I have a really nice RAB motion sensor/halogen flood light set up, and
I want to run a wire from the output side (which turns on the floods)
into my house so that it notifies me with a small light bulb in my
That part is fine, but I want to have a momentary buzzer or chime come
on when it is first tripped. How can I do this?
Why not just purchase something like this
Or this http://www.x10.com/products/sc546a_sp_tm_ps42.html
Or this http://www.gadgetshack.com/reporter.html
You get the idea. There are many other types of sensors you can use without
goiong through the hassle of reqiring the floodlights.
I have something just like that (Dakota Alert) which is great. I just
want to also do the flood lights. (Its a hobby thing)
I was going to suggest to you, Dakota Alert. Their unit has a set of
contacts in the receiver, that are time adjustable and can be connected to a
piezo buzzer. You can build one yourself, but it's a tad complex. You need
an adjustable time relay, that's adjustable to fractions of seconds. It must
have a 120 volt coil and a normally open switch contact. You need a signal
device,( buzzer), and a power supply of the same voltage. Wire the relay so
it closes switch circuit for fraction of a second whenever lights comes on
sending low voltage to buzzer through switch circuit
That would work if he wanted a buzzer to ring the entire time the light is
on - probably 2-3 minutes minimum if it is like most motion lights.
He's probably going to need a relay of some sort that will trip when the 110
current is detected and cause a momentary trip-switch to toggle to ring the
buzzer or bell. The relay will have to remain tripped until the 110 is
off (when the motion light goes out), recycling the trip-switch for the next
time the motion light comes on.
Any of these will operate at 50/60 Hz and sense the current by just
looping the insulated hot lead through the coil one time. When
current flows in the house wire a small voltage will be induced in the
coil and be enough to trigger the Elk relay. These current sensing
coils typically cost around 1 to 4 dollars retail:
I use this same setup to turn on a humidifier whenever the furnace fan
turns on (with no physical connection being made to the fan circuit
other than the current sensor). Similar priciple as an AC clamp amp-
There are more manufacturers than this place try Global Spec to find a
Wire a slow-blow fuse into the line to the buzzer. With enough trial
and error you'll find one that lasts only as long as you want the
buzzer to sound before it blows.
Hang on, I know what you're going to say next: "I want something that
will work more than once."
All you need to build now is a "Automatic Fuse Replacement" mechanism
that will eject the old fuse from its holder and insert a new one.
Wait - I got a better idea: - seriously, this might work:
Get a mercury switch and make a mount attached to a 110 motor that
only moves a fraction of a rotation when energized. When the light
comes on, the mercury switch will close the circuit to the buzzer/bell
but the motor will also come on and tilt the switch, turning off the
buzzer. The motor will stay energized (and the switch will remain
open) until the light goes out at which time it will return to it's
original position and arm the mercury switch.
For some reason this reminds me of the 3-strike relay we had in a 30KV
transmitter power supply I used to work on. If the xmtr shorted to
ground (which it had a tendency to do) it would trip a motorized
breaker and the 3-strike relay would set its contacts to the one-
strike position. The breaker motor would reset the main breaker and if
nothing happened within 30 secs, a small motor would reset the relay.
If the xmtr arced again within 30 secs, the contacts would move to a
second-strike position and let the big motor would reset the main
breaker one more time. If there were no more arcs within the original
30 seconds, the relay would reset itself to the original position and
hum merrily along. However, if 3 arcs happened within 30 seconds, the
relay contacts would go into the third-strike position and kill power
to the breaker motor so it couldn't reset the breaker. At that point
the xmtr was dead until we visited the machine and figured why it was
It was a pretty neat electro-mechanical device that prevented down-
time due to the occasional arc, but prevented major damage if there
was a serious problem with the xmtr.
Install a doorbell transformer which will be powered by the 110
current from the motion sensor when it activates. No doorbell button
is used. Low voltage to light, bell or whistle in the house.
Transformer can mount close to sensor.
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