managed to get all the parts needed (the individual parts, not the kit) and am struggling to put the bits together on a breadboard.

I don't know what to make of the battery - where does the negative terminal connect to? Same with number 2 in the attached image.

And the microphone? Physically it has positive and negative terminals, but right beside the negative terminal is a 'bar' kind of thing. According to the circuit diagram, it should just connect to the negative terminal, so should I just solder the two together?

Thanks again :eek:


The microphone may have a connection to the metal casing next to the negative pin. If yours is not connected then I think you should connect it to the negative pin as it will help to screen against hum.

I don't know exactly what you meant about the battery connections as your image attachment did not attach.
I think you meant that it was not clear where on the diagram to connect the battery negative lead to.
It connects to the same place as the microphone negative pin.

I just saw your circuit and just connect points 1,2 + 3 together
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Well-Known Member
Most Helpful Member
There may be a problem with the circuit. The maximum level LED takes current via 4 BAT85 Schottky diodes. That lot will add up to about 1.4 V drop, only leaving 1.6 V across the LED. That is at best marginal and the maximum level LED won't work unless the battery is new.
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