I need your help...Relay (?) question...is this possible?

[ILoveC4]

Okay, so I have recently added my doorbell into my project, so that I can have actions trigger based on the doorbell ringing. This is great, and I love it...it works flawlessly. There is one bit of functionality that I just realized would be nice, and I am wondering if it is possible.

Here is how my doorbell is currently wired:

What I want to do is set it up so I can control whether the doorbell actually rings or not.

Now, I know that I can just eliminate the actual bell part of doorbell and have the alert be an announcement or something, but ideally I would keep the doorbell in the mix. What I was thinking I might be able to do is connect a relay inline somewhere that can stop the "signal" from going to the actual doorbell. What I would like to do for example is say that when the house is in "naptime" mode and someone rings the doorbell, the actual bell never goes off, it just sends a text message to my wife or something along those lines.

My doorbell is loud, and wakes up my kids.

Is this possible guys? If so, what do I need to do and where would I connect what I need to connect (a relay?)?

THANKS IN ADVANCE!

EDIT: Fix image...

[henniae]

You might be able to use a second set of relays. These relays would be connected to the doorbell buttons. The contacts of those relays would be hooked to a second transformer. When the doorbell button was pushed it would activate the relay and the Elk doorbell detector. When the contacts on the relay closed it would make the doorbell ring. If the second transformer had no power the bell would not ring. Control the second transformer with a C4 switch. In theory this should work. I only show one relay for the back door. A second relay would be needed for the front door. Sorry about the crude drawing.

[ILoveC4]

The "crude drawing" is fine, I appreciate the insight. I am not very familiar with all the things that can be done with relays, etc... I am still learning.

I would like to not involve a C4 switch if at all possible, I am trying to not add any real expense to this simple project.

I should also note that I only have one doorbell hooked up. I hate doorbells, and was half tempted to not even put one at the front door.

I was hoping I would be able to somehow use a relay on the back of the controller, and have programming open or close that relay, which would allow the signal to move forward to the bell based on the state of the relay. Is that possible?

[bhadams]

this may just work.

You can buy these relays just about anywhere (radioshack, etc), though i usually get them from standard supply on main and 34th, SLC. One will cover both front and back doors.

The idea is that in one relay state, the circuit will go through the bell. In the other relay state, the circuit will go through a resistor instead. I haven't calculated the value of the resistor. I was kind of hoping there was some electricians handy that could verify this design and make the appropriate suggestion.

It should work.

[neildilgee]

I always believe to work with what ever you have. And you already have a lot. So I'm not sure if I'm talk sense but you already have a C4 contact in your circuit. I'm pretty sure there's an option where you can invert that contact. I think you should start looking there.

[ILoveC4]

this may just work.

You can buy these relays just about anywhere (radioshack, etc), though i usually get them from standard supply on main and 34th, SLC. One will cover both front and back doors.

The idea is that in one relay state, the circuit will go through the bell. In the other relay state, the circuit will go through a resistor instead. I haven't calculated the value of the resistor. I was kind of hoping there was some electricians handy that could verify this design and make the appropriate suggestion.

It should work.

Call me a simpleton, but I need you to elaborate a little bit more.

If I understand this correctly I would use a relay purchased at Standard Supply as well as a relay on one of my C4 controllers? And then I could have different things toggle the C4 relay, and depending on whether or not the C4 relay was opened it would either ring or not ring the bell, is that correct?

Sorry, just trying to get my head around all this.

If you provide the solution, being that you're local, I'll buy you a sandwich =)

[bhadams]

Thats the idea.

You program the state of the C4 relay. In one case the bell rings. In the other case, the current goes through the resister instead and no ringing bell. You need a resister to provide a current change that the doorbell detector can see.

When you pair a C4 relay with the dedicated 12vdc output on the back of the controller you create a switchable 12volt trigger. Pair this with the 12volt coil relay and now you can switch dc, ac, line voltage, anything. Usually you see this configuration to control a motorized theater screen, but the idea is the same. I suggested the dpdt version (double pull double throw) because one could cover your whole setup and only use one c4 relay.

Making more sense or less?

[ILoveC4]

Thats the idea.

You program the state of the C4 relay. In one case the bell rings. In the other case, the current goes through the resister instead and no ringing bell. You need a resister to provide a current change that the doorbell detector can see.

When you pair a C4 relay with the dedicated 12vdc output on the back of the controller you create a switchable 12volt trigger. Pair this with the 12volt coil relay and now you can switch dc, ac, line voltage, anything. Usually you see this configuration to control a motorized theater screen, but the idea is the same. I suggested the dpdt version (double pull double throw) because one could cover your whole setup and only use one c4 relay.

Making more sense or less?

Makes more sense, but it still a little over my head being that I have never really worked with circuitry or relays. If you get a chance and you are willing to help, shoot me an email and we can IM or something. That way we can keep the thread clean, but I can post the result for everybody after you help me get it working.

Thanks bhadams

[ILoveC4]

How would it look with a relay controlling a relay? This is starting to make sense, but still a little confusing.

Thanks again for your help...I am excited to have hopefully found a solution.

[bhadams]

here's how you make a c4 relay act as a 12 volt trigger for starters

[ILoveC4]

Yeah, I get that part.

I'll go see them tomorrow and buy a DPDT coil relay (correct?). How many resistors do I need? Also, I assume these come in different sizes?

[bhadams]

here's the relay I'm refering too:

http://www.radioshack.com/product/index.jsp?productId=2049722

When you provide the relay with 12 volts, it switches. You just wire the 12v to the Com and NC and the Ground from the HC300 to the 12 volt coil on the relay and that's it.

Is anyone else using these? I use them on motorized screens all the time.

[bhadams]

The resistor is the part I need some input on. There are many different ones. We just want one that has a similar resistance value and wattage level as the chime. I'm hoping for an electrician to save me here.

[ILoveC4]

So I wouldn't neeed a resistor like was mentioned earlier?

It is starting to make sense now.

I can have "naptime mode" toggle the C4 relay basically on or off, because it is acting as a 12volt trigger. When the C4 relay is open, it will provide power to the relay from "The Shack". When the relay from "The Shack" has power provided to it from the C4 relay it will allow the physical doorbell to ring. When the relay from "The Shack" has no power (the C4 relay is closed) it will not allow the physical doorbell to ring. Whether the C4 relay is open or closed, the Elk930 will be able to still sense when the doorbell is pressed and toggle my C4 contact.

Is that all correct? Thanks for the detailed help...I really appreciate it.

[ILoveC4]

My question about the resistor was posed before I saw your post stating I would still need it.

Sorry.

[bhadams]

Your explaination is correct. And yes, whether the c4 relay is open or closed, the elk will be able to sense a button press. The resister in the circuit is essentially a dummy bell. We just need to determine which one. If we don't hear any good suggestions, I'll measure my bell and post a suggestion tomorrow.

I know its just a doorbell, but please be careful and don't kill yourself Dan. You're welcome to email me.

[ILoveC4]

Thanks buddy. I'll watch for a resistor suggestion, and then hopefully pick this stuff up tomorrow.

If I have any questions or hangups I'll shoot you an email. I do want to live to at least see Christmas, so I'll be cautious. Thanks again.

[wingzz]

After looking around it looks like doorbell chimes vary quite a bit in the resistance, I would start out with a 470 Ohm resister and see if that does the trick, it should be enough, be sure to get a 1/2 watt one just to be safe as I don't know the current output from your transformer

[ILoveC4]

Should I meter the output on the transformer?

I have a meter, you just may need to tell me which setting to use (there's about 50). I don't understand Watts and ohms and all that very well.

Thanks.

[wingzz]

Should I meter the output on the transformer?

I have a meter, you just may need to tell me which setting to use (there's about 50). I don't understand Watts and ohms and all that very well.

Thanks.

Use the ohm setting (you may have to adjust the range if it isn't autoranging) and measure the door bell coil, that would be the transformer input and the back and front door inputs, see what that measures, (is your meter digital?) in ohms, one lead on the transformer input and the other to the front door input, what does that measure? now from the transformer and the back door input, what does that measure, they should be about the same

post back what you find

[ILoveC4]

I only have one doorbell, I hate doorbells so I didn't put one on the service door or the back door. People that come to the service door know how to get in anyways.

I'll measure it this morning and let you know.

Yes, the meter is digital.

Thanks everybody for your help thus far.

[wingzz]

I only have one doorbell, I hate doorbells so I didn't put one on the service door or the back door. People that come to the service door know how to get in anyways.

I'll measure it this morning and let you know.

Yes, the meter is digital.

Thanks everybody for your help thus far.

ok if it's digital it should autorange, it not and it shows either all dashes or the display flashes them you'll have to move up to the next ohm range to get a reading

[ILoveC4]

Ohms is the one that looks like a horseshoe, right?

When I put the meter in that section, on the number 200 (lowest number) the display reads 7.0 to 7.6.

If I select a higher number the meter reads zero.

[henniae]

Ohms is the little horseshoe (majuscule Greek letter Omega). Look, I learned a new word Ma.

When you put your meter on the 200 setting you are telling it to measure in a small range (i.e. 0 to 200). When you put it on a higher range selector you of course telling it to measure higher values. In the 200 range setting you are measuring about 7 Ohms.

[bhadams]

This is my recommendation:

http://www.radioshack.com/product/index.jsp?productId=2062291

I measured my bell. It is around 8.5 ohms, the transformer has 20.5 VAC, and it draws about .90 Amps when the button is pushed. Now I'm no electrician (I was hoping for one by now), so I'm not that good with AC power calculations, but we are dealing with somewhere around 10 watts or less. Using this 10 watt resistor should be fine and not burn up.

I'd try this.