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Old 05-15-24, 08:58 AM
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Originally Posted by Bald Paul
Would you like the radar to not warn of the one vehicle that is about to hit you?
It doesn’t distinguish “that one vehicle” at all.
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Old 05-15-24, 09:15 AM
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Originally Posted by FBinNY
Even if it worked great, I don't imagine there's any way to reliably predict which drivers are going to hit me from behind and which are going to swing around and pass safely (defined as no contact).
It can’t do this, obviously. (No one has made the claim it could.) So, that can’t be its purpose.

It’s more of a “don’t mosey left” warning device. You get a longer off awareness than a mirror provides. And it might be useful for people who can’t hear cars. It might be more useful when there are fewer cars.

Originally Posted by FBinNY
Secondly, there's the question of timing, Even in the best of worlds, with excellent accuracy, I don't believe, I can get warned soon enough to react effectively. So, I don't want to ride where I'm repetitively diving for shoulders, or tuning out false alarms. If I can't use info effectively, I don't need to have my peace
This is just strange. People who use (and like) them are “repetitively diving for shoulders. You have no idea how these are used.

Originally Posted by FBinNY
Ask those who live with automated warning alarms, ie. jet pilots, and they'll tell you how too many alarms is as bad, or worse, as never having alarms in the first place.
If people have an issue with this, they can turn off the alarms. It’s not the dire situation you make it out as.

Originally Posted by FBinNY
It might be age, experience, or worldview, but even for free, I'm not interested.
After trying one for a while, I find it doesn’t do much for me. Lots of people like them a lot. It’s nice they have the option even if you “not interested”.

Last edited by njkayaker; 05-15-24 at 09:47 AM.
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Old 05-15-24, 09:33 AM
  #78  
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Originally Posted by SoSmellyAir
Implementing this additional capability would require either (a) the radar to sweep back and forth and a processor to calculate the resulting differences in the Doppler shifts or (b) adding a rear facing camera and a processor to correlate the respective data stream from the radar and the camera.
This is not true.

There are “presence detectors” that use “mmWave” and track
multiple moving objects with no moving parts or cameras.
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Old 05-15-24, 09:35 AM
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Originally Posted by njkayaker

This just strange. People who use (and like) them are “repetitively diving for shoulders. You have no idea how these are used.
You're taking this too literally, and distorting it by removing the context provided by the preceding sentence. My point was that the unit wouldn't provide any actionable information (for me), since it can't distinguish between cars that are a danger to me from those that aren't.

But you are right that I have no idea how these are used by others. However, that's not something I need to care about.

Nor does the fact that I've no interest in using it, imply any judgement about other people's choices. I don't do, nor judge, what lots of people do, and do what lots of people don't, and it works out fine.

Last edited by FBinNY; 05-15-24 at 09:49 AM.
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Old 05-15-24, 09:46 AM
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Originally Posted by FBinNY
You're taking this too literally, and distorting it by removing the context provided by the preceding sentence. My point was that the unit wouldn't provide any actionable information (for me), since it can't distinguish between cars that are a danger to me from those that aren't.
They do provide useful actionable information -- just not that particular piece of information. So, yes, if that's all you care about it's clearly not for you.
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Old 05-15-24, 09:56 AM
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Depending on how you view it, the traffic alert will change the color of the screen section based on vehicle proximity.
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Old 05-15-24, 10:05 AM
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Originally Posted by FBinNY
You're taking this too literally, and distorting it by removing the context provided by the preceding sentence. My point was that the unit wouldn't provide any actionable information (for me), since it can't distinguish between cars that are a danger to me from those that aren't.
Your “actionable” was “diving into the shoulder” That’s deranged. The context doesn’t help you. No one does that.

Originally Posted by FBinNY
But you are right that I have no idea how these are used by others. However, that's not something I need to care about.
I’m not sure if co

Originally Posted by FBinNY
Nor does the fact that I've no interest in using it, imply any judgement about other people's choices. I don't do, nor judge, what lots of people do, and do what lots of people don't, and it works out fine.
The not understanding how people use them, the whole “to many alarms”, the “too much reliance on technology” (paraphrased), and the “diving onto the shoulder” nonsense all add up as kind of “judgy” and disapproving.

Last edited by njkayaker; 05-15-24 at 10:09 AM.
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Old 05-15-24, 10:11 AM
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Originally Posted by FBinNY
since it can't distinguish between cars that are a danger to me from those that aren't.

.
I think we are missing the point of the very basic function, with an assumption that ALL cars coming up behind you are a danger to you potentially and that the radar at minimum warns you that there’s a vehicle approaching. You want to know if one of those vehicles has a driver who is not paying attention and will hit you. Nothing can do that. All a radar unit can do is warn you of an approaching vehicle. Some folks use mirrors for this, I use a mirror but am on occasion not watching and miss that a car is behind me. What I desire of the radar is to fill in for when I miss what is visible in the mirror.
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Old 05-15-24, 10:37 AM
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Originally Posted by njkayaker
Your “actionable” was “diving into the shoulder” That’s deranged. The context doesn’t help you. No one does that.


I’m not sure if co


The not understanding how people use them, the whole “to many alarms”, the “too much reliance on technology” (paraphrased), and the “diving onto the shoulder” nonsense all add up as kind of “judgy” and disapproving.
I'm not going to argue. I posted why I wasn't interested in acquiring this bit of tech, and am happy to let people decide for themselves.
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Old 05-15-24, 10:57 AM
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Originally Posted by FBinNY
I'm not going to argue. I posted why I wasn't interested in acquiring this bit of tech, and am happy to let people decide for themselves.
I think people would be more receptive to your opinion if your lack of interest wasn't based on an unrealistic expectation.
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Old 05-15-24, 11:03 AM
  #86  
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Originally Posted by njkayaker
This is not true.

There are “presence detectors” that use “mmWave” and track
multiple moving objects with no moving parts or cameras.
Does the Trek CarBack have an mm wave radar? I did not know that those are already on the market. The mm wave presence detectors seem to be designed for interior space?

How does an mm Wave radar / presence detector distinguish between: (1) an object that has shifted its lateral position; (2) an object that has slightly changed its speed; (3) multiple objects, side-by-side, closing at slightly different speeds?

Last edited by SoSmellyAir; 05-15-24 at 11:19 AM.
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Old 05-15-24, 11:29 AM
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Originally Posted by SoSmellyAir
Does the Trek CarBack have an mm wave radar? I did not know that those are already on the market. The mm wave presence detectors seem to be designed for interior space?

How does an mm Wave radar / presence detector distinguish between: (1) an object that has shifted its lateral position; (2) an object that has slightly changed its speed; (3) multiple objects, side-by-side, closing at slightly different speeds?
The Trek CarBack operates at a much higher frequency than the Varia, so it “should” be more accurate, but GP Lama reports it isn’t.

Answers to questions

1. Would require more than one emitter or an array.

2. Change in the Doppler shift in the radar return.

3. Different return for each object with a different Doppler shift for each.

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Old 05-15-24, 11:32 AM
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Originally Posted by tomato coupe
I think people would be more receptive to your opinion if your lack of interest wasn't based on an unrealistic expectation.
There's no expectation, either realistic or not, here. Simply a statement that, for me, the info it offers isn't enough to cross the line from pass to buy.
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Old 05-15-24, 01:20 PM
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Originally Posted by PromptCritical
... Would require more than one emitter or an array. ...
Looking into this further, it seems that the ability to detect lateral position would require at least two emitters transmitting at different frequencies that are sufficiently far apart that they would not overlap even with Doppler shifts, right?
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Old 05-15-24, 01:43 PM
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Originally Posted by SoSmellyAir
Looking into this further, it seems that the ability to detect lateral position would require at least two emitters transmitting at different frequencies that are sufficiently far apart that they would not overlap even with Doppler shifts, right?
That would be one way to do it. The other is with a pulsed array. No idea which is cheaper, I doubt either would be affordable for consumers. Likely use a lot of power too.
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Old 05-15-24, 01:50 PM
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Originally Posted by PromptCritical
That would be one way to do it. The other is with a pulsed array. No idea which is cheaper, I doubt either would be affordable for consumers. Likely use a lot of power too.
Yeah, which brings me back to my original question: how does the Trek CarBack do it? It has an MSRP of $200, same as the Garmin Varia RTL-515 that many of us use.
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Old 05-15-24, 01:53 PM
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Originally Posted by SoSmellyAir
Yeah, which brings me back to my original question: how does the Trek CarBack do it? It has an MSRP of $200, same as the Garmin Varia RTL-515 that many of us use.
If you see the initial reviews, it doesn't do it (well).
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Old 05-15-24, 02:32 PM
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Originally Posted by howaboutme
If you see the initial reviews, it doesn't do it (well).
Yes, I see that. I am more asking / wondering about how Trek implements this feature and tests the implementation to determine / justify saying that it can detect the lateral position of an approaching vehicle.

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Old 05-15-24, 03:51 PM
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Originally Posted by SoSmellyAir
Does the Trek CarBack have an mm wave radar?
It might (not sure).

Originally Posted by SoSmellyAir
The mm wave presence detectors seem to be designed for interior space?
I only know of the interior sensors. I'm not sure why they couldn't be used outside.

Originally Posted by SoSmellyAir
How does an mm Wave radar / presence detector distinguish between: (1) an object that has shifted its lateral position; (2) an object that has slightly changed its speed; (3) multiple objects, side-by-side, closing at slightly different speeds?
Black magic, I think. Actually, it looks like they have two antennas that are separated a bit. The mmwave sensors can detect breathing. It would seem it should have no problems detecting slightly different or changing speeds. The indoor sensors can track a limited number of objects (like 3).
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Old 05-15-24, 03:55 PM
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Originally Posted by FBinNY
Originally Posted by FBinNY
It might be age, experience, or worldview, but even for free, I'm not interested.
I'm not going to argue. I posted why I wasn't interested in acquiring this bit of tech, and am happy to let people decide for themselves.
Why would anybody care?

Your "whys" were kind of dismissive too.

Originally Posted by FBinNY
But you are right that I have no idea how these are used by others. However, that's not something I need to care about.
So, it's something you don't know much about and don't care to learn anything about. Is telling people you are "not interested" in it at all useful to them? (Hint: no, it's not useful at all.)

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Old 05-15-24, 03:58 PM
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Originally Posted by njkayaker
It might (not sure).


I only know of the interior sensors. I'm not sure why they couldn't be used outside.


Black magic, I think. Actually, it looks like they have two antennas that are separated a bit. The mmwave sensors can detect breathing. It would seem it should have no problems detecting slightly different or changing speeds. The indoor sensors can track a limited number of objects (like 3).
"mm wave radar" refers to the wavelength of the radar. The smaller the wavelength (higher frequency) the more accurate the radar can be. Indoor mm wave radar devices (intrusion sensors) are cost effective because they are aimed at the mass market which drives the cost down due to high production volumes and competition between providers. The total number of bike radars sold will be a minuscule fraction of the indoor sensors sold.
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Old 05-15-24, 04:04 PM
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Originally Posted by PromptCritical
"mm wave radar" refers to the wavelength of the radar. The smaller the wavelength (higher frequency) the more accurate the radar can be. Indoor mm wave radar devices (intrusion sensors) are cost effective because they are aimed at the mass market which drives the cost down due to high production volumes and competition between providers. The total number of bike radars sold will be a minuscule fraction of the indoor sensors sold.
Why can't the bike radars use the same (or similar) sensors that are "cost effective"?

They aren't really "intrusion detectors". They are more than just that. They can track objects within a space. They can detect motion as subtle as breathing.
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Old 05-15-24, 04:09 PM
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Originally Posted by njkayaker
Why would anybody care?

Your "whys" were kind of dismissive too.


So, it's something you don't know much about and don't care to learn anything about. Is telling people you are "not interested" in it at all useful to them? (Hint: no, it's not useful at all.)
About as useful as your unprovoked attacks. However, it's a forum and we each post reflective of our worldviews.

Some say what they think, others prefer to attack what people think. So, you be you and I'll be me.
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Old 05-15-24, 04:16 PM
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Originally Posted by FBinNY
About as useful as your unprovoked attacks. However, it's a forum and we each post reflective of our worldviews.

Some say what they think, others prefer to attack what people think. So, you be you and I'll be me.
Again, people can comment about your comments. Even criticize them. You shouldn't say misleading things (the "dive into the shoulder" nonsense) and expect to immune comments about that.

Originally Posted by FBinNY
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
Why have this in your sig?

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Old 05-15-24, 04:18 PM
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Originally Posted by njkayaker
Again, people can comment about your comments. Even criticize them. You shouldn't say misleading things (the "dive into the shoulder" nonsense) and expect to immune comments about that.
Absolutely. Feel free to continue being who you are. May you future be filled with people of similar mindset.
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