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Finding a loop detector
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Finding a loop detector
eyeyehahhaha wishful thinKing 360....try 200 pounds THUMP. FIND THE SENSITIVE AREA...I ASSUME ON THE LEAD GOING BACK TO THE SWTICH BOX.
Speak with your engineer...ak abt going to light/ultrasonic beam triggers. Look for the subject as a legal issue....tampering with those controls is deafinitly illegal. as chaos with social liability. . |
#13
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Finding a loop detector
On Mon, 14 Oct 2013 10:10:57 -0700 (PDT), Frank Krygowski
wrote: So: Anyone know the easiest way to determine the exact location of such a buried coil? The compass, stud finder, and divining rod will not work. What you need is a coil resonant to the operating frequency, some kind of detector, and an indicator. The problem is that the frequencies used vary from 10 Khz to as high as 200 Khz. That means either a broadband detector, or a tunable coil. http://en.wikipedia.org/wiki/Induction_loop If you have a smartphone of some flavor, you can probably use one of the oscilloscope apps to act as the amplifier, detector, and display. Something like this: https://play.google.com/store/apps/details?id=com.nfx.noscpro&hl=en There are also various "ghost finder" and "EMF detector" apps that are basically LF (low frequency) signal detectors. For example: https://play.google.com/store/apps/details?id=com.superphunlabs.emf&hl=en https://play.google.com/store/apps/details?id=com.codebros.emffree&hl=en They use the phones magnetic sensor as a LF pickup coil. I have no idea of the operating frequency range or sensitivity, but methinks it's worth trying. Otherwise, I would build a resonant pickup coil, setup a tuning system (switched caps and tuning capacitor), mount it on a wooden stick, and plug the coil into the microphone input. Then use an oscilloscope application to view the signal. If the signal is low, add a battery powered audio amp. If you want, I can throw something together (time permitting) and see what it produces. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#14
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Finding a loop detector
On Monday, October 14, 2013 6:59:41 PM UTC-7, Jeff Liebermann wrote:
On Mon, 14 Oct 2013 10:10:57 -0700 (PDT), Frank Krygowski wrote: So: Anyone know the easiest way to determine the exact location of such a buried coil? The compass, stud finder, and divining rod will not work. What you need is a coil resonant to the operating frequency, some kind of detector, and an indicator. The problem is that the frequencies used vary from 10 Khz to as high as 200 Khz. That means either a broadband detector, or a tunable coil. http://en.wikipedia.org/wiki/Induction_loop If you have a smartphone of some flavor, you can probably use one of the oscilloscope apps to act as the amplifier, detector, and display. Something like this: https://play.google.com/store/apps/details?id=com.nfx.noscpro&hl=en There are also various "ghost finder" and "EMF detector" apps that are basically LF (low frequency) signal detectors. For example: https://play.google.com/store/apps/details?id=com.superphunlabs.emf&hl=en https://play.google.com/store/apps/details?id=com.codebros.emffree&hl=en They use the phones magnetic sensor as a LF pickup coil. I have no idea of the operating frequency range or sensitivity, but methinks it's worth trying. Otherwise, I would build a resonant pickup coil, setup a tuning system (switched caps and tuning capacitor), mount it on a wooden stick, and plug the coil into the microphone input. Then use an oscilloscope application to view the signal. If the signal is low, add a battery powered audio amp. If you want, I can throw something together (time permitting) and see what it produces. So, is there a cell phone app for triggering the loop? -- Jay Beattie. |
#15
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Finding a loop detector
On 15/10/13 12:59, Jeff Liebermann wrote:
On Mon, 14 Oct 2013 10:10:57 -0700 (PDT), Frank Krygowski wrote: So: Anyone know the easiest way to determine the exact location of such a buried coil? The compass, stud finder, and divining rod will not work. What you need is a coil resonant to the operating frequency, some kind of detector, and an indicator. The problem is that the frequencies used vary from 10 Khz to as high as 200 Khz. That means either a broadband detector, or a tunable coil. http://en.wikipedia.org/wiki/Induction_loop If you have a smartphone of some flavor, you can probably use one of the oscilloscope apps to act as the amplifier, detector, and display. Something like this: https://play.google.com/store/apps/details?id=com.nfx.noscpro&hl=en There are also various "ghost finder" and "EMF detector" apps that are basically LF (low frequency) signal detectors. For example: https://play.google.com/store/apps/details?id=com.superphunlabs.emf&hl=en https://play.google.com/store/apps/details?id=com.codebros.emffree&hl=en They use the phones magnetic sensor as a LF pickup coil. I have no idea of the operating frequency range or sensitivity, but methinks it's worth trying. Otherwise, I would build a resonant pickup coil, setup a tuning system (switched caps and tuning capacitor), mount it on a wooden stick, and plug the coil into the microphone input. Then use an oscilloscope application to view the signal. If the signal is low, add a battery powered audio amp. If you want, I can throw something together (time permitting) and see what it produces. You will have fun listening to 200kHz signals with a microphone input circuit and A/D. Often the maximum sample rate is 192kHz for high end audio A/D converters. I don't know what phone circuits are capable of, but I'd be surprised if it was that high. -- JS |
#16
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Finding a loop detector
On Monday, October 14, 2013 7:30:26 PM UTC-7, James wrote:
On 15/10/13 12:59, Jeff Liebermann wrote: On Mon, 14 Oct 2013 10:10:57 -0700 (PDT), Frank Krygowski wrote: So: Anyone know the easiest way to determine the exact location of such a buried coil? The compass, stud finder, and divining rod will not work. What you need is a coil resonant to the operating frequency, some kind of detector, and an indicator. The problem is that the frequencies used vary from 10 Khz to as high as 200 Khz. That means either a broadband detector, or a tunable coil. http://en.wikipedia.org/wiki/Induction_loop If you have a smartphone of some flavor, you can probably use one of the oscilloscope apps to act as the amplifier, detector, and display. Something like this: https://play.google.com/store/apps/details?id=com.nfx.noscpro&hl=en There are also various "ghost finder" and "EMF detector" apps that are basically LF (low frequency) signal detectors. For example: https://play.google.com/store/apps/details?id=com.superphunlabs.emf&hl=en https://play.google.com/store/apps/details?id=com.codebros.emffree&hl=en They use the phones magnetic sensor as a LF pickup coil. I have no idea of the operating frequency range or sensitivity, but methinks it's worth trying. Otherwise, I would build a resonant pickup coil, setup a tuning system (switched caps and tuning capacitor), mount it on a wooden stick, and plug the coil into the microphone input. Then use an oscilloscope application to view the signal. If the signal is low, add a battery powered audio amp. If you want, I can throw something together (time permitting) and see what it produces. You will have fun listening to 200kHz signals with a microphone input circuit and A/D. Often the maximum sample rate is 192kHz for high end audio A/D converters. I don't know what phone circuits are capable of, but I'd be surprised if it was that high. -- JS O.K., in that case, I'll continue my practice of dragging a '69 Malibu hood behind my bike to trigger the loops. BTW, I have a friend who is convinced that you can treat a non-responsive turn signal as "broken" and may permissibly run the light. After ferreting through our version of the UVC, I found nothing to support that belief -- meaning that you can't run the light if you don't trigger the loop. I'm not clear on what you are supposed to do, however. I run the light -- but I look for cops first. -- Jay Beattie. |
#17
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Finding a loop detector
On Monday, October 14, 2013 9:59:41 PM UTC-4, Jeff Liebermann wrote:
If you want, I can throw something together (time permitting) and see what it produces. Well sure, if you like. But I'm hoping for something as simple as possible. I've posted the question on a couple other lists. Before putting any time into it, you might want to wait to see if there's a known solution out there. Thanks for the offer, though. - Frank Krygowski |
#18
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Finding a loop detector
On 15/10/13 13:43, Jay Beattie wrote:
O.K., in that case, I'll continue my practice of dragging a '69 Malibu hood behind my bike to trigger the loops. BTW, I have a friend who is convinced that you can treat a non-responsive turn signal as "broken" and may permissibly run the light. After ferreting through our version of the UVC, I found nothing to support that belief -- meaning that you can't run the light if you don't trigger the loop. I'm not clear on what you are supposed to do, however. I run the light -- but I look for cops first. I think our cops recommend you dismount and become a pedestrian. I, like you, often run the light if it doesn't sense me, when safe to do so. I have found that riding in circles over the sensor area sometimes encourages it to detect me. Just watch for cars when doing so. There are times when it is never very safe to turn due to a continual stream of traffic. I've also stopped on the sensor, not triggered it, and had a car pull up behind me that is too far back to trigger it. I then need to move forward, and encourage the driver to move forward over the sensor area. It all gets a bit of a nuisance at times. -- JS |
#19
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Finding a loop detector
Frank Krygowski writes:
On Monday, October 14, 2013 9:59:41 PM UTC-4, Jeff Liebermann wrote: If you want, I can throw something together (time permitting) and see what it produces. (Just a _tiny bit_ more context would have made a world of difference here. The subject line helps some, but seriously - look at the body of your post - no hint what you're talking about. Comically so.) Well sure, if you like. But I'm hoping for something as simple as possible. The simple solution is to assume the sensor will never detect you or your bicycle anyway, only consider the light's status as it pertains to what other people are apt to do, then proceed accordingly. I've posted the question on a couple other lists. Before putting any time into it, you might want to wait to see if there's a known solution out there. Where's the fun in that? (Unless you happen to turn up a sonic screwdriver.) Thanks for the offer, though. |
#20
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Finding a loop detector
On Mon, 14 Oct 2013 19:43:37 -0700 (PDT), Jay Beattie
wrote: On Monday, October 14, 2013 7:30:26 PM UTC-7, James wrote: On 15/10/13 12:59, Jeff Liebermann wrote: On Mon, 14 Oct 2013 10:10:57 -0700 (PDT), Frank Krygowski wrote: So: Anyone know the easiest way to determine the exact location of such a buried coil? The compass, stud finder, and divining rod will not work. What you need is a coil resonant to the operating frequency, some kind of detector, and an indicator. The problem is that the frequencies used vary from 10 Khz to as high as 200 Khz. That means either a broadband detector, or a tunable coil. http://en.wikipedia.org/wiki/Induction_loop If you have a smartphone of some flavor, you can probably use one of the oscilloscope apps to act as the amplifier, detector, and display. Something like this: https://play.google.com/store/apps/details?id=com.nfx.noscpro&hl=en There are also various "ghost finder" and "EMF detector" apps that are basically LF (low frequency) signal detectors. For example: https://play.google.com/store/apps/details?id=com.superphunlabs.emf&hl=en https://play.google.com/store/apps/details?id=com.codebros.emffree&hl=en They use the phones magnetic sensor as a LF pickup coil. I have no idea of the operating frequency range or sensitivity, but methinks it's worth trying. Otherwise, I would build a resonant pickup coil, setup a tuning system (switched caps and tuning capacitor), mount it on a wooden stick, and plug the coil into the microphone input. Then use an oscilloscope application to view the signal. If the signal is low, add a battery powered audio amp. If you want, I can throw something together (time permitting) and see what it produces. You will have fun listening to 200kHz signals with a microphone input circuit and A/D. Often the maximum sample rate is 192kHz for high end audio A/D converters. I don't know what phone circuits are capable of, but I'd be surprised if it was that high. -- JS O.K., in that case, I'll continue my practice of dragging a '69 Malibu hood behind my bike to trigger the loops. BTW, I have a friend who is convinced that you can treat a non-responsive turn signal as "broken" and may permissibly run the light. After ferreting through our version of the UVC, I found nothing to support that belief -- meaning that you can't run the light if you don't trigger the loop. I'm not clear on what you are supposed to do, however. I run the light -- but I look for cops first. -- Jay Beattie. MOST loop trigger intersections also have a "push to walk" switch. I get off the bike, walk over and punch the button, then go back and wait for the light, or "jaywalk" with the bike. |
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