In my experience, IR range finders have a pretty narrow field of view,
although I'm sure they vary a bit. If you were to put one in a doorframe
aimed at the other side, you'd certainly know when someone went through the
door, and that would be my pick for this project unless you need the
"tripwire" to go a long distance (say across an entire room).
As far as lasers, low-power lasers should be detectable but safe to use.
Under 5mw lasers (5mw is the limit for handhelp pointers, etc, in the US)
theoretically shouldn't do any damage to the retina before someone's blink
reflex protects them, but i'd say the lower power the better.
-Eric
On Thu, May 24, 2012 at 9:55 AM, luke browngold <victorsi...@gmail.com>wrote:
> I need to create a laser trip wire. Usually I would just do something like
> this http://www.instructables.com/id/Arduino-Laser-Tripwire/. The only
> problem is that this laser needs to be at eye level and I would prefer not
> to blind anyone. Is there anyway I can set something like this up that uses
> an invisible form of light? It seems that there are some toys that do it
> http://www.youtube.com/watch?v=7AyeyE6_v5U? Does anyone know what this
> type of laser is called?
> I also consider ultrasonic and ir range finders but the "trigger" area
> needs to be very responsive, small and focused.
> I also thought about using a PIR Motion Sensor and putting it in a
> cardboard tube to limit the trigger area. Has anyone ever tried this?
> Thanks,
> ~luke
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On Thursday, May 24, 2012 at 10:26 , Eric Skiff wrote:
> In my experience, IR range finders have a pretty narrow field of view, although I'm sure they vary a bit. If you were to put one in a doorframe aimed at the other side, you'd certainly know when someone went through the door, and that would be my pick for this project unless you need the "tripwire" to go a long distance (say across an entire room).
> As far as lasers, low-power lasers should be detectable but safe to use. Under 5mw lasers (5mw is the limit for handhelp pointers, etc, in the US) theoretically shouldn't do any damage to the retina before someone's blink reflex protects them, but i'd say the lower power the better.
> -Eric
> On Thu, May 24, 2012 at 9:55 AM, luke browngold <victorsi...@gmail.com (mailto:victorsi...@gmail.com)> wrote:
> > I need to create a laser trip wire. Usually I would just do something like this http://www.instructables.com/id/Arduino-Laser-Tripwire/. The only problem is that this laser needs to be at eye level and I would prefer not to blind anyone. Is there anyway I can set something like this up that uses an invisible form of light? It seems that there are some toys that do it http://www.youtube.com/watch?v=7AyeyE6_v5U? Does anyone know what this type of laser is called?
> > I also consider ultrasonic and ir range finders but the "trigger" area needs to be very responsive, small and focused.
> > I also thought about using a PIR Motion Sensor and putting it in a cardboard tube to limit the trigger area. Has anyone ever tried this?
> > Thanks,
> > ~luke
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I need to create a laser trip wire. Usually I would just do something like
this http://www.instructables.com/id/Arduino-Laser-Tripwire/. The only
problem is that this laser needs to be at eye level and I would prefer not
to blind anyone. Is there anyway I can set something like this up that uses
an invisible form of light? It seems that there are some toys that do it
http://www.youtube.com/watch?v=7AyeyE6_v5U? Does anyone know what this
type of laser is called?
I also consider ultrasonic and ir range finders but the "trigger" area
needs to be very responsive, small and focused.
I also thought about using a PIR Motion Sensor and putting it in a
cardboard tube to limit the trigger area. Has anyone ever tried this?
Thanks Alpay, I always assumed these ultra sonice senors had a projected
out "cone" trigger area. I will do more research. Do you have any
particular sensor you are partial too?
~luke
On Thu, May 24, 2012 at 10:46 AM, Alpay Kasal <al...@litstudios.com> wrote:
> an IR laser under 5mw is legal and safe to operate without a special
> license or protection.
> You should also be aware of this, <5mw has a good chance of getting blown
> out by ambient IR in a well lit room during daylight. If you are in an
> environment with any daylight, I'd DEFINITELY go for a ping sensor (or
> other ultrasonic) connected to a microcontroller. This will not be affected
> by lighting conditions, and acts just like a trip wire. it is a straight
> beam of inaudable sound, it reports range of distance. I have used this in
> exactly the same way before, the beam coming out of a ping is like an
> invisible strand of string through the environment. it seems to be very
> accurate too. I needed resolution in inches but i think it will show
> differences in mm.
> >but the "trigger" area needs to be very responsive, small and focused.
> On Thu, 24 May 2012 10:26:29 -0400, Eric Skiff <m...@ericskiff.com> wrote:
> In my experience, IR range finders have a pretty narrow field of view,
> although I'm sure they vary a bit. If you were to put one in a doorframe
> aimed at the other side, you'd certainly know when someone went through the
> door, and that would be my pick for this project unless you need the
> "tripwire" to go a long distance (say across an entire room).
> As far as lasers, low-power lasers should be detectable but safe to use.
> Under 5mw lasers (5mw is the limit for handhelp pointers, etc, in the US)
> theoretically shouldn't do any damage to the retina before someone's blink
> reflex protects them, but i'd say the lower power the better.
> -Eric
> On Thu, May 24, 2012 at 9:55 AM, luke browngold <victorsi...@gmail.com<http://mailto:victorsi...@gmail.com>
> > wrote:
>> I need to create a laser trip wire. Usually I would just do something
>> like this http://www.instructables.com/id/Arduino-Laser-Tripwire/. The
>> only problem is that this laser needs to be at eye level and I would prefer
>> not to blind anyone. Is there anyway I can set something like this up that
>> uses an invisible form of light? It seems that there are some toys that do
>> it http://www.youtube.com/watch?v=7AyeyE6_v5U? Does anyone know what
>> this type of laser is called?
>> I also consider ultrasonic and ir range finders but the "trigger" area
>> needs to be very responsive, small and focused.
>> I also thought about using a PIR Motion Sensor and putting it in a
>> cardboard tube to limit the trigger area. Has anyone ever tried this?
> --
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> Thanks Alpay, I always assumed these ultra sonice senors had a > projected out "cone" trigger area. I will do more research. Do you > have any particular sensor you are partial too?
> ~luke
> On Thu, May 24, 2012 at 10:46 AM, Alpay Kasal <al...@litstudios.com > <mailto:al...@litstudios.com>> wrote:
> an IR laser under 5mw is legal and safe to operate without a
> special license or protection.
> You should also be aware of this, <5mw has a good chance of
> getting blown out by ambient IR in a well lit room during
> daylight. If you are in an environment with any daylight, I'd
> DEFINITELY go for a ping sensor (or other ultrasonic) connected to
> a microcontroller. This will not be affected by lighting
> conditions, and acts just like a trip wire. it is a straight beam
> of inaudable sound, it reports range of distance. I have used this
> in exactly the same way before, the beam coming out of a ping is
> like an invisible strand of string through the environment. it
> seems to be very accurate too. I needed resolution in inches but i
> think it will show differences in mm.
> >but the "trigger" area needs to be very responsive, small and
> focused.
> On Thu, 24 May 2012 10:26:29 -0400, Eric Skiff <m...@ericskiff.com
> <mailto:m...@ericskiff.com>> wrote:
> In my experience, IR range finders have a pretty narrow field
> of view, although I'm sure they vary a bit. If you were to put
> one in a doorframe aimed at the other side, you'd certainly
> know when someone went through the door, and that would be my
> pick for this project unless you need the "tripwire" to go a
> long distance (say across an entire room).
> As far as lasers, low-power lasers should be detectable but
> safe to use. Under 5mw lasers (5mw is the limit for handhelp
> pointers, etc, in the US) theoretically shouldn't do any
> damage to the retina before someone's blink reflex protects
> them, but i'd say the lower power the better.
> -Eric
> On Thu, May 24, 2012 at 9:55 AM, luke browngold
> <victorsi...@gmail.com <http://mailto:victorsi...@gmail.com>>
> wrote:
> I need to create a laser trip wire. Usually I would just
> do something like this
> http://www.instructables.com/id/Arduino-Laser-Tripwire/.
> The only problem is that this laser needs to be at eye
> level and I would prefer not to blind anyone. Is there
> anyway I can set something like this up that uses an
> invisible form of light? It seems that there are some toys
> that do it http://www.youtube.com/watch?v=7AyeyE6_v5U? > Does anyone know what this type of laser is called?
> I also consider ultrasonic and ir range finders but the
> "trigger" area needs to be very responsive, small and focused.
> I also thought about using a PIR Motion Sensor and putting
> it in a cardboard tube to limit the trigger area. Has
> anyone ever tried this?
> -- > You received this message because you are subscribed to the
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> <mailto:nycresistormicrocontrollers@googlegroups.com>.
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On Thu, 24 May 2012 11:37:02 -0400, luke browngold wrote:
Thanks Alpay, I always assumed these ultra sonice senors had a projected out "cone" trigger area. I will do more research. Do you have any particular sensor you are partial too?
~luke
On Thu, May 24, 2012 at 10:46 AM, Alpay Kasal wrote:
an IR laser under 5mw is legal and safe to operate without a special license or protection.
