SPST Switch Change State On Three Relays

[rickdunna]

I am working on a project which requires I use (1) SPST switch to change states on (3) relays, maybe (4).

I have an old lamp that has a floor switch (SPST) and I want to put a newer socket in it that supports 3 way light bulbs. I can add the extra wire to it. I have searched all over for a 3 way pushbutton switch, but there doesn't seem to exist, so I thought I could do it with the existing switch and relays.

Maybe this isn't the best way, and I am open to any solution.

It needs these different states:

Off Off Off
On Off Off
Off On Off
Off Off On

Let me know what you think.
Thanks In advance for the help

 

[logbook]

I'm not sure what you mean by "3 way light bulbs" but your state table is pretty clear. You should be able to find a push button switch bank second hand in an electronics shop. These are very historic so you probably won't find them new.

Doing this electronically using a shift register is probably more trouble than it’s worth in terms of power supplies. Likewise using a PIC micro-controller. So the first option has to be the dedicated switch bank.

You could probably wire up a shift register in relays if you were really keen. It would be an interesting intellectual challenge if nothing else.

 

[MacGyverS2000]

For the trouble you're going to go through, I'd just junk the lamp and buy a new one. If you insist on going down this road, how about replacing the SPST with a 4-detent rotary knob that controls 3 relays...


Dan - Owner

http://www.Hi-TecDesigns.com

 

[logbook]

I've just been to B&Q and Homebase on another mission. They both sell three SPDT switches in one standard sized switch plate for £3. You can wire these switches in series to give only one lamp on at a time (albeit in a strange sort of priority encoder way).

 

[VEBill]

A typical 3-way light bulb has two filaments wired to three contacts.

The state table would be thus (example):

Off Off = off
On Off = 50w
Off On = 100w
On On = 50w + 100w = 150w

You'll need a new socket to hold the 3-way bulb. The socket that holds the 3-way bulb can be bought with the little rotary switch built-in.

Any extra series switches can be used to turn the whole thing on and off, but not select the state.

Another option (maybe?) would be to stick with a normal bulb and somehow wire in a 'floor dimmer' in place of the floor switch.

 

[OperaHouse]

The truth in the truth table........ Your table is wrong!

It needs these different states:

Off Off
On Off
Off On
On On

Typical 3 way lamps are two filaments with something like a 35W and 60W internals giving 35W, 60W, 95W.

3 way lamps are going out of style. There are push button light dimmers you could modify. I could do it with relays, but I don't think it would fit under the base of a lamp.

 

[VEBill]

Beatya. ;-)

 

[logbook]

Ok, so I never heard of that type of bulb (except in cars where the main and dipped beams are in the same envelope). Mea culpa.

Given the new truth tables, surely all we need is a standard switch plate with two SPST switches in it. There is no "wrong" combination that causes problems. Each switch controls one element, independant of the other.

 

[itsmoked]

logbook; You must be a compact fluorescent baby. That type of socket/lamp is dying rapidly now as they aren't usable with CFs.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[jraef]

...they aren't usable with CFs.

Minor correction... yes they are, but they just become 1 way lamps with 2 Off positions.

Back to the original question:
Rickunna,
If you accept the above postings that correct your logic to what 3-way bulbs really work like, then the switch is a very standard commodity called a push-button 3 way lamp switch.

http://www.surplussales.com/Electrical/LampSwitches-2.html

If you have some other agenda that requires the logic that you posted, then you will need to build relay logic to accomplish that. In that case, I would just go and buy a programmable "smart relay" like the Siemens LOGO and do the logic in programming.

 

[zeitghost]

3 way lamp?

Never heard of these in the UK.

What sort of base do they use?

 

[VEBill]

An extra ring-like contact between the usual two (closer to the big thread, staying away from the button).

 

[jimkirk]

Try looking up "Bulb Boss". I'm not sure they're still being made. They are an insert, about 5 mm thick, that go between the tip contact of an incadescent bulb and the socket.

Turn the lamp on, and the bulb soft starts (to extend filament life) to full on. Flick the bulb off and on, it goes to about 1/2 bright. Flick it off and on again, it goes to about 1/4 bright. Flick it one more time it goes to a dim night-light glow. Flick it again and the cycle starts all over again.

If it has been off long enough, about 20 seconds, it resets to turning fully on at the next power application.

Dimmable fluorescents give two fully on and two fully off settings. At least the ones I tried did.

They also made similar devices that would turn the controlled lamp off after a preset time depending on the switch flicks, and one that had a mode that would flash the light for an emergency signal.

They were from Beacon Light Products, which doesn't seem to have a web site anymore. (

http://www.beacon-light.com

seems to be dead) You might still be able to find their products on e-bay or surplus web sites.

Oh, and regarding three way bulbs, they're coming back into style, in the form of compact fluorescent bulbs. Probably due to the dimming issues they have.

 

[rickdunna]

Thanks for the help and additional feedback.

I will take what you gave me and apply it.

Thanks Rick