alarm circuit issue

leonheard1

Jan 26, 2013
14
Joined
Jan 26, 2013
Messages
14
hello!!!

i made a alarm circuit with a fototransistor and ir led , when the door opens it turns ON and a siren HIGH sound activates and the only way to turn it off is manually…. anyway it works great!
but when the power supply ( a 3.5 v battery ) is On for about 7 hours, it automatically turns the alarm ON! and that’s bad.

my theory is that  when time goes it spends  current, so the 3.5 v battery doesn’t have the same amount of
current like 7 h before, so the “sensor” is like more or less sensitive and triggers the alarm….


how can I solve that problem? do I have to use some sort of HIGH PASS filter?

please help.

 
R

remonx6

Jan 1, 1970
0
yes Thanks Author I attach a Door alarm circuit diagram thanks

d.png

 
J

Jibby

Jan 1, 1970
0
Only way to redesign for driving the circuit to sleep mode while no signal is received to save battery power

 
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