# Reverse Lightning - 120v relay



## TommaHawk (Sep 18, 2007)

*Reverse Lightning - 120v relay (diagram included)*

Check me here...

My 3-channel color organ (lightning machine) runs on 120vac. To hack in a reverse-flicker (the room lamp/other lights flicker off when the lightning lights fire on) I picked up a standard 120vac DPDT relay and socket. I'll splice the coil contacts to one of the lightning channels, so I assume:

1.) I must drive that channel's lightning bulb with the NO contacts (pins 3&4) _piece of cake_
2.) The room lamp is driven off the "other" 120vac power-in contacts (pins 5&6) and the NC contacts (pins 1&2) _another piece of cake_

But...

3.) Is it alright to pigtail the 120vac in to _both _the circuit board and pins 5&6 on the relay, or must I have a totally separate 120vac line into pins 5&6 (assuming my room lamp is 120vac)?

I think I can pigtail without a problem but...
View attachment 402


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## Otaku (Dec 3, 2004)

TommaHawk,
Here's the pinout for your relay:
1 + 2 are the NC pins
3 + 4 are the NO pins
5 + 6 are the Commons
A + B are the coil pins

To set up a reverse flicker for the house light, wire the Coil pins (A+B) in series with one of the lightning bulbs (pick a channel). The coil shouldn't pull much in the way of wattage so you won't notice a drop in brightness. Now the relay will energize whenever that channel is active. Wire the power to the house light in series with pins 1 and 5 OR 2 and 6. The NC contacts will open when the channel goes active, switching off the power to the house light. Let me know if you have any questions. Remember that you're working with 110VAC and be sure to insulate the connections.


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## TommaHawk (Sep 18, 2007)

What was I thinking? Little embarrassed - must be pretty tired to list out my pins as I did above. 1&5... gotcha, that makes more sense (remembering that this is a DPDT). I'll try this ASAP, and if it works, I'll post a diagram of the circuit. If not, well, I'll post a picture of the charred remains.:smoking:

I'll pigtail the power to both components rather than bringing in a separate 120vac line - the power draw of the lamp and circuit bulbs are pretty minimal, especially since one will be active while the other is not.


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## Otaku (Dec 3, 2004)

The house light will have it's own power, right? The only things the color organ channel should be powering are the relay and the lightning bulb.


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## TommaHawk (Sep 18, 2007)

So, the lamp will have its own power, driven through pins 1&5? I don't have to power the lamp separately (though driven through pins 1&5)? Shouldn't the color organ power the lamp through the NC contacts the whole time?

Here's my thinking - that particular channel only receives power from the circuit when the conditions are right (like sound in the high end of the spectrum). I'll need to power the room light separately with it's own 120vac plugged into pins 1&5 (NC), so when that channel is activated the relay will cut to the NO pins thus cutting power to the lamp?


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## Otaku (Dec 3, 2004)

You got it. Only one of the two wires from the lamp will be connected in series to pins 1 and 5. The same goes for the color organ channel wires. For the relay: one of the two wires from the color organ will go to pin A, a wire goes from pin B to the lightning bulb fixture/socket, the return goes from the other connection of the socket back to the color organ. For the lamp: one wire from the plug goes to pin 1, a wire goes from pin 5 to the lamp. When you plug everything in, the lamp will be on, and will go off when the channel is active.


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## TommaHawk (Sep 18, 2007)

Ah ha! Yes, I have it. Thanks your your sanity check.

But again, if I wanted to have a single power cord powering the lot, couldn't I pigtail that one wire from the power cord to pin 1 and the organ? What I'm picturing is a relay switching power on and off to another socket (that the lamp is plugged into), sort of an all-in-one solution. Plug your three lightning bulbs into the three channels, and a lamp into the "fourth" socket (sorry - maybe I should have mentioned this earlier). That would work, yes?


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## Otaku (Dec 3, 2004)

Yes, that should work. Just be sure that the color organ won't be turning off it's own power.


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## gmacted (Jan 18, 2006)

Sorry to chime in so late, but I would not use a mechanical relay for this application. Mechanical relays aren't really designed to be switched on and off rapidly. They have a "mechanical life" and will cease to work after so many operations. It may work for a while (the switching speed may be too great however for the relay), but it will fail over time.


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## Otaku (Dec 3, 2004)

gmacted is right about that. If you can use an SSR (solid state relay) you'll definitely get longer lie. They're pricey, though, the one you'd need would go for ~$25-30.


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## gmacted (Jan 18, 2006)

Otaku said:


> gmacted is right about that. If you can use an SSR (solid state relay) you'll definitely get longer lie. They're pricey, though, the one you'd need would go for ~$25-30.


That's definitely the way to go.


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## TommaHawk (Sep 18, 2007)

Absolutely - I did consider a SSR, but really the amount of time I'd _actually _be running the thing over the next few years, and given this relay has an expected life of >500k cycles (under normal conditions), I figured I'm willing to spend another $9 (probably $12 by then) on a new mechanical relay should this one fail before

a) I just have no further use for a 3-channel organ
b) my daughter uses this fun little project as a submarine in the pool

Any longevity I'd lose in this application is, I guess, within my standard deviation of required maintenance cycles. Plus using a socket makes this a plug&play hack, which I like.

Do they make sockets for SSRs?


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## Otaku (Dec 3, 2004)

TommaHawk said:


> Any longevity I'd lose in this application is, I guess, within my standard deviation of required maintenance cycles.


You running a 3- or 6-sigma process on this application? LOL


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## TommaHawk (Sep 18, 2007)

Sure.


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## gmacted (Jan 18, 2006)

TommaHawk said:


> Do they make sockets for SSRs?


Off the top of my head, no, but they could. They're very reliable.


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## TommaHawk (Sep 18, 2007)

For you lightning machine fans - a simple diagram of the reverse-lightning wiring:









To walk you through the build, from the top:
- Acquire a lightning machine. I used this: http://www.goldmine-elec-products.com/prodinfo.asp?number=C4530 but this is also very popular: http://www.frightcatalog.com/Halloween-Props/Lighting-FX-1408006/
- Acquire a 120VAC relay (and socket if you prefer). Got mine at RS.
http://www.radioshack.com/product/index.jsp?productId=2049721&cp=2032058.2032230.2032277&allCount=23&fbn=Price%2F%246.00+-+%249.99&fbc=1&fr=StorePrice%2FRSK%2F00000600%2F00000999&parentPage=family (similar to this)
http://www.radioshack.com/product/index.jsp?productId=2062476
- The regular lightning outlet will be fed by two wires coming from the circuit board (tan block). Cut one of these wires and splice the ends to the relay coil pins A and B, respectively. Your coil pins may be labeled 7 and 8 instead of A & B...
- Acquire a basic outlet to install as the reverse-flicker outlet.
- The power cord feeding your lightning machine will be soldered to the circuit board (shown red and black in my diagram). Cut this (or desolder) and split or "pigtail" each wire of the cord into two, creating a "Y" on each wire.
- Solder one end of each "Y" to the circuit board, and the other ends to relay pin #5 and one "side" of the reverse-flicker outlet, respectively.
- Solder a wire to relay pin #1 and the "other side" of the reverse-flicker outlet.
- Secure all connections and hardware.

To walk you through the thinking:
Adding a reverse-flicker outlet as described will enable you to have a separate bulb (or whatever) plugged into the lightning machine that will be "on" until the circuit sends power to the lightning socket. Plug the lightning machine in and power is sent through the normally closed contacts of the relay (#1 & #5) powering the outlet. Lightning sound is then fed to the machine: when this happens, the 120VAC sent to the lightning bulb also activates the coil in the relay, physically moving the contacts to the normally open position thus killing power to the other socket in a reverse-flicker effect. Very cool!

I should reiterate - the lamp (or whatever) will flicker off in sequence with the lightning flashes. It will not just "stay off".

This is a DPDT relay (dual pole, dual throw), which means there are two separate sets of contacts inside. I use pins #1 and #5 here, but you could use #2 and #6 if you like - just be sure you use them in this sequence: #1 and #5 _OR _#2 and #6.

Other ideas:
I actually use this with a 3-channel lightning machine and have the reverse-lightning socket attached to the high-end channel. Doing this, people will see and hear 3-stage lightning like normal but the lamp only flickers off part of the time - this way it's not so much of a directly inverse relationship. Or, if you were to use this without the lightning bulb (just a lamp plugged into the reverse socket) and without speakers, you could feed the lightning audio in like normal, and your room lights would flicker only every-so-often which could be a cool effect.

If you were to remove the relay itself from its socket (not sure why you'd want to - this would totally disengage the reverse-flicker socket) you'd need to put a jumper wire between pins A & B of the relay socket to allow that lightning channel to fire.

Please see the discussion in this thread for other considerations regarding this approach (lifespan, etc.). Remember you're working with 120 volts here! Do this at your own risk - if you're not comfortable with electronics and proper safety precautions, _don't attempt this project._


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## fritz42_male (May 5, 2009)

I bought 10 SSRs off this guy and they are good value:

http://cgi.ebay.co.uk/solid-state-r...s_ET?hash=item3ef8a7e45e&_trksid=p3286.c0.m14

Alternatively this one:
http://cgi.ebay.co.uk/CRYDOM-SSR-38...s_ET?hash=item2ea7f07d1e&_trksid=p3286.c0.m14


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