Author Topic: 3 switches, 7 lamps (no solid state)  (Read 3728 times)

0 Members and 1 Guest are viewing this topic.

Offline CyberdragonTopic starter

  • Super Contributor
  • ***
  • Posts: 2676
  • Country: us
3 switches, 7 lamps (no solid state)
« on: February 27, 2019, 05:19:35 pm »
i'm trying to come up with a system to switch 7 lamps on (indevidually) with 3 spdt switches and relays (just for funsies).

I'm trying to figure out the most efficient wat to do it. Getting the light to switch on when all switches are on is easy, when all switches are on, none of the secondary switch contacts have power which shuts of a spdt relay that disconnects the common from most lamps and connects it to the remaining lamp. Each switch is connected to a light through the nc contacts of other relays.

What I'm still trying to figure out is the logic that drives the other three lamps.

Aslo, the current circuit requires the same voltage for coils and lamps. So I'd have to have a different circuit using dual pole relays for different voltages (IE LV coils and mains bulbs).
« Last Edit: February 27, 2019, 07:43:14 pm by Cyberdragon »
*BZZZZZZAAAAAP*
Voltamort strikes again!
Explodingus - someone who frequently causes accidental explosions
 

Offline Nusa

  • Super Contributor
  • ***
  • Posts: 2418
  • Country: us
Re: 3 switches, 7 lamps
« Reply #1 on: February 27, 2019, 05:55:59 pm »
If by lamps, you mean LED's, check out charlieplexing. 3 pins can control 6 led's, 4 pins can control 12.

If you mean something higher wattage/voltage that requires a relay, you won't be able to make do with less than one relay per lamp. Not if they're to be independently controlled.

As for input, there are 8 possible combinations of 3 switches. If you eliminate the all-off state, that leaves 7. If your microcontroller monitors the 3 switches and waits long enough (a full second after first switch change maybe) for you to pick your combination, you could specify which lamp to toggle status on. The all-off state could either mean no change, or turn everything off.
 

Offline CyberdragonTopic starter

  • Super Contributor
  • ***
  • Posts: 2676
  • Country: us
Re: 3 switches, 7 lamps
« Reply #2 on: February 27, 2019, 07:17:02 pm »
I should clarify ONLY spdt switches and relays (making this from scrap), for a demonstration of relay logic (no solid state allowed). The lamps can be whatever (maybe not even the same).

EDIT: It'll be AC, so polarity reversal is nonexistant.
« Last Edit: February 27, 2019, 07:21:34 pm by Cyberdragon »
*BZZZZZZAAAAAP*
Voltamort strikes again!
Explodingus - someone who frequently causes accidental explosions
 

Offline AlfBaz

  • Super Contributor
  • ***
  • Posts: 2187
  • Country: au
Re: 3 switches, 7 lamps (no solid state)
« Reply #3 on: February 27, 2019, 08:20:21 pm »
Is there a limit to the number of relays you would like to use?
If not the easiest way to do it would be each switch turns on 4 spdt relays, 12 in total. Then it's a simple matter of wiring the appropriate switches in series using binary weights assigned to each group of relays
 

Online Benta

  • Super Contributor
  • ***
  • Posts: 6420
  • Country: de
Re: 3 switches, 7 lamps (no solid state)
« Reply #4 on: February 27, 2019, 08:34:10 pm »
Nice little exercise  :)

You'll need 7 spst relays for the lamps, 3 spdt switches and 4 spdt relays for the additional logic.

 

Offline larrybl

  • Regular Contributor
  • *
  • Posts: 150
  • Country: us
Re: 3 switches, 7 lamps (no solid state)
« Reply #5 on: February 27, 2019, 08:48:09 pm »
000  0ff
001  lamp 1
010  lamp 2
011  lamp 3
100  lamp 4
101  lamp 5
110  lamp 6
111  lamp 7

Binary says it may ne possible with three switches and 7 relays, How to wire it up  :-//
 

Offline ebastler

  • Super Contributor
  • ***
  • Posts: 7375
  • Country: de
Re: 3 switches, 7 lamps (no solid state)
« Reply #6 on: February 27, 2019, 09:14:52 pm »
Easy. You only need three relays, each with 7 dual-throw contacts.  :P
You can even save money on the switches since they only need to be SPST.  ;)
 

Online Benta

  • Super Contributor
  • ***
  • Posts: 6420
  • Country: de
Re: 3 switches, 7 lamps (no solid state)
« Reply #7 on: February 27, 2019, 09:15:29 pm »
000  0ff
001  lamp 1
010  lamp 2
011  lamp 3
100  lamp 4
101  lamp 5
110  lamp 6
111  lamp 7

Binary says it may ne possible with three switches and 7 relays, How to wire it up  :-//

That is very basic and obvious. But the problems is that both switches and relays are SPDT. With DPDT switches, only the 7 relays would be necessary.
To emulate the DPDT switches, 4 extra relays are needed.

 

Online Benta

  • Super Contributor
  • ***
  • Posts: 6420
  • Country: de
Re: 3 switches, 7 lamps (no solid state)
« Reply #8 on: February 27, 2019, 09:17:45 pm »
Easy. You only need three relays, each with 7 dual-throw contacts.  :P
You can even save money on the switches since they only need to be SPST.  ;)

Too much Korn tonight?
 

Offline ebastler

  • Super Contributor
  • ***
  • Posts: 7375
  • Country: de
Re: 3 switches, 7 lamps (no solid state)
« Reply #9 on: February 27, 2019, 09:25:59 pm »
Too much Korn tonight?

Nah, it's only four in the afternoon here; I'm in the US at the moment.
(Which also implies a lack of Korn, but some Bourbon might do later today...)

But seriously, I don't think the OP specified the type of relay in his rules of the game, so my solution counts.  ;)
 

Offline CyberdragonTopic starter

  • Super Contributor
  • ***
  • Posts: 2676
  • Country: us
Re: 3 switches, 7 lamps (no solid state)
« Reply #10 on: February 27, 2019, 09:31:35 pm »
I made a circuit using 7 relays, but that's with the lamps and coils in the same circuits (so either low or mains).

Nice little exercise  :)

You'll need 7 spst relays for the lamps, 3 spdt switches and 4 spdt relays for the additional logic.


only 4 spdt? I tried using only 4 spdt and couldn't figure it out. note DPDT relays allowed)
« Last Edit: February 27, 2019, 09:33:26 pm by Cyberdragon »
*BZZZZZZAAAAAP*
Voltamort strikes again!
Explodingus - someone who frequently causes accidental explosions
 

Offline Nusa

  • Super Contributor
  • ***
  • Posts: 2418
  • Country: us
Re: 3 switches, 7 lamps (no solid state)
« Reply #11 on: February 27, 2019, 09:40:46 pm »
000  0ff
001  lamp 1
010  lamp 2
011  lamp 3
100  lamp 4
101  lamp 5
110  lamp 6
111  lamp 7

Binary says it may ne possible with three switches and 7 relays, How to wire it up  :-//

That is very basic and obvious. But the problems is that both switches and relays are SPDT. With DPDT switches, only the 7 relays would be necessary.
To emulate the DPDT switches, 4 extra relays are needed.
Strange, With 7 spdt relays, I can't see any need for more than 3 spst switches. With dpdt switches, you can make do with 4 spdt relays I believe.

It's easier to think of this as an 8 light problem, then simply eliminate one light when you're done.
 

Offline ebastler

  • Super Contributor
  • ***
  • Posts: 7375
  • Country: de
Re: 3 switches, 7 lamps (no solid state)
« Reply #12 on: February 27, 2019, 09:47:21 pm »
Assuming that DPDT relays are allowed, but only SPDT switches:
Three switches and three relays should be enough.
  • Switch 1 directly multiplexes the voltage to two channels.
  • Switch 2 controls relay 1 to multiplex those 2 to 4 channels.
  • switch 3 controls relays 2 and 3 to multiplex those 4 to 8 channels.
Use six SPDT relays instead if you want to avoid DPDT.
 
The following users thanked this post: Cyberdragon

Online Benta

  • Super Contributor
  • ***
  • Posts: 6420
  • Country: de
Re: 3 switches, 7 lamps (no solid state)
« Reply #13 on: February 27, 2019, 09:52:06 pm »
"DPDT relays allowed"
This is not what you originally wrote.  :--

In that case, 7 SPST for the lamps, and 2 DPDT relays for logic.

Edit: 7 SPST, not SPDT.
« Last Edit: February 27, 2019, 10:19:52 pm by Benta »
 

Offline Nusa

  • Super Contributor
  • ***
  • Posts: 2418
  • Country: us
Re: 3 switches, 7 lamps (no solid state)
« Reply #14 on: February 27, 2019, 10:13:34 pm »
Assuming that DPDT relays are allowed, but only SPDT switches:
Three switches and three relays should be enough.
  • Switch 1 directly multiplexes the voltage to two channels.
  • Switch 2 controls relay 1 to multiplex those 2 to 4 channels.
  • switch 3 controls relays 2 and 3 to multiplex those 4 to 8 channels.
Use six SPDT relays instead if you want to avoid DPDT.
Now take the next step and use switch 2 directly instead of using a relay. And if you decide to allow switch 3 to be 4pdt, you can eliminate all relays.
 

Offline ebastler

  • Super Contributor
  • ***
  • Posts: 7375
  • Country: de
Re: 3 switches, 7 lamps (no solid state)
« Reply #15 on: February 27, 2019, 10:15:35 pm »
Now take the next step and use switch 2 directly instead of using a relay. And if you decide to allow switch 3 to be 4pdt, you can eliminate all relays.

Of course. But the rules in the original post are pretty clear regarding the switches -- SPDT only.
There's room for interpretation regarding the relays.
 

Offline CyberdragonTopic starter

  • Super Contributor
  • ***
  • Posts: 2676
  • Country: us
Re: 3 switches, 7 lamps (no solid state)
« Reply #16 on: February 27, 2019, 10:27:28 pm »
"DPDT relays allowed"
This is not what you originally wrote.  :--

In that case, 7 SPST for the lamps, and 2 DPDT relays for logic.

Edit: 7 SPST, not SPDT.

You misread, I said only the switches had to be spdt. I would have specified spdt relays, I just said relays. Though I should specify common relays, so no 7 pole nonesense.

EDIT: I don't think relays for each light are needed. Ebastlers circuit has switches 2 and 3 isolated so they could be low voltage while only switch one sees mains, allowing for the use of low voltage relay coils.
« Last Edit: February 27, 2019, 10:34:48 pm by Cyberdragon »
*BZZZZZZAAAAAP*
Voltamort strikes again!
Explodingus - someone who frequently causes accidental explosions
 

Offline bsudbrink

  • Frequent Contributor
  • **
  • Posts: 409
  • Country: us
Re: 3 switches, 7 lamps (no solid state)
« Reply #17 on: February 28, 2019, 12:09:30 am »
Sorry for the ugly drawing, I don't have access to a real tool right now...
Anyway, is there any reason this wouldn't work:
 

Offline bsudbrink

  • Frequent Contributor
  • **
  • Posts: 409
  • Country: us
Re: 3 switches, 7 lamps (no solid state)
« Reply #18 on: February 28, 2019, 12:10:30 am »
By the way, omit "L0" as required.
 

Online Benta

  • Super Contributor
  • ***
  • Posts: 6420
  • Country: de
Re: 3 switches, 7 lamps (no solid state)
« Reply #19 on: February 28, 2019, 12:13:34 am »
On thinking a bit further, this can be reduced to two DPDT relays.

 

Offline ebastler

  • Super Contributor
  • ***
  • Posts: 7375
  • Country: de
Re: 3 switches, 7 lamps (no solid state)
« Reply #20 on: February 28, 2019, 12:27:38 am »
Sorry for the ugly drawing, I don't have access to a real tool right now...
Anyway, is there any reason this wouldn't work:

Clever. But the final stage will give you one brightly lit lamp and several glowing lamps (connected in series).
 

Offline ebastler

  • Super Contributor
  • ***
  • Posts: 7375
  • Country: de
Re: 3 switches, 7 lamps (no solid state)
« Reply #21 on: February 28, 2019, 12:28:49 am »
On thinking a bit further, this can be reduced to two DPDT relays.

Plus how many switches of which type?
 

Offline bsudbrink

  • Frequent Contributor
  • **
  • Posts: 409
  • Country: us
Re: 3 switches, 7 lamps (no solid state)
« Reply #22 on: February 28, 2019, 12:34:39 am »
Sorry for the ugly drawing, I don't have access to a real tool right now...
Anyway, is there any reason this wouldn't work:

Clever. But the final stage will give you one brightly lit lamp and several glowing lamps (connected in series).

Ah.  Shoot, I was thinking LEDs.
« Last Edit: February 28, 2019, 12:39:02 am by bsudbrink »
 

Online Benta

  • Super Contributor
  • ***
  • Posts: 6420
  • Country: de
Re: 3 switches, 7 lamps (no solid state)
« Reply #23 on: February 28, 2019, 12:47:10 am »
On thinking a bit further, this can be reduced to two DPDT relays.

Plus how many switches of which type?

Three SPDT switches as specified.  :)

 

Offline ebastler

  • Super Contributor
  • ***
  • Posts: 7375
  • Country: de
Re: 3 switches, 7 lamps (no solid state)
« Reply #24 on: February 28, 2019, 01:08:22 am »
On thinking a bit further, this can be reduced to two DPDT relays.
Plus how many switches of which type?
Three SPDT switches as specified.  :)

Hmm... I can’t figure out how that would work. Cards on the table, please!
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf