# Need Help With 12 VDC Wiring Problem.



## jimcosta (Jun 11, 2017)

I am planning to mount two 12 VDC truck lights 15 feet high after a 30 foot run of heavy braided outside light wire.

I plan to have two means of turning the lights on: a light switch and a trip wire.

I intend for* both lights to come on by either method *to insure that at least one stays on if fired upon.

I want to use just a two strand wire (extension cord type) to the lights.

I will first run the *negative* wire directly to both lights.

*Question #1:*

I plan to run a *positive* wire to the light-switch
and another *positive* wire to the trip-wire switch,
and then join the trip-wire *exit-wire* to the *exit wire* from the light-switch.

Will this be a problem if first the light-switch is turned on and then later the trip-wire goes hot?

*Question #2:*

I had planned to wrap two wires around both sides of a wooden clothes pin and use a plastic tab as the pull pin.
Is there a better/simpler way of doing this?

See the PDF drawing attached. Thanks.


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## dwight55 (Nov 9, 2012)

You are OK Jim, . . . no problem other than the fact that you will have to go out and reset the trip switch if something trips it.

May God bless,
Dwight


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## 1skrewsloose (Jun 3, 2013)

Back in the day we used an old set of points to fab up kill switches when racing. May be a bit more durable than the clothes pin. Also when I was in school we would mock up a desktop circuit to checked that everything worked.


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## jimcosta (Jun 11, 2017)

*Thanks Dwight.* Actually the trip wire is inside our guardhouse. The wire will be pulled by a guard, and by timing lengths of cord, will fire a shotgun alarm behind the intruders, then drop a camp tarp hanging over the gate and at the same time turn on the floodlights. Thus the intruders will have their backs to the guards and blinded if the turn around even though they will have been ordered not to do so.


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## jimcosta (Jun 11, 2017)

*Iscrewloose: * So what I need to do is have the lead in attached to the top of the plug and solder the exit wire to the wrench attachment area?

Won't this just give an arc and not a continuous circuit through the gap?
Or would a covered piece of wire be set in the arc and when pulled drag up a knotted bare wire section bridging the arc?

I am confused as you can see.


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## 1skrewsloose (Jun 3, 2013)

On a set of old automobile points the wire connects to each side of the contacts. When the plastic is pulled it completes the circuit and turns on the lights and what not. On motorcycles we used it in reverse. It was used to break the circuit, stop the engine. You'd still have to manually reset the plastic between the contacts.

The points are normally closed by a flat spring, once the plastic is removed you have a closed circuit. 
When the points are closed it acts like a solid piece of wire, they operate in normally closed condition.

The same principle as your clothes pin idea only using points, don't over think it. hope this helps.


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## jimcosta (Jun 11, 2017)

Now I've got it. Its not the spark plug but the points. Thanks.
I assume the points are generally rated for a *continuous* 12 volt current, right?


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## jimcosta (Jun 11, 2017)

I was doing some thinking and also came up with a single knife switch ($5 at Amazon).

The tarp on the gate will be attached to a horizontal 2 X 4 on it's top.
It will have a looped paracord hanging over the top bar of the gate at each end of the gate.

At each location there are two 1 inch angle brackets screwed to the gate pipe, with a one inch gap between them.
A nail will slide between the two angles with a longer cord tied to the head of the nail.
When the cord is pulled the nails will release the loops, dropping the board and tarp so our guards get a better view of the intruders.

Perhaps I might tie a weight on the knife switch handle with a loop in the weight string held in place by the angles described above. Then when the main cord is pulled the knife switch will close.

*Your thoughts?*


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## 1skrewsloose (Jun 3, 2013)

The points will handle continuous 12v no problem, when in a 8 cylinder car running at 3000 rpm they open and close 24000 times a minute, they would only come into play at the onset of intrusion, for as long as it lasts. A little hard for me to visualize your setup, thought you said a guard would trip the switch. I believe in KISS. Guess you could go either way, guard tripping the switch or the gate doing double duty with the tarp and turning on the lights. If the gate fails you'd loose lights, though.


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## 1skrewsloose (Jun 3, 2013)

Upon further thought, nothing wrong with having redundant systems for security purposes. Maybe use both?


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## SOCOM42 (Nov 9, 2012)

You can set all your trap switches to run in parallel then into an SSR.

The SSR will handle plenty of load with nothing for a load on the regulating or switch side.

This is an SSR;









IF you use one get the right voltages on both sides.

Which I believe is 12 VDC/ 12 VDC.


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## 1skrewsloose (Jun 3, 2013)

@SOCOM42 An even better idea, forgot about solid state relays. How could I forget them, used extensively in the IMM's I used to work on!

IMM= Injection Molding Machine


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## jimcosta (Jun 11, 2017)

*1screwloose.* There will be just one string being pulled with one shorter string teed off at the end in the guardhouse and one shorter string teeing off at the gate end.

The gate end (30 feet away) will be timed to go off a second after the shotgun alarm is fired (100 feet away). In the guardhouse, the short teed off light end (2 feet) will also execute one second or so after the shotgun alarm is fired. This will insure that the intruders have first turned their entire bodies around completely. Then action occurs behind them again but at the same time they are being ordered to "drop em".

Therefore, if a single intruder approaches the gate and the guard does not wish to teach them our entire defensive plan, the guard can simply flip the light switch on for a look see.
Otherwise, the guard can slow pull the long main 100 foot cord about two feet, setting off all three stations as it comes through the PVC pipe it is in.


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## 1skrewsloose (Jun 3, 2013)

Sounds like you have a plan, Good Luck!


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## jimcosta (Jun 11, 2017)

Our group does not have an electronics techee type in the membership. Socom42, what you suggest probably is good but it is way beyond me.
I only know ropes and knots.


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## jimcosta (Jun 11, 2017)

Thanks for the help gang!


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## pakrat (Nov 18, 2012)

jimcosta said:


> Now I've got it. Its not the spark plug but the points. Thanks.
> I assume the points are generally rated for a *continuous* 12 volt current, right?


12 volts does not mandate a specific current. It's depends on the load at that voltage. Divide the total wattage of the lights that will be powered by the circuit by 12 (the supply voltage). The result will be the current (in amps) that will be moving through the points.

I've read that automotive points are rated for 4 - 6 amps, depending on the size of the ignition system they're designed for. You multiply the voltage (12) times the amps ( 4 or 6) to get watts. At 12 volts, that would accommodate somewhere between 48 and 72 watts maximum load through the points&#8230; not really great power for security lights.

You may want to consider powering the lights through a basic automotive relay that's rated for higher current load (say 20 amps/240 watts at 12 volts) and use the trip-wire and switch circuit to open and close the low current side of the relay. You could use lighter wire (like 18ga or 20ga bell wire) in the switch and trip circuit because the current to the control side of the relay would be much lower. Easier to hide, cheaper to run.


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## Mad Trapper (Feb 12, 2014)

For a switch on a trip wire, a mouse trap would work fine. Solder 1 wire on the bail/mouse hitter and the other fasten where it strikes. Could get fancy and put some copper flashing where it strikes and solder the wire to it. The gauge/thickness of a trap bail should handle any current you'll need. Or use a rat trap

You could use a very thin/invisible trip wire with this, 4-6 lb fishing line.

P.S. set up your trips where things like rabbits, woodchucks, foxes, deer are not going to set things off.


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## Slippy (Nov 14, 2013)

Good luck @jimcosta

Electricity is not my thing...:vs_bulb:


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## modfan (Feb 18, 2016)

You can also look for an old style thermostat and take the mercury switch out. It will be really sensitive to movement.


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## MountainGirl (Oct 29, 2017)

Slippy said:


> Good luck jimcosta
> Electricity is not my thing...:vs_bulb:


So...you're back to gravity-fed pikes, then?


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## Elvis (Jun 22, 2018)

1skrewsloose said:


> On a set of old automobile points the wire connects to each side of the contacts. When the plastic is pulled it completes the circuit and turns on the lights and what not. On motorcycles we used it in reverse. It was used to break the circuit, stop the engine. You'd still have to manually reset the plastic between the contacts.
> 
> The points are normally closed by a flat spring, once the plastic is removed you have a closed circuit.
> When the points are closed it acts like a solid piece of wire, they operate in normally closed condition.
> ...


1Screwsloose's method sounds like a winner to me, and the points will already have screw holes to mount them securely.


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## Slippy (Nov 14, 2013)

MountainGirl said:


> So...you're back to gravity-fed pikes, then?


Hey MountainGirl! Welcome back!

I hope you did OK while in Solitary! I put so much childish and moronic graffitti on those jail cell walls, I hope @Denton had them white warshed! :vs_lol:

Like I always say, Do the Time, Don't Let The Time Do You! :vs_smile:


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## Mad Trapper (Feb 12, 2014)

MountainGirl said:


> So...you're back to gravity-fed pikes, then?


Gravity is free!


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## jimcosta (Jun 11, 2017)

One last question.

Can someone show me a relay I can order to cause the 12 VDC lights to blink on and off once the power is turned on? Thanks.


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## SOCOM42 (Nov 9, 2012)

You need an automotive directional light thermal relay to do the blinking.

Most common relays are a one shot deal, delay on either opening or closing.

They usually have a delay adjustment knob on top for the timing range.

You could wire them to repeat but the automotive one is easier and cheaper to utilize.


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## jimcosta (Jun 11, 2017)

Would something like this work? Link


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## SOCOM42 (Nov 9, 2012)

jimcosta said:


> Would something like this work? Link


AH, yup, sorry I missed the link in #25.


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## SOCOM42 (Nov 9, 2012)

Just remember the flash rate will depend on how low the resistance value is.


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## SOCOM42 (Nov 9, 2012)

Hey @MountainGirl, welcome back from the catacombs!

Some are waiting to send me there, but on a cross.


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## Old SF Guy (Dec 15, 2013)

Here's an idea...

Instead of using a trip wire, since your talking about a guard pulling it, why not install a normal set of two way light switches and use a 3 wire cable to tie them all together.

https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.quora.com%2FHow-can-two-light-switch-control-one-light&psig=AOvVaw0Cu7CJMA03y68OG_g-sx4B&ust=1588212711676000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCICon8bHjOkCFQAAAAAdAAAAABAT

where you see the Neutral wire running back towards your source you can use the 3rd wire in the cable. Simply wire it to the negative terminal and you only have to run one set of wires from battery to switch 1 to switch 2 to lights.

in other words having a black, white, red set in a 3 wire cable. Connect black to switch 1 from battery then black and red from switch 1 to switch 2 and then red and white to light and at the starting end attach white to the negative terminal.

am I correct guys?

an idea.


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## Old SF Guy (Dec 15, 2013)

jimcosta said:


> One last question.
> 
> Can someone show me a relay I can order to cause the 12 VDC lights to blink on and off once the power is turned on? Thanks.


the relay at your link added to the below:
( you'd have to use a 4 wire strand I think) it would blink until someone took notice and threw a separate switch though

edited with better wiring. switch 3 (located anywhere ...as well as relay) could be labeled "alert on/off"









I'm tired forgive me if I'm mistaken.

simply using three way toggle switches that can handle the amperage would be best. for non pulsing light just use the blk/red/white as above and leave off the relay and switch 3.


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## Old SF Guy (Dec 15, 2013)

I so hate you right now.....:vs_mad:









trying to think of how to just use a different light/horn/bell to act as an alert, vice having flood lights blink. Which could allow time for folks to get away... it's friggin after midnight.....damn you man!!!!!


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## jimcosta (Jun 11, 2017)

Thanks again for all the advice gang.
With my low tech brain, attached is what I am doing.


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## Mad Trapper (Feb 12, 2014)

Old SF Guy said:


> the relay at your link added to the below:
> ( you'd have to use a 4 wire strand I think) it would blink until someone took notice and threw a separate switch though
> 
> edited with better wiring. switch 3 (located anywhere ...as well as relay) could be labeled "alert on/off"
> ...


It's just like wiring an emergency flasher/turn signal relay in a truck. If you have an old shop manual from when wiring was simple (50s-60s) use that as a guide.


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## Never_Ready_Enough (Apr 22, 2020)

Man, that's some Wile E Coyote stuff! :tango_face_smile:

I think your mates have you covered with the wiring diagrams. I would suggest adding a fuse to the situation to account for any inadvertent short-circuit happenings.

For the other items you are trying to accomplish, let me understand your scenarios:

Scenario 1:
Guard on duty simply flips on the light switch to see what's up, or address someone approaching your gate.

Scenario 2:
Things are looking dangerous.... guard pulls the emergency rip cord, which sets off a series of timed events:
1- Lights come on - they are positioned behind and above you, so as to light up the area and blind the intruders
2- Shotgun Blast to sound general alarm and scare the s**t out of the intruders
3- Tarp rolls down over the gate so the bad guys can't see through it

I think the most challenging part of this is rigging the rip cord in a way to time the events properly... I'm intrigued, as I have no experience with mechanical timed events. If anyone can share thoughts, I would appreciate.

Regards,


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## jimcosta (Jun 11, 2017)

*Never Ready Enough:*

Scenario 2:
"Things are looking dangerous.... guard pulls the emergency rip cord, which sets off a series of timed events:"
_ *Response:* That is correct._

"1- Lights come on - they are positioned behind and above you, so as to light up the area and blind the intruders"
_ *Response:* The lights are between our hidden guard shack and the gate with intruders on other side of the gate._

"2- Shotgun Blast to sound general alarm and scare the s**t out of the intruders."
_*Response:* Primary purpose of blast is to cause intruders to turn their backs to our guards so when the lights come on they are demoralized and surrender without a firefight because they do not know what force is behind them. In fact they will have to assume they are surrounded.
We then can talk after they are disarmed. At worst we will take their weapons and take them on a snipe hunt ten miles out and drop them off one at a time._

"3- Tarp rolls down over the gate so the bad guys can't see through it"
_ *Response:* Our driveway will be concealed by extending a creek fender next to it. Dirt and straw will cover the pavement. 
The long driveway on our side of the gate may be seen from the road so we will drape a camouflaged tarp on the gate giving a complete woodland scene from the road.
However the tarp may conceal intruders within ten feet of the gate so the tarp will be dropped to the ground a few seconds after the shotgun blast goes off behind the intruders._

"I think the most challenging part of this is rigging the rip cord in a way to time the events properly... I'm intrigued, as I have no experience with mechanical timed events. If anyone can share thoughts, I would appreciate."

_ *Response:* It is similar to tying three different length fuses together at one end for lighting at the same time. Each fuse goes off in a different direction and will explode at unique time based on each one's unique length._

*Final Note: * We have a second rip cord if firing begins. Our gate if 15 feet across. We got an old football tackling machine with five uprisers, 3 feet apart. We removed the paddles from each upriser. We installed a shotgun pull-string alarm on each upriser pointing out horizontally. Each shell has a 3/4" galvanized pipe over it that is an inch longer than the shell. Each shell is a number 8 birdshot.

The contraption is up against the gate on our side, hidden originally by the tarp. If the ripcord is pulled 5 shotgun blasts will cover the full width of the roadway. A false section of barb wire fence there will keep the intruders in a straight line.


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## Old SF Guy (Dec 15, 2013)

jimcosta said:


> *Never Ready Enough:*
> 
> Scenario 2:
> "Things are looking dangerous.... guard pulls the emergency rip cord, which sets off a series of timed events:"
> ...


For the mechanical spect you can use RF actuators, like they use in radio controlled aircraft. These can pull pins or activate triggers. these can be set up on the same frequency, and activated using a RF controller. I actually have two controllers and several actuators, as well as several different frequency RF transceiver units.

another way is to simply set up several Switches and instead of using RF or pull cords, use small DC motors that will wind the string and fire the devices. These could be hooked to a series of toggle switches that can wind/fire upon activation (think of the little flip up caps and toggle).

Another way to synchronies these is to us to use a Raspberry Pie computer board (about $25-$45) which can then be used to set a timing control so all happens at once. The same thing can b applies to the gate...and actuator or a DC motor to pull a pin.

Once the epidemic clears up, I'd be happy to even offer up the programming of the Raspberry Pie and/or to aid in a setup. (this is my way of getting you to divulge your location to me......LOL)


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## Never_Ready_Enough (Apr 22, 2020)

Old SF Guy said:


> For the mechanical spect you can use RF actuators, like they use in radio controlled aircraft. These can pull pins or activate triggers. these can be set up on the same frequency, and activated using a RF controller. I actually have two controllers and several actuators, as well as several different frequency RF transceiver units.
> 
> another way is to simply set up several Switches and instead of using RF or pull cords, use small DC motors that will wind the string and fire the devices. These could be hooked to a series of toggle switches that can wind/fire upon activation (think of the little flip up caps and toggle).
> 
> ...


Those are great suggestions! I need to think outside the box more.
My location is listed on my user info. Kind of a puzzle... Kind of. :tango_face_smile:


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## Never_Ready_Enough (Apr 22, 2020)

Never_Ready_Enough said:


> Those are great suggestions! I need to think outside the box more.
> My location is listed on my user info. Kind of a puzzle... Kind of. :tango_face_smile:


Sorry - I lied... I updated it. Thought I had it set but must have not took.


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## modfan (Feb 18, 2016)

#Old SF Guy
You got me thinking. Automation direct has 12v plc for about $100. Nobody would be able to hack it or cut the wires going to it and you could hook up a Keyence camera to it to detect the gate opening. There are ton of other things you can do with a good PLC. Like if you have compressed air. You could shoot Slippy pikes and not make any noise. You could hook it up to email a cell phone or cell phones with a message.


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## jimcosta (Jun 11, 2017)

*Old SF Guy*: Thanks for the offer but I have already secured all the parts needed and will be completed with this project Saturday.

I have always been impatient and just dive in so I can move on to the next project.

Dr. Phil says we all have major defining moments in our lives and I know what one of mine was.
In college I had to visit one of my accounting professors. On the back wall of his office he had a big sign which read 
*"If we all waited until we were perfect to do anything nothing would ever get done."*


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