Schematics question

Are you using a controller?

I'm assuming that you are using a power supply, a photo sensor, and a bell.

The power supply will have a positive (+) and a negative (-) output.

The bell, as you stated, has a (+) and a (-).

The photo sensor should have a (+) and a (-) , COM, NC, and NO.

Wire from the power supply (-) to the photo sensor (-), and to the bell (-).

Wire from the power supply (+) to the photo sensor (+), and the photo sensor (COM).

Wire from the photo sensor (NO) to the bell (+).

Hi, I am reading instrutions on hooking up an Intellibeam IB-250s intruder alarm system.. It sends a beam from transmitter to reciever and if broken sets alarm off. I see in the diagram it has 3 wires going from the reciever to the alarm.. It says: Output Alarm, then three lines with one appearing to be a switch from the middle line going to the third line(it is touching the third line)..each line/wire is labelled: N.O. COM and N.C. I have a simple bell alarm or whistle alarm which only have two wires coming off. What is the third wire for? Thanks req

COM is common, NO is Normally Open, and NC is Normally Closed, these are the contacts of the relay that controls the output. The connection between COM and NO closes when activated, while the that between COM and NC opens when activated.

Thanks for the response. how do I connect those three wires to the two wire bell, if that is the way to do it.. the alarm has positve and negative wires only. Layman here req

Those contacts are just a switch, it sounds like you need a separate power source for your alarm. You would wire the N.O. and COM terminals just as you'd wire a switch in series with power to the alarm. When the relay is triggered, the contacts close and it completes the circuit.

I really apprecite you taking the time out to answer my query...so where do the three lines go if I do get a separate source...the question is where do the three lines go thanks req

Do you have a DC power supply and some wire for the photo sensor?

How about a Continuity tester (Ohm meter)?

Stand alone req

Would doohickey and thingamajig suffice?

Depends on whether you want the alarm to sound when the relay closes or the relay opens. Like I said, it's a switch, one input and two mutually exclusive outputs. Imagine a valve that can direct water from one input (COM) to either of two outputs. Hook it up and see what happens, if the alarm sounds when you want it quiet and is quiet when you want it to sound, change to the other contact.

The relays are low voltage, low current and intended to be connected to an alarm panel.

Usually such devices are not self powered, and a gander at the HWell website states an input power, which, to me, means that the device is not self powered.

You need to find out the current draw of your bell/ringer and get a power supply that will power it and the photo sensor. The photo sensor uses 50 mA. That is a negligible quantity. Look at the name plate of the bell/ringer and find out what the current draw is, multiply that number by 2, and find a power supply that will provide the current and the proper voltage while making sure that the available current is *more* than the sum of the sensor and bell together. Getting more power than you need is not a bad thing.

This leads to the next thought in this process. How handy are you? There are different types of power supplies, and I'd recommend getting a cheap wall-wart type for this project as long as you know how to use the meter and how to determine the polarity of the power supply. If there is any thought of expanding this system, then I'd ask you to go and look for a quality power supply. Of course, this leads to more complications...such as have you ever spliced into a 120vac cord and do you know how to properly connect such a cord to a device?

I want the alarm to sound when someone breaks the beam. layman here. req

Around here?

The opposite. Normal =3D=3D *not* energized

"Continuity tester" "DC power supply" "mutually exclusive outputs" "Ohm"

layman whoosh, ye need to dumb down folks!

Not sure if that's sarcasm or not, but this *is* an engineering group. There are plenty of other forums and websites for more basic information. You wouldn't call up a master carpenter to ask how to nail two boards together and then ask what a hammer is.

The device itself provides the power for the alarm I think. Yes I have a continuity tester I gave the name of the device req

Not THAT much of a layman :-) req

I'm not asking what a *hammer* is.. my question is not that remedial thanks req