# Homey's Super simple Break Beamer



## HomeyDaClown (Oct 3, 2009)

I was playing with a bag of old photocell lamp controls and came up with this idea. A break beam setup that requires no special wiring or soldering and works great. Just supply an extension cord for power and plug the device, lamp or Wall wart into the end for whatever you want to power up or activate when the beam is broken.


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## stagehand1975 (Feb 22, 2010)

That is close to how they used to be made long ago. A beam generated by an incandesent light bounced of a reflector back to the sensor.


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## BIGANT (Jul 13, 2010)

stagehand1975 said:


> That is close to how they used to be made long ago. A beam generated by an incandesent light bounced of a reflector back to the sensor.


our old garage door sensors worked exactly that way!


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## CoolDJTV (Jun 28, 2011)

amazeing! Great idea! I'm going to build 5 of em!


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## niblique71 (Dec 2, 2009)

Well Homey, You did it again. Fabulous Idea and Simple as can be. You Da CLOWN!!


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## ouizul1 (May 22, 2010)

Excellent! I've been toying around with the Velleman IR kit and while it works fine, I just can't get the range out of it I need. 

All I need it to do is trip a relay, this looks like it will fit the bill...can't wait to try it out.

...thanks.


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## HomeyDaClown (Oct 3, 2009)

ouizul1 said:


> Excellent! I've been toying around with the Velleman IR kit and while it works fine, I just can't get the range out of it I need.
> 
> All I need it to do is trip a relay, this looks like it will fit the bill...can't wait to try it out.
> 
> ...thanks.


Glad it helps

Yep, I've used IR beams before and they work fine across doorways and such but are hard to aim and get good distance. I have a bunch of IRs on my son's model train layout to trigger stuff. The laser can be quite a distance away. I tested in my shop at about 30 ft. using a cheapo flexible camera tripod.


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## hedg12 (Jul 6, 2008)

Very cool! 
Do you have any trouble with the laser diode overheating from continuous use? I know they're low powered, but you never know...


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## Jaybo (Mar 2, 2009)

You could also do this with a small flashlight hid inside of a PVC pipe. The pipe would narrow the beam of the flashlight, so as long as it was kept low to the ground it would not be seen.


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## HomeyDaClown (Oct 3, 2009)

I've now used three different cheapo laser pointers from the dollar store, two reds and a green. I've had them running for hours and no heat problems, I think most of these are pretty low power and the optics are not very good which is an advantage. The more distance you have, the wider the beam becomes making it easier to aim. 

I carefully gutted the pointers to take out the laser modules in order to power them from wall warts. Common 4.5 to 5 volt wall warts for either usb or cell phones work fine after adding a diode or 2 in series to drop the voltage a little.

I tried a small led flashlight but I was looking to hide the beam as much as possible. By placing a small tube over the photocell you can hide where the beam hits. I plan on keeping the beam path about 2 feet off the ground with about 15 to 20 ft in between.  That way no one will notice. By the time their legs break the beam, their attention will be on the activated prop.


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## Lunatic (Oct 3, 2006)

Nice. Thanks!


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## redg8r (Oct 20, 2007)

Brilliant.....

Any specs on the delay or duration of on/off time?



HomeyDaClown said:


> I carefully gutted the pointers to take out the laser modules in order to power them from wall warts. Common 4.5 to 5 volt wall warts for either usb or cell phones work fine after adding a diode or 2 in series to drop the voltage a little.


Any pics or schematics?
I'm needy...lol, just sayin.....

Seriously though, thanks for contributing.


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## HomeyDaClown (Oct 3, 2009)

No delay at all, it's a simple break beam, break the beam and it's on. You could always add a time delay relay but then it's not simple anymore.










Any common 1 amp Diodes should work, Like the 1N4001 type.​​


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## ouizul1 (May 22, 2010)

I'm curious as to why you chose to use diodes instead of resistors to drop the voltage.


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## hedg12 (Jul 6, 2008)

Resistors would reduce the current through the circuit, not the voltage.


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## redg8r (Oct 20, 2007)

HomeyDaClown said:


> No delay at all....​




Sorry, guess I shoulda been more specific, I meant how long is the circuit completed after breaking the beam, or does the socket switch back off as soon as the beam is unbroken?

Thanks for the diagram.​


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## corey872 (Jan 10, 2010)

Earlier you said you had red and green lasers from the dollar store? Do you have any part numbers, names, manufacturer, etc? Would like to pick up some green ones if they are that cheap!


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## HomeyDaClown (Oct 3, 2009)

redg8r said:


> Sorry, guess I shoulda been more specific, I meant how long is the circuit completed after breaking the beam, or does the socket switch back off as soon as the beam is unbroken?
> 
> Thanks for the diagram.


Break beam systems are mostly all simple triggers or on/off devices, so no there isn't any on time/off time. Delays or timers are normally activated (started/stopped) by the trigger.


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## HomeyDaClown (Oct 3, 2009)

corey872 said:


> Earlier you said you had red and green lasers from the dollar store? Do you have any part numbers, names, manufacturer, etc? Would like to pick up some green ones if they are that cheap!


The green one says MRO Green Laser, the reds are Ultra Brite brand both made in China. The Green was on the clearance table for $2.59 and the reds were $1 each. The Green ones always appear brighter, same with greem Leds, the human eye is more sensitive to green light.


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## ouizul1 (May 22, 2010)

All resistors have a voltage drop. It's rooted in Ohm's Law and is the basis for voltage divider networks. A single resistor can act as a current limiter, such as for LED circuits, preventing the current from exceeding a certain value. Two resistors will form a voltage divider. The voltage available between the two resistors is dependent on the source voltage and the values of the resistors. Diodes, like most semi-conductor junctions, typically only have a voltage drop of 0.7 volts.


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## hedg12 (Jul 6, 2008)

I would imagine the diodes were used for simplicity - the voltage drop is generally considered to be "constant" (its resistance is very high until the p-n junction reaches saturation, then it becomes insignificant. This generally happens at .6 - .7 volts for a normal crystalline diode and around .2 - .3 volts for a Shottky or germanium diode.) The amount of resistance needed to get the necessary voltage drop would depend on the resistance of the load - in this case the laser pointer. Without knowing that, the diodes are simply an easier way to get a "fixed" voltage drop.


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## HomeyDaClown (Oct 3, 2009)

hedg12 said:


> I would imagine the diodes were used for simplicity - the voltage drop is generally considered to be "constant" (its resistance is very high until the p-n junction reaches saturation, then it becomes insignificant. This generally happens at .6 - .7 volts for a normal crystalline diode and around .2 - .3 volts for a Shottky or germanium diode.) The amount of resistance needed to get the necessary voltage drop would depend on the resistance of the load - in this case the laser pointer. Without knowing that, the diodes are simply an easier way to get a "fixed" voltage drop.


Exactly.....simplicity is what it is all about. You can calculate a resistor value if your load is known and fixed...not something everyone wants to do.
Kinda like a fixed voltage regulator is all. The forward voltage drop of a diode is almost constant whatever the current passing through the diode. If it's a silcone diode (most common ones are) , it's a 0.7 volt drop no matter what the current draw, at least till you turn it into magic smoke, then all bet's are off. Another advantage in this case is that 1 amp diodes can dissipate up to 2 watts easily and prevents power input reversal. The bottom line is it's simple and it works.


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## ouizul1 (May 22, 2010)

Cool. Works for me, and makes sense. Especially the part about simplicity. 
It was just unusual and spawned one of the "huh?" moments. I figured there was some kind of good reason for it, otherwise it wouldn't have been bothered with. It's definitely being added to the bag of tricks.

Thanks. ...to both hedg and Homey.


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## Creep Cringle (Jun 23, 2009)

gotta love the simplicity of this one! NICE!


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## ScareRookie (Aug 1, 2008)

*Great Contribution for Home Haunters*

When I see it, I say it. This is a break through idea for home haunters. Its cheap, its simple and it works. It has open the door for many different applications to help build a home haunt, activating music, foggers, illumincation. Thank you for offer great solutions. Great example of collaboration and why this site is so great.


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## HomeyDaClown (Oct 3, 2009)

It's always good to see a crazy idea of mine get someone else going.

The things I have come up with while digging through boxes of old junk and old projects destined for the dumpster never ceases to amaze me. 

The wife just sees junk...hahaha


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