Of course there is, we used to call them 'Intermediate' switches you can have any amount you wish.

This might be something I know about, but not by the right name. Examples - ?

ak

 

Perhaps understanding the need is key to finding a solution.

For that guy, maybe. But as I've said, I don't understand that poster's particular need. It triggered a memory.

ak

 

Is this a good time to bring up an impulse relay - ?

ak

 

This might be something I know about, but not by the right name. Examples - ?

Ordinary intermediate switches. inserted anywhere on the travelers. Increase number of intermediate sw as needed.

 

Yep. In my case it was worth the $60 to use the wireless switch rather than to tear up newly finished drywall to pull wire.

What powers the <gasp> electronics?

ak

 

We have several multiple way switches and some I some I flip sometimes by putting my arm around a corner where I cannot see the switch, so I have no visual indication of whether the switch needs to be flipped up or down. I don’t remember having to fumble around when doing that, do I went and tried one to see how I handled it. I reached for the switch with my index and middle fingers open like scissors. When I find the switch my fingers can tell which way it is and flip it and can do so either way since I have one finger below it and one finger above.

 

Wow, does that ever sound like a code violation.

I don't know one way or the other. I've wondered myself, but the house has been through several inspections, including when it was built and each time it has been sold and there's never been any mention. Two of the inspections were very thorough and pointed out pretty minor code violations, I don't know about the others.

 

As for 3 way switches - you're always going to have either both up or down and the light is on (or off) OR one switch is up and the other is down. Just works out that way. As for ascertaining the status of the light - I'm assuming this is a light that is remote and can not be observed from where the switches are. The only thing I can think of is having an indicator light indicating when there's current flowing through the switch. If the indicator light is on then the remote light is on.

The indicator lamp on a 3-way switch is normally lit when the light is off. This is because the common way it is implemented is that the switch shorts out the indicator in order to provide a low-resistance path for for the light. The indicator provides a high-resistance leakage path when the light is off that has enough current to light the indicator but not enough to light up the light itself.

 

That might be true in the States, but not necessarily so in other countries. Here in the UK, Up is normally Off.

By all means, decide on a preferred status for a specific state that is consistent with local custom. The issue is still the same -- a large fraction of electricians, builders, and installers do not grasp that a three- or four-way installation can even HAVE a preferred status for a specific state.

 

I had an idea about this in high school; wish I had patented it then. Something on another forum triggered the memory. Don't know if it is available commercially.

The topic is 3-way house light switches, and how the toggle position does not always reflect the On-ness of the lights,

Replace the toggle switch with a SPST pushbutton switch, and a toggle flipflop driving a TRIAC. That can be a stand-alone switch, or there can be as many remote switches as you want, all in parallel. Any one of them can toggle the flipflop from whatever state it is in to the other one. Cosmetically, the master switch with the electronics and TRIAC would look exactly the same as the remotes - a simple pushbutton dome in a standard wall box device.

The basic approach would lose its toggle status with every power blink. BUT, in an era of a SOT-26 uC for 44 cents in *ones*, the solution is one of them critters that stores the toggle state in flash.

ak

Hi,

In this day and age? Gee you can do almost anything your heart desires with a simple and common solution. Enter, the microcontroller.
That's for a custom roll your own, which is probably what I would do if i felt like messing with the project. You can use push button switches as you said, and just have an LED under each one that stays lit all the time or just when the main light is 'off'.

If you don't want to roll your own, then I might suggest the wireless switches and wireless bulb sockets. You can buy these online and they are not super expensive. With these you can program several switches to activate the same light socket, and maybe even more than one socket if you need more than one light to come on in a different place.
The only drawback here is i am not sure if they also contain some sort of LED indicator, maybe because the switches run on small batteries and they would drain down. That does not stop you from modifying them though to include a nano power microcontroller and an LED that only blinks once every 5 seconds or something and only stays on for a fraction of a second. When you do it that way you can get battery life in the years, like 2 years, without too much effort. The switch state would be easy to detect because you get one button for 'on' and one for 'off'. You just need to interface with those push switches with the uC IC in order to detect the on/off control initiated by the human operator.

I think it would be nicer to do the microcontroller version where you roll your own. That gives you a lot of flexibility not only for future functions (auto turn on/off when not home) but also for future add-ons. Might actually be fun to build too. You'd always have power also unless the power goes out during a storm, but most microcontrollers these days have built in flash memory so it's no problem to store the state, and you could implement your own trimming code to allow that flash to last longer than the time any of the other electronics would die out, by a factor of 20 i bet.

 

Is this a good time to bring up an impulse relay - ?

ak

For sure yes !

An 'impulse' or 'ratchet' relay changes state with a pulse input to its coil and reverts on the subsequent pulse.

In other words, it changes state on consecutive pulse inputs to its coil.

The application schematic is as follows:



The lamp is switched on with one push of either button and switched off on the subsequent push.

Here's an animation, courtesy Homofaciens.de, that gives an idea of how the impulse relay works.

Nandu.

 

What powers the <gasp> electronics?

ak

It's got a lithium coin cell.

 

Well, the should set off another round.

ak

 

Is this a good time to bring up an impulse relay - ?

ak

INDEED!!! The 24 volt impulse relay has been available for at least 60 years, and it allows any number of control points that always have the same on and off position. And they work quite well. That same scheme can also switch on lights in diverse locations at the same time.
The cost for the impulse relay is a bit more, but the main shortcoming was that way to many folks had no clue as to how they were to be connected, since the impulse relay had five wires. The clueless fools would get it wrong and never get them working right.

 

Sorry, Bill, but that was meant as a joke; just poking the bear.

The telephone rotary dial and automated telephone exchange date back to the 1890's. The stepper relay was an extension of a simple impulse relay. A family friend who had an amazing collection of bits and pieces gave me one back in the 60's. A perk of having Western electric's #1 plant in town was a working mini phone exchange exhibit in the local Science and Industry museum.

ak

 

The 24 volt impulse relays have one coil for "ON" and a second coil for "OFF", with one common connection. So they use low voltage wiring and the switches do not need to be in electrical boxes. They can also be used with a 12 volt DC battery if a transformer is not available. The switch relay portion is usually good for the higher current that larger light fixtures in expensive houses would have.
I have not checked to see if the items are still available at electrical supplier sources.
The benefit of the wired connection, instead of wireless, is that it is not hackable, nor can it be monitored from outside.
There might be a solid state version available but it would not offer any benefit aside from being newer.

 

The 24 volt impulse relays have one coil for "ON" and a second coil for "OFF", with one common connection.

The ones I use have only one coil, and a mechanical flipflop that holds the contacts either open or closed after coil power is removed. To be clear, I am *not* seriously recommending this approach for this application.

ak

 

The ones I use have only one coil, and a mechanical flipflop that holds the contacts either open or closed after coil power is removed. To be clear, I am *not* seriously recommending this approach for this application.

Generally this type often only has one coil, one pulse will close the relay and it is magnetically retained, power can be removed, and an opposite polarity pulse will releases it.

 

Hi,

Called a "latching relay" and I have used a few in the past.
The simple ones come with one coil or two coils. The two coils re easier to use in most cases because then you don't have to reverse the polarity.
You could have one button for 'on' and one button for 'off', then you would also know (or at least presume) the state of the lamp, on or off.

 

The ones I use have only one coil, and a mechanical flipflop that holds the contacts either open or closed after coil power is removed. To be clear, I am *not* seriously recommending this approach for this application.

ak

I would not consider using an alternate action control relay in any application.
In addition, it violates the code requirement that all devices have defined on/off indications. The alternate action of a pull-chain light switch is indicated by the light being either on or off.