Light interface
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My 14 year old has been learning stamps and is excited to try a
project where the front garden lights turn on as someone approaches
the walkway. He has ideas to program the stamp so that each of the
12v garden lights turns on in order, slowly getting brighter, each
light staying on for 15 seconds or so, then dimming again.
He already has infrared sensors from previous projects, and plans to
put one at each end of the sidewalk. As each end is activated the
lights would turn on in order starting with the closest light to the
activated sensor.. if that makes sense.
I have seen interface boards that make the control of higher currents
like this easy.. but I am having a hard time finding them again. Here
is one..
http://www.geocities.com/jimforkin2003/
Ideally I would find one a bit cheaper..but that may not be possible.
I found one some time ago designed for robots that looked pretty
sweet.. but..
I want him to do the programming on his own, and he seems to be coming
up with interesting ideas and understand sub routines and all that.
He knows more about this than I do. But I think a simple board to
plug the stamp into would be nice.
Any thoughts?
Thanks in advance.
Bryan
Seattle
project where the front garden lights turn on as someone approaches
the walkway. He has ideas to program the stamp so that each of the
12v garden lights turns on in order, slowly getting brighter, each
light staying on for 15 seconds or so, then dimming again.
He already has infrared sensors from previous projects, and plans to
put one at each end of the sidewalk. As each end is activated the
lights would turn on in order starting with the closest light to the
activated sensor.. if that makes sense.
I have seen interface boards that make the control of higher currents
like this easy.. but I am having a hard time finding them again. Here
is one..
http://www.geocities.com/jimforkin2003/
Ideally I would find one a bit cheaper..but that may not be possible.
I found one some time ago designed for robots that looked pretty
sweet.. but..
I want him to do the programming on his own, and he seems to be coming
up with interesting ideas and understand sub routines and all that.
He knows more about this than I do. But I think a simple board to
plug the stamp into would be nice.
Any thoughts?
Thanks in advance.
Bryan
Seattle
Comments
kingfm@y... writes:
My 14 year old has been learning stamps and is excited to try a
project where the front garden lights turn on as someone approaches
the walkway. He has ideas to program the stamp so that each of the
12v garden lights turns on in order, slowly getting brighter, each
light staying on for 15 seconds or so, then dimming again.
He already has infrared sensors from previous projects, and plans to
put one at each end of the sidewalk. As each end is activated the
lights would turn on in order starting with the closest light to the
activated sensor.. if that makes sense.
I have seen interface boards that make the control of higher currents
like this easy.. but I am having a hard time finding them again. Here
is one..
http://www.geocities.com/jimforkin2003/
Ideally I would find one a bit cheaper..but that may not be possible.
I found one some time ago designed for robots that looked pretty
sweet.. but..
I want him to do the programming on his own, and he seems to be coming
up with interesting ideas and understand sub routines and all that.
He knows more about this than I do. But I think a simple board to
plug the stamp into would be nice.
Any thoughts?
Thanks in advance.
Bryan
Seattle
Hello Bryan,
I think it's great your 14 yo is programming. Regarding the control of 12
volt lamps, how about you and your son take the next step, and make the lamp
driver / stamp interface yourself. It is not that hard, and this group
(including
myself off list) can give you plenty of support. Also, there are
"programmers" and "hardware guys" and those that can do both have a leg up!!
The first question to recommend either a home built interface or puchasing a
prebuilt interface is to know how much current each lamp will take, and how do
you plan to control the brightness (pwm)?
[noparse][[/noparse]Non-text portions of this message have been removed]
of 12
> volt lamps, how about you and your son take the next step, and make
the lamp
> driver / stamp interface yourself. It is not that hard, and this
group (including
> myself off list) can give you plenty of support. Also, there are
> "programmers" and "hardware guys" and those that can do both have a
leg up!!
>
> The first question to recommend either a home built interface or
puchasing a
> prebuilt interface is to know how much current each lamp will take,
and how do
> you plan to control the brightness (pwm)?
Thanks for the help. Maybe I should really take this all the way and
let my son talk with anyone in the group who wants to help. Get myself
out of the loop for now. I am a big believer in having my son get as
much diversity of experience as he can. A broad knowledge base is
good for you.. and fun. (And he has some genetic issues, 11
operations and the like that make life a bit more of a challenge as
well, so this becomes even more important!)
We did talk PWM, and I found a page that had some code on that.
Today we sat outside and tried to think of all the subroutines we
could, so he could break this project down into a series of manageable
projects.
sleep mode (where small scale light show happens, though it must check
often for infra red detection)
infra-red detection
Active lighting with detection from street side of sidewalk
Active lighting detection from house side
photocell system On at dusk, off at sunrise.
sub-sub routines
Lamp dim (probably pwm)
Lamp bright
tone that alerts us inside that someone is coming, but not when
someone leaves or during sleep mode.
He has worked his way through three of the Parallax books, but got a
little slap dash on the last one. But I have made done even fewer
programs than my son has... so this is all a mildly educated guess!
But anyway... I will see if my son, Alex, can take over.
> My 14 year old has been learning stamps and is excited to try a
> project where the front garden lights turn on as someone approaches
> the walkway. He has ideas to program the stamp so that each of the
> 12v garden lights turns on in order, slowly getting brighter, each
> light staying on for 15 seconds or so, then dimming again.
>
> He already has infrared sensors from previous projects, and plans
to
> put one at each end of the sidewalk. As each end is activated the
> lights would turn on in order starting with the closest light to
the
> activated sensor.. if that makes sense.
>
> I have seen interface boards that make the control of higher
currents
> like this easy.. but I am having a hard time finding them again.
Here
> is one..
>
> http://www.geocities.com/jimforkin2003/
>
> Ideally I would find one a bit cheaper..but that may not be
possible.
> I found one some time ago designed for robots that looked pretty
> sweet.. but..
>
> I want him to do the programming on his own, and he seems to be
coming
> up with interesting ideas and understand sub routines and all
that.
> He knows more about this than I do. But I think a simple board to
> plug the stamp into would be nice.
>
> Any thoughts?
>
> Thanks in advance.
>
> Bryan
> Seattle
It may be time to design your own.
a MOSFET could handle the load, and it can be pulsed. I think we
recently discussed pulsing faster than 40hz will be un-noticable to
the human eye. changing the duty cycle or the frequency of pulses
will allow dimming with just digital outputs.
Dave
kingfm@y... writes:
Today we sat outside and tried to think of all the subroutines we
could, so he could break this project down into a series of manageable
projects.
That is a good approach........generally, a good programming technique is to
try to break up the project into small sections, hence, sub-routines.
Myself and many others in this group are glad to help.
Ken
[noparse][[/noparse]Non-text portions of this message have been removed]
of his light interface. It is designed to turn on the 12v lights
along the garden path when it detects someone. So far it works on
the desktop... just sensing us and turning on LEDs. But, we used
infra-red emitters and detectors. If you break the beam the lights
turn on in order. However, these have a very short range and
appear pretty spotty. Any ideas as to how he can sense motion and
trigger the input? he has one at each end of the sidewalk. Ideally
it would not be expensive! Ideally weatherproof.. or able to sit
inside a weatherproof tuperware container or some such.. and still
work. A motion detector from a burgler alarm would work, triggering
a relay or some such. Or?
7 or 8 feet:
http://www.junun.org/MarkIII/Info.jsp?item=17
but it's analog and you'll have to use a separate ADC. They make a
digital one that's fairly long range, 80cm:
http://www.junun.org/MarkIII/Info.jsp?item=25
might be a better choice.
I have some of the analog ones and the front lenses "appear" to be
sealed, but I can't claim if they're waterproof. But you can seal any
holes in your container where wires or anything exits with automotive
RTV silicone, just make sure to use the kind that says it's sensor
safe, as some variety are corrosive to electronics. Best regards,
-Dave
--- In basicstamps@yahoogroups.com, "surbahars" <kingfm@y...> wrote:
> So my son has made great progress and has finished the first stage
> of his light interface. It is designed to turn on the 12v lights
> along the garden path when it detects someone. So far it works on
> the desktop... just sensing us and turning on LEDs. But, we used
> infra-red emitters and detectors. If you break the beam the lights
> turn on in order. However, these have a very short range and
> appear pretty spotty. Any ideas as to how he can sense motion and
> trigger the input? he has one at each end of the sidewalk.
Ideally
> it would not be expensive! Ideally weatherproof.. or able to sit
> inside a weatherproof tuperware container or some such.. and still
> work. A motion detector from a burgler alarm would work,
triggering
> a relay or some such. Or?
>of his light interface. It is designed to turn on the 12v lights
>along the garden path when it detects someone. So far it works on
>the desktop... just sensing us and turning on LEDs. But, we used
>infra-red emitters and detectors. If you break the beam the lights
>turn on in order. However, these have a very short range and
>appear pretty spotty. Any ideas as to how he can sense motion and
>trigger the input? he has one at each end of the sidewalk. Ideally
>it would not be expensive! Ideally weatherproof.. or able to sit
>inside a weatherproof tuperware container or some such.. and still
>work. A motion detector from a burgler alarm would work, triggering
>a relay or some such. Or?
PIR (passive infrared) sensors seem like the natural choice here.
They respond to body heat in motion, and the range can easily reach
10s of feet, with a lens in front of the detector.
http://www.MPJA.com has been advertising both modules (7860-KT and
12842-SC) and bare sensors (7250-MI).
-- Tracy
know if there are PIR units which detect a smaller angle ? 120/138 degrees
is pretty large.
On Sun, 16 Nov 2003, Tracy Allen wrote:
> >So my son has made great progress and has finished the first stage
> >of his light interface. It is designed to turn on the 12v lights
> >along the garden path when it detects someone. So far it works on
> >the desktop... just sensing us and turning on LEDs. But, we used
> >infra-red emitters and detectors. If you break the beam the lights
> >turn on in order. However, these have a very short range and
> >appear pretty spotty. Any ideas as to how he can sense motion and
> >trigger the input? he has one at each end of the sidewalk. Ideally
> >it would not be expensive! Ideally weatherproof.. or able to sit
> >inside a weatherproof tuperware container or some such.. and still
> >work. A motion detector from a burgler alarm would work, triggering
> >a relay or some such. Or?
>
> PIR (passive infrared) sensors seem like the natural choice here.
> They respond to body heat in motion, and the range can easily reach
> 10s of feet, with a lens in front of the detector.
> http://www.MPJA.com has been advertising both modules (7860-KT and
> 12842-SC) and bare sensors (7250-MI).
>
> -- Tracy
>
>
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Sean T. Lamont, CTO / Chief NetNerd, Abstract Software, Inc. (ServNet)
Seattle - Bellingham - Vancouver - Portland - Everett - Tacoma - Bremerton
email: lamont@a... WWW: http://www.serv.net
"Do not fear mistakes, There Are None" - Miles Davis
>This is an interesting product for something I was going to do, but do you
>know if there are PIR units which detect a smaller angle ? 120/138 degrees
>is pretty large.
Look for the PIR sensors that ignore pets. They have a smaller "window".
Bruce
plastic lenses for IR body detection. That includes arrays of the
sort you often see on security systems. Those have curtain or
multimode angular vision, many patterns offered. The company also
has plain fresnel lenses that cover pretty much a narrow cone.
We purchased from them a few years back, 4 inch diameter circular
lenses made with polyIR-2 material, with a focal length of about 2.8
inches. For looking out over a long narrow opening where bats were
going in and out. To use those lenses you either have to start from
scratch with a PIR detector element and an amplifier, or you have to
hack a module to use the lens you want.
-- Tracy
>This is an interesting product for something I was going to do, but do you
>know if there are PIR units which detect a smaller angle ? 120/138 degrees
>is pretty large.
>
>On Sun, 16 Nov 2003, Tracy Allen wrote:
>
>> >So my son has made great progress and has finished the first stage
>> >of his light interface. It is designed to turn on the 12v lights
>> >along the garden path when it detects someone. So far it works on
>> >the desktop... just sensing us and turning on LEDs. But, we used
>> >infra-red emitters and detectors. If you break the beam the lights
>> >turn on in order. However, these have a very short range and
>> >appear pretty spotty. Any ideas as to how he can sense motion and
>> >trigger the input? he has one at each end of the sidewalk. Ideally
>> >it would not be expensive! Ideally weatherproof.. or able to sit
>> >inside a weatherproof tuperware container or some such.. and still
>> >work. A motion detector from a burgler alarm would work, triggering
>> >a relay or some such. Or?
>>
>> PIR (passive infrared) sensors seem like the natural choice here.
>> They respond to body heat in motion, and the range can easily reach
>> 10s of feet, with a lens in front of the detector.
>> http://www.MPJA.com has been advertising both modules (7860-KT and
>> 12842-SC) and bare sensors (7250-MI).
>>
>
> > -- Tracy
>Sean T. Lamont, CTO / Chief NetNerd, Abstract Software, Inc. (ServNet)
>Seattle - Bellingham - Vancouver - Portland - Everett - Tacoma - Bremerton
>email: lamont@a... WWW: http://www.serv.net
> "Do not fear mistakes, There Are None" - Miles Davis
find some very useful information on hacking some very common
PIR motion activated lights that can be bought at Walmart for
about $7.
When the hack (which is quite simple) is completed you have a
PIR detector that can be easily interfaced to to the stamp. The
original intent was for building "game cameras" but it's very
useful for all kinds of stamp projects as well.
Michael