| Electronics > Projects, Designs, and Technical Stuff |
| 3 switches, 7 lamps (no solid state) |
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| 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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