From: Denny Esterline <desterline@gmail.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
Sender: "piclist-bounces@mit.edu" <piclist-bounces@mit.edu>
Date: Fri, 18 Sep 2020 12:50:56 -0700
Subject: Re: [EE] light sensor array?
Thread-Topic: [EE] light sensor array?
Thread-Index: AdaN9pCKdGscxpyMTnajtKZZkBP5Tg==
Message-ID:
 <CADOftefYrBWFDT+=a7JFm9Vn3eZNaP+Hy5wwbBOocgt-oijuhw@mail.gmail.com>
References: <5F65066E.6040408@narwani.org>
In-Reply-To: <5F65066E.6040408@narwani.org>
Reply-To: Microcontroller discussion list - Public. <piclist@mit.edu>
Accept-Language: en-US
X-MS-Exchange-Organization-SenderIdResult: TempError
X-MS-Exchange-Organization-PRD: mit.edu
X-MS-TNEF-Correlator:
received-spf: Pass (protection.outlook.com: domain of gmail.com designates
	209.85.128.45 as permitted sender) receiver=protection.outlook.com;
	client-ip=209.85.128.45; helo=mail-wm1-f45.google.com;
dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com;
 s=20161025;
	h=mime-version:references:in-reply-to:from:date:message-id:subject:to;
 	bh=boMq45WKByWD5wLC1/iWFX1GpNrBTpRoV0EHmbDKeMU=;
	b=U8UwM0+Ak+vgUXMPc+NHaDhJdj5XiE1vdtBc+n0zdgtZLlyMlOVIRbpBRVbXdRJ2hA
	i1v3e+wmrCzuRQ8kLAFHvtXGxq574DX0XI6kBZDz8TElY2rVzHTf6njDhouDscpPq46Z
	SInsjwKc13Esytp8NMYvE04p6H3x4tdCrIkizcxxZICc2wDbUI9qATmWJ4+Rebu2U1eY
	x9XIvo/WUJSYGmDqWeZPzV9HoQMQXWx9+RvvZkGfC7sPsiGRXXzsYcd+2oUNGnfeew1D
	JUhs2EJx/SmhMXy98J0/9C2XJFUOsvJFMoAYy5wb3n+v6sFoajj+bi0HFBfL+d3VV1TJ	7H2w==
authentication-results: spf=pass (sender IP is 209.85.128.45)
	smtp.mailfrom=gmail.com; mit.edu; dkim=pass (signature was verified)
	header.d=gmail.com; mit.edu;	dmarc=pass action=none header.from=gmail.com; 
errors-to: piclist-bounces@mit.edu
list-id: "Microcontroller discussion list - Public." <piclist.mit.edu>
list-post: <mailto:piclist@mit.edu>
x-beenthere: piclist@mit.edu
x-mailman-version: 2.1.6
x-received: by 2002:a7b:c085:: with SMTP id
 r5mr18160595wmh.52.1600458668181; 	Fri, 18 Sep 2020 12:51:08 -0700 (PDT)
x-topics: [EE]
x-content-filtered-by: Mailman/MimeDel 2.1.6
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0

That's a pretty wide open description, but one thought that occurs is
construction surveying laser receivers. A couple different categories, some
handheld with a display of some sort, the other type gets mounted to
earthmoving equipment (bulldozers, etc) and has an output that is used to
control the grade height.

No experience with this company, but their web site shows several options
of both types and has listed pricing:
https://www.engineersupply.com/construction-lasers.aspx
Look for "Laser Detectors" and "Machine Control Laser Detectors"

Food for thought at least.
-Denny



On Fri, Sep 18, 2020 at 12:15 PM Neil <picdude3@narwani.org> wrote:

> 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.
>
>
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.