Want a motion sensor / flood to buzz indoors momentarily...

[dean]

Hi all,

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 living room.

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?

Thanks!

-Dean

[SBH]

Why not just purchase something like this

?

Or this

Or this You get the idea. There are many other types of sensors you can use without goiong through the hassle of reqiring the floodlights.

[DeanB]

I have something just like that (Dakota Alert) which is great. I just want to also do the flood lights. (Its a hobby thing)

[WW]

Check the voltage at the light bulb and replace with a buzzer of same voltage? WW

[Mark]

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.

[RBM]

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

[RickH]

This is the cheapest solution I know of ($29):

The Elk timer relays are pretty handy, just mount it inside a steel J box with some nylon standoffs and 6-32 machine screws and nuts.

but for the count-down off feature you described the above the ELK-960 above would be it, it even has a "pulse mode" to flash the inside light based on continuous current detection in another circuit, or just do a timed off of the inside bulb.

Other relays without the timer feature:

[DeanB]

Thanks - Would work if I had the lower voltage, but I'm stuck with

110V output from the motion sensor (don't particularly want to add a transformer).

[RickH]

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- meter.

There are more manufacturers than this place try Global Spec to find a web seller.

[DerbyDad03]

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 arcing.

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.

[DeanB]

That would seem to be ideal. Thanks for the response.

[Hustlin' Hank]

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.

[David Nebenzahl]

On 3/25/2009 11:15 PM Hustlin' Hank spake thus:

Like so many others, you missed the "momentary" part of the O.P.'s desired result.