|
??? This may be a little
off topic for this group but I need some engineering help.? I'm using some TCRT5000 Infrared
detectors (eBay).? When testing a light brown colored underframe
the detector will trip at about 1".? However when the underframe
is black that reduces to about a 1/4".? [there
is more to this story but later if required]
??? My question, if I increase the current to the
IR LED (by decreasing the resistor) can I get more range?? It
appears the resistor now is around 30mA but the device specs say
it could take 60mA.? Maybe take to 45mA!:-\
--
Jon Miller
For me time stopped in 1941
Digitrax Chief/Zephyr systems, JMRI User
SPROG User
NMRA Life member #2623
Member SFRH&MS
|
How about gluing some small bits of aluminum foil somewhere discrete?
John
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---------- Original Message ----------
From: Jon Miller <atsfus@...>
Date: August 12, 2018 at 3:10 PM
??? This may be a _little_ off topic for this group but I need some
engineering help.? I'm using some TCRT5000 Infrared detectors (eBay).?
When testing a light brown colored underframe the detector will trip at
about 1".? However when the underframe is black that reduces to about a
1/4". [there is more to this story but later if required]
??? My question, if I increase the current to the IR LED (by decreasing
the resistor) can I get more range?? It appears the resistor now is
around 30mA but the device specs say it could take 60mA.? Maybe take to
45mA!:-\
--
Jon Miller
For me time stopped in 1941
Digitrax Chief/Zephyr systems, JMRI User
SPROG User
NMRA Life member #2623
Member SFRH&MS
|
Jon,
? ? Some cars are all black underneath so they dont get detected.? Are you wanting them to look up under the track?? I use some of those IR detectors in pairs facing each other so when something comes between them I get detection.
Roger
|
I would slowly try smaller resistors.
--
Peter Ulvestad
JMRI Users Group Moderator - ( )
Tam Valley Group Moderator - ( )
Sprog-DCC Group Moderator - ( )
Edmonton Model Railroad Association -
|
On 8/12/2018 1:18 PM, John wrote:
some small bits of aluminum foil somewhere discrete
???? Hope not to do that.
--
Jon Miller
For me time stopped in 1941
Digitrax Chief/Zephyr systems, JMRI User
SPROG User
NMRA Life member #2623
Member SFRH&MS
|
That's the drawback of using IR detectors..im running into the same issue in nscale
From: Jon Miller Sent: Sunday, August 12, 2018 4:41 PM Subject: Re: [jmriusers] I/R detectors |
On 8/12/2018 1:18 PM, John wrote:
some small bits of aluminum foil somewhere discrete
???? Hope not to do that.
--
Jon Miller
For me time stopped in 1941
Digitrax Chief/Zephyr systems, JMRI User
SPROG User
NMRA Life member #2623
Member SFRH&MS
|
What about some high gloss finish on the bottom?
John
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---------- Original Message ----------
From: Scott Eric Catalano <secatalano@...>
Date: August 12, 2018 at 3:48 PM
That's the drawback of using IR detectors..im running into the same issue in
nscale
From: Jon Miller
Sent: Sunday, August 12, 2018 4:41 PM
To: [email protected]
Reply To: [email protected]
Subject: Re: [jmriusers] I/R detectors
On 8/12/2018 1:18 PM, John wrote:
some small bits of aluminum foil somewhere discrete
???? Hope not to do that.
--
Jon Miller
For me time stopped in 1941
Digitrax Chief/Zephyr systems, JMRI User
SPROG User
NMRA Life member #2623
Member SFRH&MS
|
You can increase the current up to max, or decrease the pull up on the phototransistor.
On Sun, Aug 12, 2018, 4:10 PM Jon Miller < atsfus@...> wrote:
??? This may be a little
off topic for this group but I need some engineering help.? I'm using some TCRT5000 Infrared
detectors (eBay).? When testing a light brown colored underframe
the detector will trip at about 1".? However when the underframe
is black that reduces to about a 1/4".? [there
is more to this story but later if required]
??? My question, if I increase the current to the
IR LED (by decreasing the resistor) can I get more range?? It
appears the resistor now is around 30mA but the device specs say
it could take 60mA.? Maybe take to 45mA!:-\
--
Jon Miller
For me time stopped in 1941
Digitrax Chief/Zephyr systems, JMRI User
SPROG User
NMRA Life member #2623
Member SFRH&MS
|
Jon,
?
I used the TCRT5000’s to build
across the track detectors for staging. They’re so cheap, I broke them
apart with the detector at trackside, and THREE emitters wired in series diagonally
across and above the track with 5 to 6 inches between the emitters and
detector. In series, I’ve got three times the amount of IR aimed at the
detector, with the same current level (and heat) as one emitter. Maybe it’ll
work in a reflective environment like you’re using…. FWIW…
?
Greg Komar
gkomar@...
813-453-0997
"The
nicest thing about the future is that it always starts immediately."
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Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf Of Jon Miller
Sent: Sunday, August 12, 2018 4:10
PM
To: [email protected]
Subject: [jmriusers] I/R detectors
?
???
This may be a little off topic for this group but I need some
engineering help.? I'm using some TCRT5000
Infrared detectors (eBay).? When testing a light brown colored underframe
the detector will trip at about 1".? However when the underframe is black
that reduces to about a 1/4".? [there is more
to this story but later if required]
??? My question, if I increase the
current to the IR LED (by decreasing the resistor) can I get more range??
It appears the resistor now is around 30mA but the device specs say it could
take 60mA.? Maybe take to 45mA!:-\
-- Jon Miller For me time stopped in 1941 Digitrax? Chief/Zephyr systems, JMRI User SPROG User NMRA Life member #2623 Member SFRH&MS
|
We use a lot of cheap IR emitter/detectors on our club layouts and find that they can seem a little insensitive if merely mounted looking up between the sleepers through a hole. The problem seems to be reflection from the environment around the sensor even when the train is not above the sensor. With the cheaper sensors there is a light path from emitter to detector and if mounted up through a hole there can be reflection from the sides of the hole short cutting the IR path. When the sensor sensitivity is turned up you just see more of the emitter and so the detector saturates.
We got around this problem by putting a short black tube onto the emitter and detector so the only light the detector could see was off of the trains. We used short lengths of black heatshrink about 5mm diameter (5mm led and detector) and 8mm long and we could then turn up the sensitivity so the sensor only triggered when a train went over. You can also use rubber sleeving of about 5mm or whatever diameter your lens are. The detectors seem to detect any stock that runs over them so all materials and all colours.
Dave
|
I use IR LEDs L-934F3BT . For H0 scale I use two LEDs in series with a set current of 30 mA. One phototransistor L-932P3BT.
I resolve the issue with reflection by the software.
Circuit Description
Petr
|
I use the "el cheapo" ones from eBay. I put short lengths of 1/4" heat shrink
tubing on both the emitter and receiver LEDs, I don't shrink the tubing.
These trigger a relay which cuts power to staging tracks, power is returned when
the turnout is thrown for that track.
John
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---------- Original Message ----------
From: Dave Pallant <dave@...>
Date: August 13, 2018 at 4:24 AM
We use a lot of cheap IR emitter/detectors on our club layouts and find that
they can seem a little insensitive if merely mounted looking up between the
sleepers through a hole. The problem seems to be reflection from the
environment around the sensor even when the train is not above the sensor.
With the cheaper sensors there is a light path from emitter to detector and if
mounted up through a hole there can be reflection from the sides of the hole
short cutting the IR path. When the sensor sensitivity is turned up you just
see more of the emitter and so the detector saturates.
We got around this problem by putting a short black tube onto the emitter and
detector so the only light the detector could see was off of the trains. We
used short lengths of black heatshrink about 5mm diameter (5mm led and
detector) and 8mm long and we could then turn up the sensitivity so the sensor
only triggered when a train went over. You can also use rubber sleeving of
about 5mm or whatever diameter your lens are. The detectors seem to detect any
stock that runs over them so all materials and all colours.
Dave
|
On 8/13/2018 6:00 AM, John wrote:
I use the "el cheapo" ones from eBay. I put short lengths of 1/4" heat shrink
tubing on both the emitter and receiver LEDs,
??? I didn't realize the side
reflections would be critical.? I'm going to try the tubing.?
Question or thought, would white tubing work better or worse
than black tubing.? I think white would reflect upward where
black wouldn't reflect at all.? Also would black paint work
the same?
?? Problem I have is the house
where the layout is located is away from everything so
ordering is the only choice I have.? Mail
takes time.? In a few days will be back in the bay area (CA)
so can get materials but then I'm not
near the layout for testing.:-(
--
Jon Miller
For me time stopped in 1941
Digitrax Chief/Zephyr systems, JMRI User
SPROG User
NMRA Life member #2623
Member SFRH&MS
|
On 8/12/2018 6:31 PM, Greg Komar
wrote:
I’ve got three times the amount of IR aimed at the
detector, with the same current level (and heat) as one
emitter. Maybe it’ll
work in a reflective environment like you’re using
Greg,
??? Have
some heavily cropped pictures so you can see what I'm
working with.? You might be able to see the
photo cells and IR sensors in the track.? You can also see
the IR floods I had previously installed.? The picture of
the gates was a blue wall and I painted gloss white to see
if the reflection worked better, it
didn't.
???
What's interesting is that the right IR sensor/s work just fine
and the ones for the gates don't.? Geodesic domes
can have some problems.
--
Jon Miller
For me time stopped in 1941
Digitrax Chief/Zephyr systems, JMRI User
SPROG User
NMRA Life member #2623
Member SFRH&MS
|
I used black as that was what was to hand...if you have a digital camera, you
should be able to see the IR beam, works for TV remotes too.
Don't think white is the best choice because of reflections, think about this,
why are cameras (film or digital) and their accessories black?
John
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---------- Original Message ----------
From: Jon Miller <atsfus@...>
Date: August 13, 2018 at 10:20 AM
/On 8/13/2018 6:00 AM, John wrote://
/
/I use the "el cheapo" ones from eBay. I put short lengths of 1/4" heat
shrink tubing on both the emitter and receiver LEDs,/ ??? I didn't realize the side reflections would be critical.? I'm going
to try the tubing. Question or thought, would white tubing work better
or worse than black tubing.? I think white would reflect upward where
black wouldn't reflect at all.? Also would black paint work the same?
?? Problem I have is the house where the layout is located is away from
everything so ordering is the only choice I have.? Mail takes time.? In
a few days will be back in the bay area (CA) so can get materials but
then I'm not near the layout for testing.:-(
--
Jon Miller
For me time stopped in 1941
Digitrax Chief/Zephyr systems, JMRI User
SPROG User
NMRA Life member #2623
Member SFRH&MS
|
On 8/13/2018 8:50 AM, John wrote:
Don't think white is the best choice because of reflections
??? Agree.? In the photo below
the IR
detectors? work just fine. The
wall/ceiling is at a greater angle and closer for these
detectors then the one at the gates.?
??? In the photo below the IR detectors won't work.?
??? Also note IR floods I had previously installed for another
test.? They are not on now but did turn them on once.? They
totally flood the detectors and if I change high/low outputs they
might work with just the detector part of the module. ? [this
requires testing as cars on one track may block the detectors on
the other track]
??? The glossy white paint was put on to see if above reflection
would help, it didn't.
--
Jon Miller
For me time stopped in 1941
Digitrax Chief/Zephyr systems, JMRI User
SPROG User
NMRA Life member #2623
Member SFRH&MS
|
On 8/13/2018 8:50 AM, John wrote:
Don't think white is the best choice because of reflections
??? Agree.? In the photo below
the IR
detectors? work just fine. The
wall/ceiling is at a greater angle and closer for these
detectors then the one at the gates.?
??? In the photo below the IR detectors won't work.?
??? Also note IR floods I had previously installed for another
test.? They are not on now but did turn them on once.? They
totally flood the detectors and if I change high/low outputs they
might work with just the detector part of the module. ? [this
requires testing as cars on one track may block the detectors on
the other track]
??? The glossy white paint was put on to see if above reflection
would help, it didn't.
--
Jon Miller
For me time stopped in 1941
Digitrax Chief/Zephyr systems, JMRI User
SPROG User
NMRA Life member #2623
Member SFRH&MS
|
Jon,
?
Thanks for your replies. I didn’t get the
photos you embedded in the email messages. Please post them on the group site.
?
Greg Komar
gkomar@...
"The
nicest thing about the future is that it always starts immediately."
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From: [email protected]
[mailto:[email protected]] On Behalf Of Jon Miller
Sent: Monday, August 13, 2018
12:18 PM
To: [email protected]
Subject: Re: [jmriusers] I/R
detectors
?
On 8/13/2018 8:50 AM, John wrote:
Don't think white is the best choice because of reflections
???
Agree.? In
the photo below
the
IR detectors? work just fine. The
wall/ceiling is at a greater angle and closer for these detectors then
the one at the gates.?
???
In the photo below the IR detectors won't work.?
???
Also note IR floods I had previously installed for another test.? They are
not on now but did turn them on once.? They totally flood the detectors
and if I change high/low outputs they might work with just the detector part of
the module. ? [this requires testing as cars on one track may block the
detectors on the other track]
???
The glossy white paint was put on to see if above reflection would help, it
didn't.
-- Jon Miller For me time stopped in 1941 Digitrax? Chief/Zephyr systems, JMRI User SPROG User NMRA Life member #2623 Member SFRH&MS
|
Did attachments shown up?
--
Jon Miller
For me time stopped in 1941
Digitrax Chief/Zephyr systems, JMRI User
SPROG User
NMRA Life member #2623
Member SFRH&MS
|
??? I changed the design of the detectors.? I took off the rubber
based insulation (I put on) and totally painted the "LED? package"
except for the top.? I angled the "LED package" a little.? The test
cars were a black tank car and a black bottomed box car.
??? Latter may take a picture if anyone if interested.
--
Jon Miller
For me time stopped in 1941
Digitrax Chief/Zephyr systems, JMRI User
SPROG User
NMRA Life member #2623
Member SFRH&MS
|
Roger Merritt
Peter Ulvestad
Greg Komar
Petr ?ídlo