buzzer only beep once


Posted on Feb 7, 2014

basically i have what is known as a bite alarm (for fishing). normally bite alarms beep as the fishing line passes over a wheel which usually has notches in it to allow some sort of optical switching making it go beep-beep-beep until the wheel stops. however i have been given some particularly cheap alarms which quite often get stuck with the buzz


buzzer only beep once
Click here to download the full size of the above Circuit.

er constantly on and i have to physically move the wheel to silence the buzzer. I have discovered that this alarm uses a reed switch with magnets on the wheel, so if the magnet gets stuck next to the reed switch the buzzer sounds constantly. I have connected everything as it is on the diagram and with the added notes in your last post to no avail, the only difference being that i am using a bc548.




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