IR curtain

Thread Starter

grcshekar

Joined Jan 8, 2020
31
Hi Experts There !

Can you please help me with circuit and components for a IR curtain which would cover 2.5 feet of width and 2.75 feet of height. When beam is intercepted it should either send a HIGH or LOW signal to Arduino
 
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KeithWalker

Joined Jul 10, 2017
3,063
What kind of resolution are you aiming for? In other words, what is the size of the smallest device you want to detect. That will define what you will need.
Regards,
Keith
 

MisterBill2

Joined Jan 23, 2018
18,167
You are describing an industrial light curtain, used for protecting operators. They are available in many sizes and a lot of variations. Normally they would connect to industrial automation system safety controllers, not an arduino. If this is a safety application no arduino hardware could possibly gain acceptance.
 

Bernard

Joined Aug 7, 2008
5,784
Some ramblings:
Keep beam width narrower than spaces , may need short focus lens on Tx., conical concentrator on Rx. Non modulated is simpler.
Can the beams be horizontal, less apt to collect trash?
 

MisterBill2

Joined Jan 23, 2018
18,167
OK, the systems that I have used were to keep machines from running when hands or fingers were near moving parts. The TS has given no clue as to what this is for, or how important reliability and performance would be.
For home fabrication and applications I suggest small cheap lasers and phototransistors as detectors. Narrow beam LEDs are not available to most folks, and the logic to make the wider beam ones work gets large. With LEDs the beams need to come on in sequence and the opposite detector needs to be checked only at that time. And they do it a few times per second. Lasers could all flash at the same time, a few times per second, and all of the sensors could be checked at once. Much simpler.
 

Thread Starter

grcshekar

Joined Jan 8, 2020
31
OK, the systems that I have used were to keep machines from running when hands or fingers were near moving parts. The TS has given no clue as to what this is for, or how important reliability and performance would be.
For home fabrication and applications I suggest small cheap lasers and phototransistors as detectors. Narrow beam LEDs are not available to most folks, and the logic to make the wider beam ones work gets large. With LEDs the beams need to come on in sequence and the opposite detector needs to be checked only at that time. And they do it a few times per second. Lasers could all flash at the same time, a few times per second, and all of the sensors could be checked at once. Much simpler.
Yes but how to do this
 

Thread Starter

grcshekar

Joined Jan 8, 2020
31
What kind of resolution are you aiming for? In other words, what is the size of the smallest device you want to detect. That will define what you will need.
Regards,
Keith
Aiming to detect any object passing through beam as low as 1 cm from ground to 2.75 feet
 

Thread Starter

grcshekar

Joined Jan 8, 2020
31
Some ramblings:
Keep beam width narrower than spaces , may need short focus lens on Tx., conical concentrator on Rx. Non modulated is simpler.
Can the beams be horizontal, less apt to collect trash?
Can be horizontal, but I need full details including components and circuit
 

KeithWalker

Joined Jul 10, 2017
3,063
Can be horizontal, but I need full details including components and circuit
What is your electronic knowledge level and experience? I doubt whether anyone on the forum is prepared to invest their precious time in designing and developing a complete custom system for you, especially when you can by a ready built and tested unit. If you insist on building your own, I would suggest you start doing some research on the subject so that you can design it yourself.
Regards,
Keith
 

dendad

Joined Feb 20, 2016
4,451
Usually, the best way to get help is to post your attempts at the project and folks here will suggest changes as required.
So, do some research and draw up circuits than ask again. If you are not wanting to do a bit of work, I reckon you need to go and buy an over the counter one.
Most of the time, this forum is to help you learn stuff, not do it for you.
 

atferrari

Joined Jan 6, 2004
4,764
The objects passing through "the beam" (I expect them to be "many beams"), are moving along the bottom line or could they be passing with they lower end at any height?

If you prepare a sketch showing all the possible bodies passing through, it could help you to have some ideas of your own. Otherwise, your are requiring a full design service and that could cost dearly.

Curious: are you usually mixing cm with inches? Do you recognize the difference? I work with both types of units in my daily job but never mix them. :oops:
 

MisterBill2

Joined Jan 23, 2018
18,167
What is your electronic knowledge level and experience? I doubt whether anyone on the forum is prepared to invest their precious time in designing and developing a complete custom system for you, especially when you can by a ready built and tested unit. If you insist on building your own, I would suggest you start doing some research on the subject so that you can design it yourself.
Regards,
Keith
A good light curtain is not simple, no matter what. How far apart can the light beams be? That is what the question about resolution means. Will you be able to produce the mounting arrangement to accurately point each light source at the detector it is going to work with? Is the purpose of this system to provide safety by stopping a machine when it is triggered, or is it for security, to send an alarm when something breaks a beam? The application matters a whole lot. We need to understand a lot more about this potential application.
 
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Reloadron

Joined Jan 15, 2015
7,501
Yes am sure
Then here is what I suggest you do. Purely for a home project and nothing industrial where life or limb may figure into things. I would go buy some of these or maybe some of these. All you need is a starter pack for a proof of concept and that takes care of the transmitter side. Then while you are at it buy some of these also so that takes care of the receiver end. Actually the plain sensors can also be bought so you don't need a few parts on the modules I linked. A Google of LASER Sensors or photo transistors should find some. I have played with some of those I linked to but have never really looked at the LASER dispersion over any distances so that is why I suggest buy a few and do a proof of concept. Get a few boards and drill mounting holes for the transmitters and receivers at precise intervals.

Again if this is for a home brew kitchen table project then fine but for anything industrial you can buy a LASER Light curtain designed for safety.

Ron
 

MisterBill2

Joined Jan 23, 2018
18,167
OK, so the system needs to trigger on a 1CM object. That means that beam spread could easily be a problem unless lasers are used. An interesting concept would be a laser and a whole bunch of mirrors so that one beam could cover a very large area. But aiming an invisible beam would be a huge problem.
 

MaxHeadRoom

Joined Jul 18, 2013
28,617
I would be looking in the direction of Ron's thread #16, the output of the receivers could all be ANDED using opto isolators, this would also provide some kind of fail safe detection.
Input to a Micro etc should be easy as long as fail-safe methods are used and simulate the industrial version.
Max.
 

Chris65536

Joined Nov 11, 2019
270
OK, so the system needs to trigger on a 1CM object. That means that beam spread could easily be a problem unless lasers are used.
We have a bunch of light curtains at work, and I'm pretty sure they are all LED, not Laser. It cycles through each LED on the transmitter side, while reading *all* the sensors on the receiver side each time. This gives a sort of mesh of sensing lines, instead of just the individual rows. The LEDs need to have a wide enough angle to reach all of the sensors. The good ones in my experience are from Omron, formerly STI. I have also used Banner and Keyence. These all follow serious safety requirements, and they are not cheap. But I have never considered building my own. This is one I'll leave to the experts!
 
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