User laser pointer for break-beam motion detection

[SumGuy]

I'm not into laser-pointers but I do want to make something that might involve using a laser pointer so I thought I'd ask here.

I want to point what I guess should be a focused beam of light, probably IR, at a fixed reflector, which would bounce the light back to the transmitter where it would hit a receiver. These are typically called retro-reflective beam break or photoelectric beam detectors.

The distance I'm looking at is about 150 feet. I guess there aren't a lot of infra-red laser pointers, but maybe if someone has already tried this with a red laser pointer then it would be similar to what I'm looking for. I see there's a website called civillaser .com and they have 10 to 250 mw IR laser modules for $30 - $60 but I'm not sure what to use as a detector.

So has anyone ever tried to make a beam-break detector using a laser pointer, and what sort of range did you get, and what was your power?

 

[Alaskan]

I've seen commercial break beam motion detection using a simple light source, I presume modulated, possibly IR, but not in the visual light spectrum. I googled this subject, there is an abundance of info on the net.

 

[CurtisOliver]

I do remember a guide I saw once for making one with a raspberry pi. As Alaskan said, there is a huge abundance on this on the internet already. In fact you may even be able to buy yourself a diy kit.
The only limitation I can see with your project is the distance. 150ft is a long distance for a laser trip wire. Also you don't need excessive power, you just need a low diverging source.

 

[lasersbee]

From your question I assume you have limited Electronic
Assembly/Design knowledge.

Depending on the location of this retro-reflective Beam
Break detector this may be problematic.
1) Ground vibrations on the laser over a distance of 300'
can move the beam off target.
2) Ambient light washout (requires a modulated beam)
3) Depending on height over ground...Insects, birds and
other animals breaking the beam.
4) If outside rain, snow, dust etc breaking the beam

With the proper Electronic Design and knowledge it is
doable.


Jerry

 

[paul1598419]

As Curtis mentioned, you will need a low diverging laser source for 150 feet of trip alarm. IR is usually considered a higher diverging beam so you might find something in the visible spectrum more useful. It needn't be of high power and so wouldn't be seen by persons who you are trying to protect yourself from. Modulated beams would be far more difficult to overcome as an alarm system.

 

[Encap]

I'm not into laser-pointers but I do want to make something that might involve using a laser pointer so I thought I'd ask here.

I want to point what I guess should be a focused beam of light, probably IR, at a fixed reflector, which would bounce the light back to the transmitter where it would hit a receiver. These are typically called retro-reflective beam break or photoelectric beam detectors.

The distance I'm looking at is about 150 feet. I guess there aren't a lot of infra-red laser pointers, but maybe if someone has already tried this with a red laser pointer then it would be similar to what I'm looking for. I see there's a website called civillaser .com and they have 10 to 250 mw IR laser modules for $30 - $60 but I'm not sure what to use as a detector.

So has anyone ever tried to make a beam-break detector using a laser pointer, and what sort of range did you get, and what was your power?

Are you looking for a handheld to defeat or circumvent an IR beam beam break sensor or are you looking for a to aquire and set up a beam break motion dection system?

If you need a system here is one with 3 beams good to 2500 feet --no pain, low cost solution--- https://www.amazon.com/Dakota-Alert-BBT-2500-Break-Transmitter/dp/B0083OASEI/ref=pd_sim_421_3?_encoding=UTF8&pd_rd_i=B0083OASEI&pd_rd_r=ESFNSQ1S5WXXGESAFMFD&pd_rd_w=hJ9iZ&pd_rd_wg=EaKQs&psc=1&refRID=ESFNSQ1S5WXXGESAFMFD

 

[SumGuy]

> Are you looking for a handheld to defeat or circumvent an IR beam beam break sensor

I have no idea where you get that from my initial post, but no, this is not about defeating a beam-break sensor.

> or are you looking for a to aquire and set up a beam break motion dection system?

I am looking to aquire or make one. I have quite a bit of analog and digital electronics experience, but there are many components and modules and designs out there and I could be putzing around for quite a while buying stuff on digikey before I hit upon something that works.

> If you need a system here is one with 3 beams good to 2500 feet --no pain, low cost solution-

I can only put a reflector at the second (distant) point of the path to be covered by the beam - not something like a "gizmo" that would need a power supply (and would itself be a target for theft or vandalism). Even a hooded reflector might be too visually apparent, but it could be done.

(and btw, the Dakota product has a detection range of 300 feet - the 2500 feet is the range that it can transmit a radio break-beam signal to a base station)

 

[Encap]

> Are you looking for a handheld to defeat or circumvent an IR beam beam break sensor

I have no idea where you get that from my initial post, but no, this is not about defeating a beam-break sensor.

I am looking to aquire or make one. I have quite a bit of analog and digital electronics experience, but there are many components and modules and designs out there and I could be putzing around for quite a while buying stuff on digikey before I hit upon something that works.

I can only put a reflector at the second (distant) point of the path to be covered by the beam - not something like a "gizmo" that would need a power supply (and would itself be a target for theft or vandalism). Even a hooded reflector might be too visually apparent, but it could be done.

(and btw, the Dakota product has a detection range of 300 feet - the 2500 feet is the range that it can transmit a radio break-beam signal to a base station)

I got tthat idea from your mentioning "something that might involve using a laser pointer" - pointers discussed here are hand held, have a limited run time/ duty cycle due to heat generated and/or battery life.

You are probably better off wtih one of the many manufactured sytems that works than building one that might not work as well and cost more .

THe dakota is just one of many but would fit you 150 ft requirement and need no power supply as it captures what it needs from solar.
"The sensor is a solar powered wireless infrared break beam sensor that is simple to install and requires no wiring. The break beam sensors are powered by lithium ion batteries that are recharged through the solar panels during the day. The infrared sensing terminals can be mounted up to 300 feet apart and send a signal back to the receiver up to half mile away anytime someone passes between the sensors"

If you don't like that one there are many other makes and types--just trying to point out the obvious that people don't usually try to reinvent what is available already, works well and available at at low cost.

Anyway good luck in buliding one that is a better fit than what is available , for your application

 

[Benm]

You don't really need much power to cover that distance, it's just a matter of modulation so you can tell singal from the laser apart from ambient light.

I suppose one of the easiest ways to go about this is to actually use IR remote control technology, transmitting a specific code continously from the laser, and using a remote control sensor as the detector. This things usually operate at 35-40 kHz, and the receivers have filtering built in.

To get better security you could run through a long sequence of (pseudorandom) codes making it impossible for anyone to cross the beam using their own laser pointed at the detector.

Even using a single code will work though, if you keep transmitting the IR command for 'volume down' in RC5 and look for that in the receiver it would be hard to circumvent with a simple laser pointer.

This would be better than most commercial systems that ring a bell if someone passes through a door or something since those have no encoding at all.

 

[SumGuy]

I'm not interested at all in coding the beam for security. This beam would be used (turned on and monitored) between the evening hours of, say, midnight to 5 or 6 am (so almost no ambient light). The intent is to detect a person or people walking down the far end of the court I live on as they likely intend on checking for unlocked cars or stealing security cameras they see mounted to the eves of houses above their driveways. The beam path I have in mind would start at my house, hit a reflector on a lamp post 150 feet up the road, and be reflected back. This path would cover a section of the road that, if crossed, would give me enough time to get up, go to my window, and observe what-ever it is that triggered the beam. The beam-break signal could also be used to start night-cam recording, etc. And yes, a car or some other vehicle could or would trigger the beam-break, but I'd deal with that later some how (or not). I would love to have a gizmo that would be scanning for cell phone IEMI/IMSI data (or wifi/bluetooth MAC address) because everyone including miscreants carry phones all the time - so a more reliable "person detector" would simply be a cell-phone detector. But other than making an IMSI catcher there aren't any off-the-shelf solutions for that. Once such a system "learns" which cell phones are normal for the area, the detection of a new phone entering the area, specifically at that time of day, would be very diagnostic for a thief.

 

[paul1598419]

I don't know what country you are in, but in the USA that would be a real problem for you. You can't have a laser system or likely any system that isn't on your own property. I guess your intentions are "good", but that doesn't make it legal to do.

 

[Alaskan]

Use a low power single mode IR laser diode pulsed at a specific repetition rate to keep from false readings, should work fine in the daylight hours or night and be undetectable by the naked eye. . Search under Arduino IR Breakbeam Sensors. There is plenty of information on the net and other forums where individuals have threads on this subject, this is more of a laser pointer forum. My suggestion is this; if you have questions about lasers ask away, but a break beam system, google it and go to Arduino forums.

Maybe a member can help, so far we don't seem to be helping much. You can buy IR break beam alarms off the shelf, wouldn't that be a better option for a security system?

 

[lasersbee]

Like others have said... why not get something
off the shelf...
You could even use something like this with the
Transmitter and sensor at the same location and
a reflector at a distance. These are rated at 100m
or 328 feet which would be the round trip distance.

1pair 100m Dual Beam IR Infrared Detector Module Burglar Alarm CA NEW | eBay


Jerry

 

[SumGuy]

> You can buy IR break beam alarms off the shelf, wouldn't that be a better option for a security system?
> Like others have said... why not get something off the shelf...
> These are rated at 100m or 328 feet which would be the round trip distance

Again, what is being suggested is *not* a system based on a reflector at the opposite end of the detection path. I've already said that I don't want to put a "gizmo" on the far end of the path (in this case, a street-light pole) because it would attract too much attention / curiosity and probably not be there for too long. I haven't seen a reflector-based off-the-shelf system with specs for the distance I'm looking at (150 ft).

 

[Encap]

I don't know what country you are in, but in the USA that would be a real problem for you. You can't have a laser system or likely any system that isn't on your own property. I guess your intentions are "good", but that doesn't make it legal to do.

Exactly and true. Is a bit over the edge away from rational.

>
Again, what is being suggested is *not* a system based on a reflector at the opposite end of the detection path. I've already said that I don't want to put a "gizmo" on the far end of the path (in this case, a street-light pole) because it would attract too much attention / curiosity and probably not be there for too long. I haven't seen a reflector-based off-the-shelf system with specs for the distance I'm looking at (150 ft).

Whatever your problems are and why they are not going to be resolved here as no security related equipment that exists for your level of concerned watchfulness because there no need in the real world for it real reasons or it is legally prohibited apparently.

Good luck cracking the mysterious and dangerous walking down the court stealing all but worthless security cameras they see mounted to the eves of houses above their driveways that could more easily be stolen from WalMart thief ring and the pesky not from here/your block or on your property but in the area cell phone owners/users menace.