As the title implies , i'm looking for a device that can detect at what point a laser beam has been broken. So idea would be the device to output a certain voltage depending on where someone's finger has broken the beam.
Does such a device exist?
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\$\begingroup\$ A laser displacement sensor. Typically designed for small distances (sub mm. and mm), but there are many out there for long distances (meters?) as well. These tend to be reflective sensors using triangulation for short distances, and maybe time of flight for long distances. \$\endgroup\$– Chris KnudsenCommented Dec 12, 2018 at 22:14
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\$\begingroup\$ Pls define aperture and range then threshold of break with tolerances. Then yes a custom design is trivial. \$\endgroup\$– D.A.S.Commented Dec 12, 2018 at 22:20
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\$\begingroup\$ Laser "measuring tapes" are easily available, and quite accurate. You probably won't be able to access their data for your project, but it might be worth looking into. Here is a good quality product from Bosch. You can find cheap knock-offs for less than half that cost. \$\endgroup\$– bitsmackCommented Dec 12, 2018 at 23:20
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1\$\begingroup\$ Why would you want such a device. Please justify your question so that a better insight to your thinking might yield a reliable and useful answer. \$\endgroup\$– Andy akaCommented Dec 13, 2018 at 0:07
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\$\begingroup\$ any glass-cased diode can do this \$\endgroup\$– analogsystemsrfCommented Dec 13, 2018 at 4:06
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2 Answers
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What you're looking for sounds more like a laser range finder. There are a number of different types of these that works in various ways, depending on your application, some might be better than others. If you say what exactly you're trying to do it will be easier to help you.
EDIT: Have a look at these, you'll need to figure out what range you want to it work over (I imagine probably about 1m?) and what frequency you need the measurements at (how quickly do you want a note to change?).
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\$\begingroup\$ thanks for response! I'm hoping to use in an audio application where breaking the beam at any particular point will output a note. The user would play it like a piano, substituting key press with laser beam break. \$\endgroup\$ Commented Dec 12, 2018 at 22:18
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\$\begingroup\$ I think that, from your description, you are basing the note from the distance of where the laser breaks (aka where its hit). This again points to a laser range finder, but a commercial one will (most likely) not give you an option to output any useful values. This is where the microcontroller comes in - you could use an Arduino with a laser module (if such one exists) to interpret the distance values, then program different notes based off of your own distance inequalities. Just something to bear in mind with these sorts of projects. \$\endgroup\$ Commented Dec 13, 2018 at 22:01
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I think you need to clarify whether you mean a sensor to detect where across the beam profile an obstruction is present, or if you mean a sensor to detect the range from the laser head to some target, or something else.
If you mean the first option, then you're probably looking for a CCD camera. This is essentially an array of photodiodes, giving a voltage corresponding to the amount of light incident on each pixel. By reading out this video you can find the region in which the finger breaks the beam. But if you're just wanting to detect a few different levels, you could just use a few photodiodes stacked in a line and then use a microcontroller to count how many of them are blocked, and therefore infer how far the finger has crossed into the beam.
