Alternating Switch

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fluoronator
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Alternating Switch

Post by fluoronator » Tue Mar 01, 2011 5:55 pm

I have a switch near my back door that operates a light in my backyard shed. I want to add a floodlight to the outside of the barn that I can operate from the house but I don't want to run another wire. I would like to use a circuit what would cause the floodlight to turn on "every other" time that the switch is turned on.
It would operate like this.
(start)
Switch on = barn light on, flood light remains off.
Switch off = Lights off.
Switch on = barn light and flood light on.
Switch off = Lights off.
(repeat)
The only way I can think of to do this requires building a circuit board with a logic circuit and a power supply such as a battery to maintain the state when the power is off. I'm sure there is a much simpler way. I have a couple of duplex latching relays on hand... Any ideas?

gerty
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Re: Alternating Switch

Post by gerty » Tue Mar 01, 2011 8:35 pm

You might consider x10
http://www.x10.com/promotions/tm751_rem ... l?TWENTY11
I've used it before, it's not 100%, but for your needs it should be fine.

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dacflyer
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Re: Alternating Switch

Post by dacflyer » Wed Mar 02, 2011 5:41 am

i seen at home cheapo ( home depot ) in the ceiling fan area, they had a light / fan combo switch unit that would do such a thing. you flip the switch a number of times to activate the fan or the light...or both. but the fan speed was not controlled.
so this might be just what your looking for..
if not then the X-10 Home controls would be best.
i think radio shack still sells them, ebay has tons of that stuff..
look for X-10 or HOME POWER

fluoronator
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Re: Alternating Switch

Post by fluoronator » Wed Mar 02, 2011 5:47 am

Both sound like good ideas. I think I've come up with a solution that is overkill but it uses items that I have on-hand. I have one of those cheap little Koyo PLCs I'm going to use for the logic and the mechanically latching relay will by my memory when the power is off. I really hate to waste a perfectly good PLC on such a project but it's just sitting in a drawer in my shop :(

Dean Huster
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Re: Alternating Switch

Post by Dean Huster » Mon Mar 07, 2011 8:01 pm

If the 120 vac is supplied to the barn and the wire running from barn to house is only to the switch, it shouldn't be difficult. On the other hand, if the 120 vac is being supplied at the house and switched to the barn, the only time you'll have power to the barn (and hence to any control circuitry) is when the switch is ON. While OFF, the barn power is dead. You'll need battery backup or some other method of supplying standby power to the barn while the light switch is off if using electronic control logic. However, there is the possibly that you might be able to find an old stepper relay (or some latching relays) that will help you do the job you want without power 24-7 to the control circuits.
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

R.I.P.

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Lenp
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Re: Alternating Switch

Post by Lenp » Sat Mar 12, 2011 7:02 am

Flourinator, here's yet another thought....

Use a PIC, Stamp..whatever that is powered by a wall wart from the switched circuit.
Each time it is powered it reads a memory location and outputs to a related pin. The pin powers either an SSR or a driver and relay to control the loads.
In your case only two outputs are needed.

As an illustration, ...
------------------------------------------------------------------------------------------------------------------------
(NOTE: The memory location being used is EPROM or other NVR memory, not volatle ram.)

Program Start
The first time the processor powers up there is a small delay then it reads a memory location
Finding a 0, it turns off pin 2 switching off load #2 and turns on pin 1 switching on load #1
Then it writes a 1 to the memory location

The second time the processor powers up there is a small delay then it reads the memory location
Finding a 1, it turns off pin 1 switching off load #1 and turns on pin 2 switching on load #2
Then it writes a 3 to the memory location

The third time the processor powers up there is a small delay then it reads the memory location
Finding a 2, it turns on pins 1 and pin 2 switching on on loads #1 and 2
Then it writes a 3 to the memory location

The fourth time the processor powers up there is a small delay then it reads the memory location
Finding a 3, it turns off pins 1 and pin 2 switching off loads #1 and 2
Then it writes a 0 to the memory location

The program then returns back to the start

------------------------------------------------------------------------------------------------------------------------
This basic shell could be expanded to more circuts and features, like even a lights flash mode!

Len
Len

“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)

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