solar lamp with sound detection -adjusting sensitivity

[Lutin]

Greetings from France,

I bought a solar wall lamp with sound detection, but I have to make a lot of noise to turn it on.
Could anyone help me out with finding out how to increase the sensitivity? My skills in electronics are close to zero...

Here are pics of the PCB.



Cheers!

 

[Lutin]

Nobody?

 

[Nigel Goodwin]

Nobody?

You need to post a circuit diagram.

 

[nickelflippr]

Looks like a LM358 (U3) op amp is used to amplify the electret mic in this circuit. Check out the **broken link removed** for the AC coupled amplifier circuits and possibly a low pass filter. Draw up the resistors in relation to the pinout diagram of the LM358 for the circuit board ,and match up to the reference circuits. A high value trimpot could be added in place of the gain resistor, to vary the sensitivity. For instance the inverting amp the gain is Av = Rf/R1, with Rf being the high value resistor or trimpot. The surface mount resistors markings.