Circuit to Switch Between Two AC light sockets from a single light socket plug. - Page 1
Forum section: electronics / general

author: jonovid
author_rank: Super Contributor
timestamp: March 30, 2024, 02:48:44 am
content: using the house light switch as a remote control to switch between Christmas lights and the regular porch light.looking for a light socket switch circuit that will switch between two light sockets in a socket plug switch circuit.light socket switch circuit must have a 240 volt AC to low voltage DC power supply to power the circuit and its DC relay.a capacitor in the circuit holds a charge when the light switch is switched on but the relay is Not triggered.circuit must hold this state indefinitely if the AC power is Not disrupted.however if the light switch is switched off and then back on in less then two seconds the relay is triggered.when the relay is triggered it will latch on indefinitely.the circuit must re-set its self when the light switch is off for more then five seconds.something for next years holiday seasonthe purpose of the circuit is to switch between two light sockets in a light socket plug.using the house light switch on the wall as a remote control. for Christmas lights.the circuit is for a max of 200Wif a plug socket is one side of the switch. it must have all three pin slots But the its ground pin slot is Blocked so onlya double insulated Christmas light plug under 200 watt can use it.also the weight of the double adapter unit must not exceed the weight limit of the light socket it is plugged in to.the reason for this post is the circuit not the formfactor of the double adapter unit.ideas and suggestions as to how to best accomplish this type of socket switch circuit?I was considering a modified relay latching circuit using bipolar transistors & a AC to DC LED driver light power supply to power it?I was unable to find a latching switch circuit on-line that would work as described.detect if the power had been disrupted. so to remote control the relay.the formfactor I had in mind was this using PVC tube and some light fittings for the ends.

author: themadhippy
author_rank: Super Contributor
timestamp: March 30, 2024, 03:02:37 am
content: Theres a much simpler option,if you can find one ,a single BC plug to 2 BC sockets with a built in pull cord to switch between the 2

author: soldar
author_rank: Super Contributor
timestamp: March 30, 2024, 01:46:09 pm
content: The concept exists with light bulb sockets for porch use that function normally but when switched off for just a moment and then on again go into dusk mode so the light turns on in the dark and off during daylight.It should be quite easy to design and build such a circuit. Basically just a bi-stable which starts normally in one state but starts in the other state if a capacitor still has charge above a certain threshold.

author: jonovid
author_rank: Super Contributor
timestamp: March 31, 2024, 11:41:46 am
content: Quote from: soldar on March 30, 2024, 01:46:09 pmI have the rest of the year to work on the switch circuit. I had in mind it be a 3 bipolar transistor job or a better op-amp design.a small cheap 5 or 15 volt DC from AC driver light switch mode power supply module will power it. with an output relay suit.I looking for circuit suggestions others had used and are known to work as reliable. the whole circuit needs to fit inside a light bulb sized plastic enclosure.about the size of 2 match boxes. of course a fuse will be on the AC input.

author: soldar
author_rank: Super Contributor
timestamp: April 05, 2024, 01:57:31 pm
content: I would have to think about it and design a circuit but decades ago I used to make bistables with a couple of gates cross-connected. You can probably do it with a CD4011.Maybe if I can find some time i can try it.

author: EPAIII
author_rank: Super Contributor
timestamp: April 05, 2024, 06:45:13 pm
content: The first problem that I see is you are using AC as a control signal. Yes, sure I know it is done, but DC is a lot easier. Have you considered a DC power supply at the inside switch location then use that DC for both the control signal and to power the lights? Seems to me that would make things easier.

author: soldar
author_rank: Super Contributor
timestamp: April 05, 2024, 09:18:41 pm
content: Here is a rough idea which is probably wrong and needs polishing. This is how I used to do these things 40 years ago so I am a bit rusty.CD4011 has 4 NAND gates, Gates A and B form a RS bistable of pins 1 and 5 whichever goes low last will determine the state of the bistable.Gates C and D are connected as inverters and so whichever goes high last will determine the state of the bistable.In normal operation the Reset input is last and so the bistable is reset.When power has been cut for just a moment then the Set input lasts longer and the bistable is set.This is a very general idea which needs developing and testing.

author: soldar
author_rank: Super Contributor
timestamp: April 07, 2024, 11:36:14 pm
content: Come to think about it, probably a single 555 in bistable mode can do it. It is, in essence, an RS bistable. Whichever input is asserted last will determine the stable state of the RS.

author: soldar
author_rank: Super Contributor
timestamp: April 08, 2024, 01:49:41 pm
content: Here is a basic idea.The two inputs to the RS bistable, set and reset, have different time constants and the last one to go up is the one that prevails.Normally, starting from zero, reset has a longer time constant and goes up last and the bistable is reset and remains like that.With only a short cut in power C1 discharges through D1 and starts with the same RC time constant as before but C2 did not have enough time to discharge so it starts already up. Set reaches "up" later and the bistable is set and remains like that.I think it is possible that with this and a single 555 connected as a bistable it might work.

author: jonovid
author_rank: Super Contributor
timestamp: April 09, 2024, 07:47:53 am
content: Quote from: soldar on April 08, 2024, 01:49:41 pmits the order of charge beteen C1 and C2 on boot-up that must determined the latch state that the circuit willhold indefinitely.

author: soldar
author_rank: Super Contributor
timestamp: April 09, 2024, 07:57:30 am
content: Quote from: jonovid on April 09, 2024, 07:47:53 amThat is the way it should work. What makes you think otherwise? That is what a bistable does.