Important Note:
This circuit should only be used with the
solenoid type chime doorbells, the electronic type that play tunes will not work here.
Notes:
The hardest part for this circuit was the
title. It is quite easy to miss the sound of a doorbell if you are
watching TV , this circuit gets
round the problem by providing a visual indication, i.e. a lamp. As an
alternative, a LED could also be
used. You could just parallel a lamp across the doorbell, but this would
mean extra drain from
the doorbell batteries or transformer. Using a series resistor R1 actually reduces
current flow , and if run from batteries, will give them a longer life. The value of R1 is chosen so that
about 0.6 to 0.7 volts is dropped across it, and the doorbell should
still ring. I used a combination of a 22
ohm resistor in parallel with a 50 ohm. The doorbell still rang and circuit operated correctly. I used to have
an electromechanical counter that registered each time when someone pressed the switch....in fact, I
remember a time when I had more "hits" at my doorbell then at my web site=:)
