Electronics > Projects, Designs, and Technical Stuff
3 switches, 7 lamps (no solid state)
Cyberdragon:
I made a circuit using 7 relays, but that's with the lamps and coils in the same circuits (so either low or mains).
--- Quote from: Benta 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.
--- End quote ---
only 4 spdt? I tried using only 4 spdt and couldn't figure it out. note DPDT relays allowed)
Nusa:
--- Quote from: Benta on February 27, 2019, 09:15:29 pm ---
--- Quote from: larrybl 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 :-//
--- End quote ---
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.
--- End quote ---
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.
ebastler:
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.
Benta:
"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.
Nusa:
--- Quote from: ebastler 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.
--- End quote ---
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.
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