I bought a sound switch from aliexpress but was to sensitive to slightest sound. I came across a comment showing a modified circuit by adding a potentiometer which claimed to be able to control the sensitivity of the microphone at switching on the circuit.. Problem is i do not know where should i attach the potentiometer to.. would be grateful is someone could help me out. Thanks. I have attached 2 photos. 1st is original circuit. 2nd is the modified circuit. Looks like the potentiometer is attached to the L393 but not sure which pin..

MOD: processed your images, to make them readable.E

 

Do you have a link to the original part?

 

MYR 5.05 31%OFF | Urijk 220V 50Hz LED Sound Operated Switch Energy Sensor Voice Control Lamp Acoustic Sensor Switch
https://s.click.aliexpress.com/e/ElvwLdA

 

looks like he removed the LDR on the PCB from pic 1 to pic 2... If you added a potentiometer one leg of the LDR and to one of the fixed ends as per below and connected a variable end to one of the holes

like this:



Try a 10K potentiometer

 

Well, that was helpful
Not!
(Update: was only referring to the glut of information on the aliexpress listing)

 

looks like he removed the LDR on the PCB from pic 1 to pic 2... If you added a potentiometer one leg of the LDR and to one of the fixed ends as per below and connected a variable end to one of the holes

like this:

View attachment 177361

Any idea which pin should i solder the potentiometer to?

 

should not matter... one goes to pot the other back into one of the holes where you removed the LDR... why are you posting info for the comparator? If that's on there... which makes sense... leave it alone. Just use the holes where you removed the original LDR.

 

should not matter... one goes to pot the other back into one of the holes where you removed the LDR... why are you posting info for the comparator? If that's on there... which makes sense... leave it alone. Just use the holes where you removed the original LDR.

Ok. Will try it out. Thanks ya.

 

Why do people buy such cheap junk? it has no description and no specifications.
Is it supposed to turn on a light only when it is dark and if there is any kind of sound?

 

* shrug... i can't read Chinese... but come to think of it I wouldn't trust this on mains voltage!

 

You get what you pay for. The cheap junk is not certified to be safe.
Since AliExpress cannot read English numbers they say that you get 10 of the modules for only $1.69US.

 

well no wonder people buy them... they are $0.13 each... no clue how they do that...

I was shopping for a chip the other day ... chips are about $1... PCB module with chip and regulator and some other stuff $1.23.

 

Hello,

no clue how they do that...

Working 9 to 9 for 6 days on cheap labour.
The parts in mass production.

They also seem not to care about safety.
The circuit contains a mains powered circuit, wic the TOS does not allow.

Bertus