K
Kevin Walton
Hi
I have purchased a Lost Model Alarm with a circuit that looks like
this:
http://mach.unseen.org/~kevin/electronics/lma/lma1.gif
IC1 is a PIC 12C508A, TR1 is a transistor marked 2N02, C1 is I assume
a supply decoupling capacitor.
The PIC is powered from the Remote Control Reciever battery.
switiching on the alarm if no signel is recieved at connection point
S.
This circuit has a design problem, even though it has it's own
integral battery if the reciever battery is not connected then the
alarm wont sound. I would like to solve this by powering the circuit
from the internal 12v battery. So, whenever a singlan is not present
at S the alarm will sound.
I atempted this like so:
http://mach.unseen.org/~kevin/electronics/lma/lma2.gif
IC2 is a 78L05, 5V regulator, in theory taking 12V and producing 5v.
However this circuit now just alway provides a small voltage to the
alarm continuously and the presence of signal at the input makes no
difference.
I am obviously missing a fatal problem, can someone point it out and
possibly explain a way around the problem for me please?
Thanks
Kev
kevin at unseen dot org
I have purchased a Lost Model Alarm with a circuit that looks like
this:
http://mach.unseen.org/~kevin/electronics/lma/lma1.gif
IC1 is a PIC 12C508A, TR1 is a transistor marked 2N02, C1 is I assume
a supply decoupling capacitor.
The PIC is powered from the Remote Control Reciever battery.
switiching on the alarm if no signel is recieved at connection point
S.
This circuit has a design problem, even though it has it's own
integral battery if the reciever battery is not connected then the
alarm wont sound. I would like to solve this by powering the circuit
from the internal 12v battery. So, whenever a singlan is not present
at S the alarm will sound.
I atempted this like so:
http://mach.unseen.org/~kevin/electronics/lma/lma2.gif
IC2 is a 78L05, 5V regulator, in theory taking 12V and producing 5v.
However this circuit now just alway provides a small voltage to the
alarm continuously and the presence of signal at the input makes no
difference.
I am obviously missing a fatal problem, can someone point it out and
possibly explain a way around the problem for me please?
Thanks
Kev
kevin at unseen dot org