Someone Electro
New Member
I got an LED bar dB meter and riped its chip out.It was an KA2281 LED bar driver chip.And its to the bredbord for some experementing.
So i asembald it on an bredbord as shown in the datashet ( **broken link removed** ) as i spoted from the datashet the biger the resistance betwen pin 1 and 2 or 16 and 15 the biger the gain so in the end an 1 Mohm resistor ended up in the bredbord.
Then i was conecting all sorts of stuf to it:a speaker ,piezo trnsducer... But wen i conected and secondary form an 220V to 6V transformer the bar has sudenly lit it self.Then o found that the elecrtomagnetic waves in generated in my monitor (in front of me so i cod se the datashet)ware being piked op by the coil.
Then i got the idea to use it as an in wall wire seker.So i thurned on the light and put the coil above the switch and herika it worked
But the problem is the first two leds keep lit proboly becose of radio waves being picked up by the wery sensetive preamp
I never wod of thogt that an LED bar driver chip wod make an alternating magnetic field detector (the cool thing is that it displays the strenth to)
So i asembald it on an bredbord as shown in the datashet ( **broken link removed** ) as i spoted from the datashet the biger the resistance betwen pin 1 and 2 or 16 and 15 the biger the gain so in the end an 1 Mohm resistor ended up in the bredbord.
Then i was conecting all sorts of stuf to it:a speaker ,piezo trnsducer... But wen i conected and secondary form an 220V to 6V transformer the bar has sudenly lit it self.Then o found that the elecrtomagnetic waves in generated in my monitor (in front of me so i cod se the datashet)ware being piked op by the coil.
Then i got the idea to use it as an in wall wire seker.So i thurned on the light and put the coil above the switch and herika it worked
But the problem is the first two leds keep lit proboly becose of radio waves being picked up by the wery sensetive preamp
I never wod of thogt that an LED bar driver chip wod make an alternating magnetic field detector (the cool thing is that it displays the strenth to)