Good Job.
Measure the voltage across each of the diodes.
Same diodes should read the same, Don't know how much Overvoltage will knock out the led's.

Hi,

Thank you. I'm not sure how long the one LED will last because of the voltage. I was thinking of adding another same circuit with another LED in reverse to get the other half of the AC cycle and hope that the added circuit will reduce the voltage a little on the LED's.
Worth a try.

Not sure if they have higher voltage LED's
I'll take a look at the link KISS sent me.
I do have an electronic outlet not too far from me that I use.

Thanks again.

If the voltage is high at Led, Increasing resistor should fix.
Each led will block each others half cycle. They have to be inline(anode of 1 to cathode of the other). They do make bi colored Leds, which when reversing polarity, it lights the other color(red or green), they also make Tri-Colored Led's red with diode 1 direction, green is with the diode reversed, yellow when AC is present(no diode).
You still only need 2 conductors to doorbell switch.

Here is a 24 VAC relay data sheet: http://relays.tycoelectronics.com/datasheets/KHA_DS.pdf

Note that the coil resistance is 160 ohms.

I'm not addressing the easiest, best, cheapest etc. just a "how to".

24 VAC is standard in the AC world, but it's possible that many other voltages can work. You can even get a 24 VAC wall transformer or a transformer that mounts in a 4 x 4 outlet box.
Sometimes these transformers are designed as "energy limiting" so that the do not require fusing. A shoort will not damage them. So 24 VAC is a common voltage and parts are available for that voltage.

Using DC voltages can meke things more expensive because of contact protection. 24 DC is used in industries because of the ability to back up with simple 12 V batteries in series.

That out of the way.

You will note that you have two wires going over the wall and the "meat" of your doorbell is accessible.

If you cut the wires over the ceiling, this is where the "new circuit" splices in place.

The right pair going to the switch goes to a 24 VAC transformer and the relay coil wired in series. The value of R get's adjusted. 1K is a good place to start.

With just that connected, when you press the button the relay changes state. When the relay is off 24 VAC is supplied through the coil resistance of 160 ohms, the diode, the xtra resstance, the LED and the LED should light. Relays picked correctly, will not have enough current ot "pull in" when the LED is on.

Shorting out the extra resistance with the button will "pull in" the relay".

Pick two terminals of the relay that are open when the pushbutton is off and closed when on and connect it to the left side where your circuit was cut. This is like a switch and therefore the chime rings.

The same system can be extrapolated to work on your garage door.

Hi again,

Just back from my doctors - Lower back pain.. I could be resting for a few days!

Thanks for your help Stratmando and Kiss...

I'll be experminting with this and looking at your diagram, will advise.

By the way - just checked the button lite and bell - all still OK - for now

Thanks

Hope you feel better.

Just to re-iterate again:

You'd be making a simple circuit to close a relay when a push button is pressed. 24 VAC relays are common and 16 VAC ones are not likely to exist. The light across the push button is similar to a "bown fuse indicator". Neon lamps with 100K or so resistors have been used for 120 VAC circuits for a long time.
The relay more close resembles what a bell might look like, a low resistance wire.

So, you'd be replacing the button loop with one of a different voltage (namely 24 VAC).

The doorbell or garage door opener will see an actual switch just like it always did. No new wires are necessary.

Some ways to proceed:
A socketed relay mounted in a case and a 24 VAC wall-wart.

A socketed relay, a 24 VAC xformer, fuse, LED pilot lamp mounted in a case is another. Use either a plug in connector or a couple of terminal strips.

Can also put a 24 CAV xfomer mounted on a 4 x 4 plate (common in AC systems), put a relay in another junction box.

The Cadillac (may be another term now) is of course a NEMA enclosure, DIN rail, DIN rail transformer, DIN rail mounted relay with indicator and check button.

Still a DIN or screw terminal base for a relay would be nice.

All sorts of options.

A "check button" is available with some industrial relays. It allows activation with a momentary mechanical button.

An "indicator light" is just that, an indicator wired in the relay housing.

Again, there are also special purpose relays that can have an AC/DC coil combination. Rare, but useful, but not likely for this application.

Hi,

Thanks aagin for the help.. I'am feeling better. Seems when you get near a doctor everything clears up, just like a car going to a mechanic.

For now I have the new circuit on the project board and remounted on the push button.

One LED - One 10 Ohm resistor and one diode. I did stop back to Radio Shack and
Bought a couple of Green 20ma LED's, made no difference needed 10 ohms.

I'am using one LED now and all working.

I'am still looking at the diagram for the 24VAC system.

Thanks again

I like simple, you have a good solution, if it burns out, slowly increase the resistance.
The bi color led(red and green) can be easily switched from green to red, and back by reversing the diode. If you want to add a DPDT switch with the diode, you can select by the flip of a switch.
It did give me a good Idea to use with the alarm panel, the color of the door bell light will indicate, alarm condition(armed, dissarmed, alarm conditions). This just requires a dpdt relay in alarm panel.

Do me a quick favor and measure the resistance with your ohmmeter.

I'm wondering if your reading the color code of a 5 band resistor.

black brown brown black = 1000 ohms

and

black brown red is 1K when 3 bands

Take a look here at the relays and then click on the socket.

Search Results

This would be a typical way to mount an industrial relay. The socket mounts on a DIN rail or via screws. Some of the relays have the indicator and check buttons. Look at the DPDT ones for 24 VAC.

DIN rail is like an erector set for process control stuff. You can nearly plop anything electrical on it. Power supplies, relays, circuit cards, terminals, conectors etc. and re-use them. Everything is wired with screw terminals.

Hi,

Sorry but I bought packs of 5 each resistors and even if I couldn't read the color
Code it was stamped on the packages..

Bad-Boys-Rape-Our-Young-Girls-But-Violet-gives-willingly

Do you recall that sentence??

I was an electronics Tech. while in the Army.. I have a 10 Ohm resistor in place..

Thanks

OK, sorry. 10 ohms just doesn't seem right, but I/we don't have the schematic of the bell.

FYI: Here is a DIN rail mount transformer (not in US):

Legrand | Transformers | Transformers | Din-Rail, Panel, Wall Mounting Transformers | 12 and 24 Vac Din-Rail

Hi,

Thanks for the link.. Perhaps there's a high resistance in the input circuit of the electronic Bell.

I did write to the bell makers concerning a lighted push button but no response as yet.

Thank you

You may not even need the resistor?

You can actually measure indirectly what the input impedance is of the bell by getting an "appropriate" variable resistor. Put the resistor at it's highest value and adjust so that the voltage is half of the transformer voltage. Take the pot out of circuit an measure R. That's the internal R of the chime.

Hi,

Tried the 10 ohm reisitor, diode and a 20MA LED.. That lasted about 7 house and the LED blew out. I now have a 10 ohm resistor - diode and a 70MA Led in place and testing again.

I also added a 20ma LED and a 1K resistor across my garage push button and am testing this as well.

The garage button has approx 20 VDC - no need for the diode.

Will advise

We used the Bad boys as well for the resistor color code, even knew Women Tech's who used the same saying? Funny hearing them say it. As you try different resistances, measure voltage across LED. Too high, increase resistance.

I eventually used "Black" for "Bad" because it was easy to confuse black with brown. I also learned it as "Virginia" rather than "Violet".

Hi,

My test of the completed LED w/10 - Ohms worked fine for about 8 hours then all shut down. No Led and no chime. Took an off/on of the xfrmer circuit breaker to restore. Then all back on.

Seems that the Bell electronics shuts everything down with the LED setup in place.

Here's what I think I know so far.

The system works fine with only a diode across the button, all notes are played.

The system MUST have a diode across the button to complete all 8 notes of the chime.

Putting the LED system across the button lites and works for about 7 hours.

Putting the relay in series will add 160 Ohms of reistance and I think it will stop the chimes from playing all 8 notes. I couldn't even add 10more ohms to the LED system

If I used the 24 volt relay on my 16 Volt system I don't think the 16 volts will energize
The relay. Need 85% of the required voltage

Even if I found a way to energize the relay then I must have a diode across the button to complete the chimes.

I was thiking about a separate 24 VAC Xfrmer to energize the relay and using the contacts to switch the LED and diode in place across the switch and feed the Bell Electronics.

Any ideas?

Quote:

---

Originally Posted by Woodbob

I was thiking about a seperate 24 VAC Xfrmer to energize the relay and using the contacts to switch the LED and diode in place across the switch and feed the Bell Electronics.

---

This is a little confusing, but it was essentially what I said.

Your new circuit consists o a transformer, the switch/led/resistor/diode) combination and a relay with a 24 VAC coil.

A set of normally open contacts interface with the doorbell to the wires leftover.

No new wires need to be pulled.

DC could be used as well. Remove the diode in the bell and put it across the relay reverse biased, to absorb coil collapse spikes.

Check All Electronics | Electronic and Electro-Mechanical Parts and Supplies at Discount Prices for some surplus parts.

Hi,

Back to square one! As I reported I decided to sleep on things for awhile and installed the button the way the manufacture requested. Just the diode across the button.

I checked the bell chime and all worked fine overnight. Today it's off, no chime.

Had to switch the circuit breaker on/off to reset.

Now of course I don't know if it was the chime all along! I'm leaving everything as is over night and if it's out again I'll exchange it at Lowe's.

My only thought is was it really defective out of the box or did the LED - Diode - Resistor cause a problem within the chime??

Won't know till tomorrow or perhaps the next day. If I exchange it I'll test it for a full day.

I purchased a resistor substitution box today, thought that might be better then swapping resistors by hand while building a project!

Thanks again

When you say a diode across, do you mean diode or led? I know the led is a diode. With just a diode you will be shunting during the half cycle, loading transformer down.
A diode, led and resistor should work, be sure when all is in place, the LED see the required voltage.

I did some online searching because the "diode" thing was interesting. What I learned was that without the diode across the button, the chime will supposedly only ring for as long as your holding the button. It is only required on the front doorbel and not the rear.

Based on that information, I do think your only recourse is to use a second 24 VAC circuit and to put the diode across the contacts of the new relay.

Hi,

You are correct about the diode. Hold the button and all works fine. Diode needed.

My question and problem is that even with a relay I'm having difficulty putting the diode across the button when the button is released via a relay. You will always have the led diode and resistor across the button. Adding the new relay the added coil resistance will knock out the chimes if put in series.

You can use the relay to add the diode but when you de-energize the relay there goes the diode. When used the diode is circumventing the Led/Diode - I think??

Can you draw a sketch, please

I could add a separate 24AC Xfrmer and use the button to energize the 24VAC relay and control the 16VAC to the chime through the 24 VAC relay.

My supply and the bell chime are only 16 VAC.. I don't think that's enough to energize the relay.

I still like my Double connector switch.. two SPST (DPST) but I'd need to add some witing to the switch.. Going to dust off my hammer and drill for the walls, just in case.

Thanks

Hi,

Would you know if they make "Time delay" relays that energize w/o delay but de-energize with a set delay..

I know they have time delay relays but I think it energizing??

If there is then perhaps you could delay the circuit when you release the button and keep the chimes going..

Just a thought

Thanks

I think I have a way to make this a lot simpler.

Pick up a 5V relay 275-240 at radio shack and a small full wave bridge rectifier. The relay has a coil resistance of about 55 ohms.

For now get a 20 mA LED and a 50 ohm resistor, probably 1/2 watt resistor of two 100 ohm 1/4 watts in parallel.

You'll also need a doorbell diode , but let's leave this out for now.

Take the bridge and connect it to the 16 VAC transformer

Connect the doorbell switch (S1) in series with the relay and the output of the bridge rectifier. The DC voltage should be about 7V from the bridge. Don't bother using a capacitor for filtering.

Test. The relay should engage when you push the button. So far, so good.

Now add a diode across the relay coil reverse biased. Plus of diode to (-) of relay. (+) of diode to the negative supply. This is transient suppression.

Now take the 50 ohm resistor and the LED and place across the doorbell button.

Test.

Light should go out when the button is depressed.

You should be able to do this on your bench, if I remember right.

No chime or final connections at this point.

If all works out, you can upgrade the LED and reduce the 50 ohm resistor and test.

Hi,

I'll p/u the parts soon.. Here's a schematic I drew... What do you think?

I realize it has a relay, another transformer and an extra diode.

Will this do it? As you can see the extra diode runs through the NC contacts of the relay putting it across the switch when released.

Thanks

That's essentially the original design I was contemplating, but I didn't know about the diode across the button thing.

It's correct EXCEPT, the diode has to go across the (C) and (NO) contacts in the correct order.

The 5V DC design looses the transformer.

Hi,

If the diode is moved as you suggest, wouldn't that take it out of the circuit when the button is released, and the chime would stop?

Pushing the button gets it going, and after the relay de-energizes the diode on the NC connects it across the switch. The LED/Diode is only to lite the switch.

Am I missing something.. I toyed with it's placement and did start with the NO side.

Thanks

Hi,

Very strange. The bell is still working

I think it will work the way you've drawn it, but it's now how the mfr intended. They want the diode across the switch and then the switch shorts it out when pressed. Your circuit doesn't operate that way.

Part II

There is a non-destructive phenomenon with CMOS chips where charge gets moved inside the IC and alters the behavior. Eventually the charge leaks out and the device works again. I had a co-worker who slid a bike with a bike speedometer across the car rug. System broke. Took battery out. Shorted battery terminals. System fixed. I have other stories too.

Hi,

Like I said, I toyed with it's placement. I do know that when I had it across the switch with the LED, and the resistance was too high it didn't work, as if the diode wasn't there.

Actually, while writing this I was looking at the drawing and I believe you are correct.

Putting the diode on between the C and NO puts the diode into the "Front" chime as they designed.

Pushing the button energizes the relay connecting the C to the NO, shorting the diode, releasing again puts the diode back in series with the chime.

I hope!

Hope my bell still works in the AM - just tried it and it's still working.

Thanks

Hi,

Here's what might be the completed schematic w/16Volts. A little down hill drawing but I know electronics can go up hill!

I haven't tried the bell chime yet - too early here.

Thanks

Hi,

I believe I have an error in my bridge set up..

Back soon.

This is basically what I was thinking of. If I remember my formulas right you'll get about 7 VDC or so. As long as the voltage can cause the relay to pull in you should be fine, otherwise the overvoltage is only going to last for the length of the press.

Hi,

Good news first: The chime works as the mfg suggested - all OK with only the diode in place, no need to exchange.

I bench tested the bridge and got 16VDC out of the Bridge. Is this the over voltage you spoke about? Can't it be reduced to the 7VDC?

I believe I made a wiring error after looking at your sketch.. I put my resistor substitution box together today. I wanted to get something working!

My previous sketch had the bridge wired incorrectly, which I saw before I actually wired it.

I'll give your sketch a try tomorrow.

Thanks for the sketch and help

Hi,

I'll re-measure the voltage after I rewire it correctly.

Thanks

When you say diode, I take you mean Led, is it a 7 volt Led?
The resistor you add should bring the voltage down to LED Voltage.
Since you have 16 Volts DC, To find the resistor, divide the LED current into 16 minus the LED voltage.

I would try the full wave bridge at the door bell, Parallel the ac in on bridge with door bell contacts, then take the DC out, through resistor, then to LED, other lead goes to bridge Minus.
If the full wave bridge is too big to fit in the hole, make a bridge out of 4 diodes, then you can assemble so the hole needs to be big enough for 2 diodes side by side, inline with the other 2 diodes side by side.

Hi,

No, it isn't the LED it's a chime diode. The system is working as it came out of the box.

If you recall I had the normal system stop working after 7 -8 hours that's why I'm testing it as the manfg. Suggested, in case I had a bad chime.

The circuit I'm testing ( Relay - LED - Bridge ) is on the bench.

Thanks again. I'll be at it tomorrow, I think