Other good optics forums?

Post by g***@gmail.com
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

Mike S

2017-10-02 23:05:58 UTC

On 10/2/2017 8:29 AM, ***@gmail.com wrote:
<snip>

Post by g***@gmail.com
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.

g***@gmail.com

2017-10-02 23:53:36 UTC

Post by Mike S
<snip>

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.

Phil Hobbs

2017-10-03 00:33:48 UTC

Post by Mike S
<snip>

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

Jeroen Belleman

2017-10-03 08:16:38 UTC

Post by Mike S
<snip>

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

g***@gmail.com

2017-10-03 17:12:42 UTC

Post by Jeroen Belleman

Post by Mike S
<snip>

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.

Jeroen Belleman

2017-10-04 07:15:18 UTC

Post by Jeroen Belleman

Post by Mike S
<snip>

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

Phil Hobbs

2017-10-04 14:29:47 UTC

Post by Jeroen Belleman

Post by Mike S
<snip>

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

whit3rd

2017-10-10 00:08:37 UTC