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  • Other good optics forums?

    From Phil Hobbs@21:1/5 to ggherold@gmail.com on Mon Oct 2 11:39:24 2017
    On 10/02/2017 11:29 AM, ggherold@gmail.com wrote:
    Sci.optics seems dead. Any other good places?

    Someone pointed me to the DT35 distance measuring device. https://www.sick.com/us/en/distance-sensors/mid-range-distance-sensors/dx35/dt35-b15251/p/p295353

    And I was wondering how it worked. (What's inside.)

    George H.


    The alt.lasers crowd mostly went to photonlexicon.com, I think. There
    are still a bunch of us here, just not many questions these days.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC
    Optics, Electro-optics, Photonics, Analog Electronics

    160 North State Road #203
    Briarcliff Manor NY 10510

    hobbs at electrooptical dot net
    http://electrooptical.net

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ggherold@gmail.com@21:1/5 to All on Mon Oct 2 08:29:04 2017
    Sci.optics seems dead. Any other good places?

    Someone pointed me to the DT35 distance measuring device. https://www.sick.com/us/en/distance-sensors/mid-range-distance-sensors/dx35/dt35-b15251/p/p295353

    And I was wondering how it worked. (What's inside.)

    George H.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Mike S@21:1/5 to ggherold@gmail.com on Mon Oct 2 16:05:58 2017
    On 10/2/2017 8:29 AM, ggherold@gmail.com wrote:
    <snip>
    Someone pointed me to the DT35 distance measuring device. https://www.sick.com/us/en/distance-sensors/mid-range-distance-sensors/dx35/dt35-b15251/p/p295353
    And I was wondering how it worked. (What's inside.)
    George H.

    did you read this yet?
    https://en.wikipedia.org/wiki/Proximity_sensor

    it's interesting, looking fwd to replies here.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to ggherold@gmail.com on Mon Oct 2 20:33:48 2017
    On 10/02/2017 07:53 PM, ggherold@gmail.com wrote:
    On Monday, October 2, 2017 at 7:06:01 PM UTC-4, Mike S wrote:
    On 10/2/2017 8:29 AM, ggherold@gmail.com wrote:
    <snip>
    Someone pointed me to the DT35 distance measuring device.
    https://www.sick.com/us/en/distance-sensors/mid-range-distance-sensors/dx35/dt35-b15251/p/p295353
    And I was wondering how it worked. (What's inside.)
    George H.

    did you read this yet?
    https://en.wikipedia.org/wiki/Proximity_sensor

    it's interesting, looking fwd to replies here.

    I'm guessing they are modulating the laser beam.
    The different ranges, will be different frequencies,
    to match different gains (of the TIA),
    as the intensity drops off.
    (But I don't know.)
    George H.


    There are a lot of ways of doing this. A sawtooth waveform is the simplest.

    Cheers

    Phil Hobbs



    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC
    Optics, Electro-optics, Photonics, Analog Electronics

    160 North State Road #203
    Briarcliff Manor NY 10510

    hobbs at electrooptical dot net
    http://electrooptical.net

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ggherold@gmail.com@21:1/5 to Mike S on Mon Oct 2 16:53:36 2017
    On Monday, October 2, 2017 at 7:06:01 PM UTC-4, Mike S wrote:
    On 10/2/2017 8:29 AM, ggherold@gmail.com wrote:
    <snip>
    Someone pointed me to the DT35 distance measuring device. https://www.sick.com/us/en/distance-sensors/mid-range-distance-sensors/dx35/dt35-b15251/p/p295353
    And I was wondering how it worked. (What's inside.)
    George H.

    did you read this yet?
    https://en.wikipedia.org/wiki/Proximity_sensor

    it's interesting, looking fwd to replies here.

    I'm guessing they are modulating the laser beam.
    The different ranges, will be different frequencies,
    to match different gains (of the TIA),
    as the intensity drops off.
    (But I don't know.)
    George H.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to Phil Hobbs on Tue Oct 3 10:16:38 2017
    On 2017-10-03 02:33, Phil Hobbs wrote:
    On 10/02/2017 07:53 PM, ggherold@gmail.com wrote:
    On Monday, October 2, 2017 at 7:06:01 PM UTC-4, Mike S wrote:
    On 10/2/2017 8:29 AM, ggherold@gmail.com wrote:
    <snip>
    Someone pointed me to the DT35 distance measuring device.
    https://www.sick.com/us/en/distance-sensors/mid-range-distance-sensors/dx35/dt35-b15251/p/p295353

    And I was wondering how it worked. (What's inside.)
    George H.

    did you read this yet?
    https://en.wikipedia.org/wiki/Proximity_sensor

    it's interesting, looking fwd to replies here.

    I'm guessing they are modulating the laser beam.
    The different ranges, will be different frequencies,
    to match different gains (of the TIA),
    as the intensity drops off.
    (But I don't know.)
    George H.


    There are a lot of ways of doing this. A sawtooth waveform is the
    simplest.

    Cheers

    Phil Hobbs




    It's not a simple proximity sensor. The datasheet says it
    sends 3ns red laser pulses with a 1/250 duty cycle. They must
    measure the echo return time, I suppose.

    Jeroen Belleman

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ggherold@gmail.com@21:1/5 to Jeroen Belleman on Tue Oct 3 10:12:42 2017
    On Tuesday, October 3, 2017 at 4:16:40 AM UTC-4, Jeroen Belleman wrote:
    On 2017-10-03 02:33, Phil Hobbs wrote:
    On 10/02/2017 07:53 PM, ggherold@gmail.com wrote:
    On Monday, October 2, 2017 at 7:06:01 PM UTC-4, Mike S wrote:
    On 10/2/2017 8:29 AM, ggherold@gmail.com wrote:
    <snip>
    Someone pointed me to the DT35 distance measuring device.
    https://www.sick.com/us/en/distance-sensors/mid-range-distance-sensors/dx35/dt35-b15251/p/p295353

    And I was wondering how it worked. (What's inside.)
    George H.

    did you read this yet?
    https://en.wikipedia.org/wiki/Proximity_sensor

    it's interesting, looking fwd to replies here.

    I'm guessing they are modulating the laser beam.
    The different ranges, will be different frequencies,
    to match different gains (of the TIA),
    as the intensity drops off.
    (But I don't know.)
    George H.


    There are a lot of ways of doing this. A sawtooth waveform is the simplest.

    Cheers

    Phil Hobbs




    It's not a simple proximity sensor. The datasheet says it
    sends 3ns red laser pulses with a 1/250 duty cycle. They must
    measure the echo return time, I suppose.

    Jeroen Belleman

    Jeroen, I couldn't find a data sheet. I did see some spec that claimed
    ~1mm resolution ~ 1 ps timing.. or something else.

    George H.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to ggherold@gmail.com on Wed Oct 4 09:15:18 2017
    On 2017-10-03 19:12, ggherold@gmail.com wrote:
    On Tuesday, October 3, 2017 at 4:16:40 AM UTC-4, Jeroen Belleman wrote:
    On 2017-10-03 02:33, Phil Hobbs wrote:
    On 10/02/2017 07:53 PM, ggherold@gmail.com wrote:
    On Monday, October 2, 2017 at 7:06:01 PM UTC-4, Mike S wrote:
    On 10/2/2017 8:29 AM, ggherold@gmail.com wrote:
    <snip>
    Someone pointed me to the DT35 distance measuring device.
    https://www.sick.com/us/en/distance-sensors/mid-range-distance-sensors/dx35/dt35-b15251/p/p295353

    And I was wondering how it worked. (What's inside.)
    George H.

    did you read this yet?
    https://en.wikipedia.org/wiki/Proximity_sensor

    it's interesting, looking fwd to replies here.

    I'm guessing they are modulating the laser beam.
    The different ranges, will be different frequencies,
    to match different gains (of the TIA),
    as the intensity drops off.
    (But I don't know.)
    George H.


    There are a lot of ways of doing this. A sawtooth waveform is the
    simplest.

    Cheers

    Phil Hobbs




    It's not a simple proximity sensor. The datasheet says it
    sends 3ns red laser pulses with a 1/250 duty cycle. They must
    measure the echo return time, I suppose.

    Jeroen Belleman

    Jeroen, I couldn't find a data sheet. I did see some spec that claimed
    ~1mm resolution ~ 1 ps timing.. or something else.

    George H.


    There's a link to a 9-page pdf datasheet on the web page you
    referred to. It doesn't give a whole lot of information, but
    enough to guess that it measures the round-trip delay of a short
    laser light pulse.

    Jeroen Belleman

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to ggherold@gmail.com on Wed Oct 4 10:29:47 2017
    On 10/03/2017 01:12 PM, ggherold@gmail.com wrote:
    On Tuesday, October 3, 2017 at 4:16:40 AM UTC-4, Jeroen Belleman wrote:
    On 2017-10-03 02:33, Phil Hobbs wrote:
    On 10/02/2017 07:53 PM, ggherold@gmail.com wrote:
    On Monday, October 2, 2017 at 7:06:01 PM UTC-4, Mike S wrote:
    On 10/2/2017 8:29 AM, ggherold@gmail.com wrote:
    <snip>
    Someone pointed me to the DT35 distance measuring device.
    https://www.sick.com/us/en/distance-sensors/mid-range-distance-sensors/dx35/dt35-b15251/p/p295353

    And I was wondering how it worked. (What's inside.)
    George H.

    did you read this yet?
    https://en.wikipedia.org/wiki/Proximity_sensor

    it's interesting, looking fwd to replies here.

    I'm guessing they are modulating the laser beam.
    The different ranges, will be different frequencies,
    to match different gains (of the TIA),
    as the intensity drops off.
    (But I don't know.)
    George H.


    There are a lot of ways of doing this. A sawtooth waveform is the
    simplest.

    Cheers

    Phil Hobbs




    It's not a simple proximity sensor. The datasheet says it
    sends 3ns red laser pulses with a 1/250 duty cycle. They must
    measure the echo return time, I suppose.

    Jeroen Belleman

    Jeroen, I couldn't find a data sheet. I did see some spec that claimed
    ~1mm resolution ~ 1 ps timing.. or something else.

    Resolution, sure--just average a million shots. Accuracy, not so much.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC
    Optics, Electro-optics, Photonics, Analog Electronics

    160 North State Road #203
    Briarcliff Manor NY 10510

    hobbs at electrooptical dot net
    http://electrooptical.net

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From whit3rd@21:1/5 to gghe...@gmail.com on Mon Oct 9 17:08:37 2017
    On Monday, October 2, 2017 at 4:53:37 PM UTC-7, gghe...@gmail.com wrote:
    On Monday, October 2, 2017 at 7:06:01 PM UTC-4, Mike S wrote:
    On 10/2/2017 8:29 AM, ggherold@gmail.com wrote:
    <snip>
    Someone pointed me to the DT35 distance measuring device.

    And I was wondering how it worked. (What's inside.)

    I'm guessing they are modulating the laser beam.

    Isn't it a lidar set? Frequency-swept outgoing chirps, and receiver that
    mixes down against the transmitter signal, so you get a low difference frequency

    F_difference = dF/dt * 2X/c

    ... that shows up on an FFT
    AGC is allowed (it's not an intensity-dependent signal).
    The receiver can be relatively low-gain, and AC coupled, which
    gets rid of lots of stray light issues, even if your (iight) filtering is sloppy.

    Looks like there's a lens, maybe collimator with a retroreflector for a target.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)