From: Bob Blick <bobblick@outlook.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Fri, 18 Sep 2020 12:36:20 -0700
Subject: Re: [EE] light sensor array?
Thread-Topic: [EE] light sensor array?
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That one is sort of down my alley. Commercial laser detectors for the const=
ruction industry are of two varieties - ones that work with rotating lasers=
 and ones that work with modulated lasers. Either of those make detecting t=
he laser a whole lot easier. Ambient light is another obstacle, both sunlig=
ht and AC powered LED indoor illumination.

If you describe the parameters a little more I might be able to give you so=
me tips.

Friendly regards, Bob

________________________________________
From: piclist-bounces@mit.edu <piclist-bounces@mit.edu> on behalf of Neil=20
Sent: Friday, September 18, 2020 12:11 PM
To: Microcontroller discussion list - Public.
Subject: [EE] light sensor array?

I want to measure the position (height) of a laser line level (device
that projects a horizontal line of light).  2" of measurement would be
nice, 1" I'd say is minimum.

First thought is that I could use a light sensor array (such as in a
sheet scanner), but this is a one-off project, and I'm not up for
finding one that I can hack and then trying to reverse engineer it right
now.
The ones I'm finding on Digikey etc (which will have datasheets) are
low-cost enough ($10-$20), but either have a very short range (~0.5" or
less), or the longer ones are discontinued.
Any recommendations for one of these?  I don't need high resolution
(even 1mm is fine).

Yes, I could put the sensor on a linear servo, but then I'd have to
ensure that mechanism is tight and not introduce any noticeable errors
in the system.

Alternate option is to let the light hit a diffuser (like say parchment
paper) and use a camera on the other side to detect the height of the
light line.  I'd have to (finally) learn openCV perhaps, but that's prob
fine.

Still thinking of other ways to do this too, even perhaps a curved lens
or mirror to compress a couple inches of range down to fit one of the
available sensors.

Brainstormy thoughts appreciated.

Cheers,
-Neil.



--=20
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