[Stratmando]

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.

[Woodbob]

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.

[Stratmando]

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.

[KISS]

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.

[Woodbob]

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

[KISS]

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.

[Woodbob]

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

[Stratmando]

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.

[KISS]

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

[KISS]

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.

[Woodbob]

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

[KISS]

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

[Woodbob]

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

[Stratmando]

You may not even need the resistor?

[KISS]

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.

[Woodbob]

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

[Stratmando]

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.

[KISS]

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

[Woodbob]

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?

[KISS]

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.