beam break detector
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Posts: 46,084
Hi List:
This is my first posting to the list. I am an occasional electronics
hobbyist (and Ham - AA4YH) from Cary, North Carolina. I bought a BS-1 a few
years ago and fooled around with it, making some LEDs blink, etc.
I now have a real project that I'm trying to design. The target
microcontroller is still undetermined, but I'm leaning toward the OOPIC (I'm
a computer scientist by profession, and like the programming paradigm of the
OOPIC).
Here's what I'd like the advice of the list on: I am designing a race timer
for timing flyball races. Flyball is a relay race for dogs - they have to
jump four hurdles, and press the pedal of a spring-loaded box, which
releases a tennis ball, then return with the tennis ball, across the four
hurdles; repeat with next dog.
I want to time the start/stop with a beam break detector. Since the dogs
that run these races can be any size, my plan is to use a total of four
beam-break detectors in the same vertical plane at four or six inch vertical
spacing. I'm thinking infrared LEDs and phototransistors. What I'd ideally
like to do is to use only one I/O line to detect whether any of the four
beams have been broken. I don't need to know which one was broken, only that
one of them was broken.
I suppose I could build something like a four-input OR circuit, but I'm
wondering if there isn't some way to create a serial chain of these
detectors, and just detect a high-to-low (or low-to-high) transition if any
beam is broken.
Does this make sense? Any thoughts? Any thoughts on my choice of
microcontroller or LED/phototransistor combination?
Thanks folks. This is a great list!
Michael Clark
This is my first posting to the list. I am an occasional electronics
hobbyist (and Ham - AA4YH) from Cary, North Carolina. I bought a BS-1 a few
years ago and fooled around with it, making some LEDs blink, etc.
I now have a real project that I'm trying to design. The target
microcontroller is still undetermined, but I'm leaning toward the OOPIC (I'm
a computer scientist by profession, and like the programming paradigm of the
OOPIC).
Here's what I'd like the advice of the list on: I am designing a race timer
for timing flyball races. Flyball is a relay race for dogs - they have to
jump four hurdles, and press the pedal of a spring-loaded box, which
releases a tennis ball, then return with the tennis ball, across the four
hurdles; repeat with next dog.
I want to time the start/stop with a beam break detector. Since the dogs
that run these races can be any size, my plan is to use a total of four
beam-break detectors in the same vertical plane at four or six inch vertical
spacing. I'm thinking infrared LEDs and phototransistors. What I'd ideally
like to do is to use only one I/O line to detect whether any of the four
beams have been broken. I don't need to know which one was broken, only that
one of them was broken.
I suppose I could build something like a four-input OR circuit, but I'm
wondering if there isn't some way to create a serial chain of these
detectors, and just detect a high-to-low (or low-to-high) transition if any
beam is broken.
Does this make sense? Any thoughts? Any thoughts on my choice of
microcontroller or LED/phototransistor combination?
Thanks folks. This is a great list!
Michael Clark
Comments
common laser pointer keychain (~650nm). It worked very well for me, but my
application did not require exact timing like you might need in a racing
application such as yours. I have not checked the delay between beam
breaking and the logic level output changing, it seems instant but it could
be slow for you.
http://home.earthlink.net/~dankgus/SCHEMATICS/photocell.bmp
--Dan
Original Message
From: "Michael Clark" <mdc@i...>
To: "Basicstamps List" <basicstamps@yahoogroups.com>
Sent: Monday, April 16, 2001 5:43 AM
Subject: [noparse][[/noparse]basicstamps] beam break detector
> Hi List:
>
> This is my first posting to the list. I am an occasional electronics
> hobbyist (and Ham - AA4YH) from Cary, North Carolina. I bought a BS-1 a
few
> years ago and fooled around with it, making some LEDs blink, etc.
>
> I now have a real project that I'm trying to design. The target
> microcontroller is still undetermined, but I'm leaning toward the OOPIC
(I'm
> a computer scientist by profession, and like the programming paradigm of
the
> OOPIC).
>
> Here's what I'd like the advice of the list on: I am designing a race
timer
> for timing flyball races. Flyball is a relay race for dogs - they have to
> jump four hurdles, and press the pedal of a spring-loaded box, which
> releases a tennis ball, then return with the tennis ball, across the four
> hurdles; repeat with next dog.
>
> I want to time the start/stop with a beam break detector. Since the dogs
> that run these races can be any size, my plan is to use a total of four
> beam-break detectors in the same vertical plane at four or six inch
vertical
> spacing. I'm thinking infrared LEDs and phototransistors. What I'd ideally
> like to do is to use only one I/O line to detect whether any of the four
> beams have been broken. I don't need to know which one was broken, only
that
> one of them was broken.
>
> I suppose I could build something like a four-input OR circuit, but I'm
> wondering if there isn't some way to create a serial chain of these
> detectors, and just detect a high-to-low (or low-to-high) transition if
any
> beam is broken.
>
> Does this make sense? Any thoughts? Any thoughts on my choice of
> microcontroller or LED/phototransistor combination?
>
> Thanks folks. This is a great list!
>
> Michael Clark
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
You might simply connect each of the four led/detector pairs through
a silicon diode, thus configuring a four input "or" that way. No TITLE chip
needed. Whenever any of the four register a "Hit" you'll get a signal,
either hi or lo, depending upon your circuit configuration. You can poll
this this point in a looping routing with the stamp and branch to a
subroutine to service this, such as a timer or whatever you like.
Hope this helps,
Russ
Original Message
From: Michael Clark <mdc@i...>
To: Basicstamps List <basicstamps@yahoogroups.com>
Sent: Monday, April 16, 2001 8:43 AM
Subject: [noparse][[/noparse]basicstamps] beam break detector
| Hi List:
|
| This is my first posting to the list. I am an occasional electronics
| hobbyist (and Ham - AA4YH) from Cary, North Carolina. I bought a BS-1 a few
| years ago and fooled around with it, making some LEDs blink, etc.
|
| I now have a real project that I'm trying to design. The target
| microcontroller is still undetermined, but I'm leaning toward the OOPIC (I'm
| a computer scientist by profession, and like the programming paradigm of the
| OOPIC).
|
| Here's what I'd like the advice of the list on: I am designing a race timer
| for timing flyball races. Flyball is a relay race for dogs - they have to
| jump four hurdles, and press the pedal of a spring-loaded box, which
| releases a tennis ball, then return with the tennis ball, across the four
| hurdles; repeat with next dog.
|
| I want to time the start/stop with a beam break detector. Since the dogs
| that run these races can be any size, my plan is to use a total of four
| beam-break detectors in the same vertical plane at four or six inch vertical
| spacing. I'm thinking infrared LEDs and phototransistors. What I'd ideally
| like to do is to use only one I/O line to detect whether any of the four
| beams have been broken. I don't need to know which one was broken, only that
| one of them was broken.
|
| I suppose I could build something like a four-input OR circuit, but I'm
| wondering if there isn't some way to create a serial chain of these
| detectors, and just detect a high-to-low (or low-to-high) transition if any
| beam is broken.
|
| Does this make sense? Any thoughts? Any thoughts on my choice of
| microcontroller or LED/phototransistor combination?
|
| Thanks folks. This is a great list!
|
| Michael Clark
|
|
|
|
| Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
|
|
what you are describing. Should I 1) connect all outputs to a single diode,
or 2) connect each output to a different diode, with diode outputs tied
together?
Original Message
From: Russ Bassani [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=L7ZJu94I1ns7Vc-i2qGPV-Lo-QyoNDVCmw47Ei90pXkmq7qaqI9rY9S5y87KGzctd_3gMk3NODRt9XUmYw]RussBassani@a...[/url
Sent: Monday, April 16, 2001 5:40 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] beam break detector
Hi Michael,
You might simply connect each of the four led/detector pairs through
a silicon diode, thus configuring a four input "or" that way. No TITLE chip
needed. Whenever any of the four register a "Hit" you'll get a signal,
either hi or lo, depending upon your circuit configuration. You can poll
this this point in a looping routing with the stamp and branch to a
subroutine to service this, such as a timer or whatever you like.
Hope this helps,
Russ
Original Message
From: Michael Clark <mdc@i...>
To: Basicstamps List <basicstamps@yahoogroups.com>
Sent: Monday, April 16, 2001 8:43 AM
Subject: [noparse][[/noparse]basicstamps] beam break detector
| Hi List:
|
| This is my first posting to the list. I am an occasional electronics
| hobbyist (and Ham - AA4YH) from Cary, North Carolina. I bought a BS-1 a
few
| years ago and fooled around with it, making some LEDs blink, etc.
|
| I now have a real project that I'm trying to design. The target
| microcontroller is still undetermined, but I'm leaning toward the OOPIC
(I'm
| a computer scientist by profession, and like the programming paradigm of
the
| OOPIC).
|
| Here's what I'd like the advice of the list on: I am designing a race
timer
| for timing flyball races. Flyball is a relay race for dogs - they have to
| jump four hurdles, and press the pedal of a spring-loaded box, which
| releases a tennis ball, then return with the tennis ball, across the four
| hurdles; repeat with next dog.
|
| I want to time the start/stop with a beam break detector. Since the dogs
| that run these races can be any size, my plan is to use a total of four
| beam-break detectors in the same vertical plane at four or six inch
vertical
| spacing. I'm thinking infrared LEDs and phototransistors. What I'd ideally
| like to do is to use only one I/O line to detect whether any of the four
| beams have been broken. I don't need to know which one was broken, only
that
| one of them was broken.
|
| I suppose I could build something like a four-input OR circuit, but I'm
| wondering if there isn't some way to create a serial chain of these
| detectors, and just detect a high-to-low (or low-to-high) transition if
any
| beam is broken.
|
| Does this make sense? Any thoughts? Any thoughts on my choice of
| microcontroller or LED/phototransistor combination?
|
| Thanks folks. This is a great list!
|
| Michael Clark
|
|
|
|
| Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
|
|
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
laser pointer as a light source, but it would certainly alleviate any
concern about distance between emitter and detector that I have.
Michael
Original Message
From: Dan Gustafson [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=z5WnN-8qUMinYNXIDlLJeBW8weMKGc1iGqO1G3uuLC0udi7jHcSYqJqm6fTi5E5Zd5Ga87LOlT80u9hVFSAc]dankgus@e...[/url
Sent: Monday, April 16, 2001 3:34 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] beam break detector
Here is a link to a schematic that will detect a break in a beam from a
common laser pointer keychain (~650nm). It worked very well for me, but my
application did not require exact timing like you might need in a racing
application such as yours. I have not checked the delay between beam
breaking and the logic level output changing, it seems instant but it could
be slow for you.
http://home.earthlink.net/~dankgus/SCHEMATICS/photocell.bmp
--Dan
Original Message
From: "Michael Clark" <mdc@i...>
To: "Basicstamps List" <basicstamps@yahoogroups.com>
Sent: Monday, April 16, 2001 5:43 AM
Subject: [noparse][[/noparse]basicstamps] beam break detector
> Hi List:
>
> This is my first posting to the list. I am an occasional electronics
> hobbyist (and Ham - AA4YH) from Cary, North Carolina. I bought a BS-1 a
few
> years ago and fooled around with it, making some LEDs blink, etc.
>
> I now have a real project that I'm trying to design. The target
> microcontroller is still undetermined, but I'm leaning toward the OOPIC
(I'm
> a computer scientist by profession, and like the programming paradigm of
the
> OOPIC).
>
> Here's what I'd like the advice of the list on: I am designing a race
timer
> for timing flyball races. Flyball is a relay race for dogs - they have to
> jump four hurdles, and press the pedal of a spring-loaded box, which
> releases a tennis ball, then return with the tennis ball, across the four
> hurdles; repeat with next dog.
>
> I want to time the start/stop with a beam break detector. Since the dogs
> that run these races can be any size, my plan is to use a total of four
> beam-break detectors in the same vertical plane at four or six inch
vertical
> spacing. I'm thinking infrared LEDs and phototransistors. What I'd ideally
> like to do is to use only one I/O line to detect whether any of the four
> beams have been broken. I don't need to know which one was broken, only
that
> one of them was broken.
>
> I suppose I could build something like a four-input OR circuit, but I'm
> wondering if there isn't some way to create a serial chain of these
> detectors, and just detect a high-to-low (or low-to-high) transition if
any
> beam is broken.
>
> Does this make sense? Any thoughts? Any thoughts on my choice of
> microcontroller or LED/phototransistor combination?
>
> Thanks folks. This is a great list!
>
> Michael Clark
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
What I meant was to use the I/R beams (4) as you described, but to
simply connect their outputs in parallel with each other, each through a
diode, so that if any of them were to register a dog "hit", that beam sensor
would pull down your signal line through its diode, to stop your counter.
The diodes would provide some isolation between the I/R sensors, since
we don't know the sensor's output configuration, and to simply connect all
four of them together might cause problems, the diodes are a way to do
it more safely.
Russ
Original Message
From: Michael Clark <mdc@i...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, April 16, 2001 7:36 PM
Subject: RE: [noparse][[/noparse]basicstamps] beam break detector
| Russ - thanks for your reply. I'm not certain that I understand exactly
| what you are describing. Should I 1) connect all outputs to a single diode,
| or 2) connect each output to a different diode, with diode outputs tied
| together?
|
|
Original Message
| From: Russ Bassani [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=3D9Rd8TbQ_3B3FfLKWmUeMq7LZX9PyEs7tDi4K0aPCDro44CIpeETSCu1lDQo-O3ZgHg3khPMT_KjjVUbu4]RussBassani@a...[/url
| Sent: Monday, April 16, 2001 5:40 PM
| To: basicstamps@yahoogroups.com
| Subject: Re: [noparse][[/noparse]basicstamps] beam break detector
|
|
| Hi Michael,
|
| You might simply connect each of the four led/detector pairs through
| a silicon diode, thus configuring a four input "or" that way. No TITLE chip
| needed. Whenever any of the four register a "Hit" you'll get a signal,
| either hi or lo, depending upon your circuit configuration. You can poll
| this this point in a looping routing with the stamp and branch to a
| subroutine to service this, such as a timer or whatever you like.
| Hope this helps,
| Russ
|
|
|
|
Original Message
| From: Michael Clark <mdc@i...>
| To: Basicstamps List <basicstamps@yahoogroups.com>
| Sent: Monday, April 16, 2001 8:43 AM
| Subject: [noparse][[/noparse]basicstamps] beam break detector
|
|
| | Hi List:
| |
| | This is my first posting to the list. I am an occasional electronics
| | hobbyist (and Ham - AA4YH) from Cary, North Carolina. I bought a BS-1 a
| few
| | years ago and fooled around with it, making some LEDs blink, etc.
| |
| | I now have a real project that I'm trying to design. The target
| | microcontroller is still undetermined, but I'm leaning toward the OOPIC
| (I'm
| | a computer scientist by profession, and like the programming paradigm of
| the
| | OOPIC).
| |
| | Here's what I'd like the advice of the list on: I am designing a race
| timer
| | for timing flyball races. Flyball is a relay race for dogs - they have to
| | jump four hurdles, and press the pedal of a spring-loaded box, which
| | releases a tennis ball, then return with the tennis ball, across the four
| | hurdles; repeat with next dog.
| |
| | I want to time the start/stop with a beam break detector. Since the dogs
| | that run these races can be any size, my plan is to use a total of four
| | beam-break detectors in the same vertical plane at four or six inch
| vertical
| | spacing. I'm thinking infrared LEDs and phototransistors. What I'd ideally
| | like to do is to use only one I/O line to detect whether any of the four
| | beams have been broken. I don't need to know which one was broken, only
| that
| | one of them was broken.
| |
| | I suppose I could build something like a four-input OR circuit, but I'm
| | wondering if there isn't some way to create a serial chain of these
| | detectors, and just detect a high-to-low (or low-to-high) transition if
| any
| | beam is broken.
| |
| | Does this make sense? Any thoughts? Any thoughts on my choice of
| | microcontroller or LED/phototransistor combination?
| |
| | Thanks folks. This is a great list!
| |
| | Michael Clark
| |
| |
| |
| |
| | Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
| |
| |
|
|
|
|
| Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
|
|
|
|
|
| Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
|
|
|