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Per Westermark
03/17/12 14:31
Read: 544 times
Sweden


 
#186758 - Mirrors or multiple beams - still extremely cheap
Responding to: ???'s previous message
Damir Tadic said:
I was thinking about solution cheaper than industrial photoelectric sensor, devices like this http://www.balluff.com/Balluff/u...ensors.htm

Maybe solution is 3-4 IR LED / phototransistor pairs? One IR beam will not detect smaller object.

So use whatever number of beams you need. The cost for each beam is still extremely (!) low.

Or make it more interesting by bouncing the same light beam multiple times between mirrors before you detect it.

If you do not know the material, you can't play with capacitance or magnetic sensors.

Optical sensors can often be used even for transparent objects - because the transparent objects tends to reflect and refract, thereby stealing the beam.

If the object may be transparent, you could consider having beams in multiple directions - for example three sets of beams at 60 degree angle. That would make it very hard for a transparent object to pass through all three sets without reflecting or refracting away any of the beams.

List of 23 messages in thread
TopicAuthorDate
counting objects inserted in tube      Damir Tadic      03/17/12 02:28      
   Cheaper?      Per Westermark      03/17/12 06:44      
      counting objects inserted in tube      Damir Tadic      03/17/12 11:31      
         What is the purpose of counting?      Andy Neil      03/17/12 11:42      
         Mirrors or multiple beams - still extremely cheap      Per Westermark      03/17/12 14:31      
         I guess there is a language problem here      Erik Malund      03/17/12 17:52      
            Specification Inadequate - Language Barrier?      Andy Neil      03/18/12 01:45      
               determine when receptacle at end of tube is full - Deja Vu?      Andy Neil      03/18/12 01:47      
            Language Barrier      Damir Tadic      03/18/12 13:54      
               "Simple and cheap" or dead reliable?        Kai Klaas      03/18/12 15:47      
               Not a solution?      Andy Neil      03/19/12 01:02      
               simple and cheap      Erik Malund      03/19/12 06:56      
   Do you know...      Kai Klaas      03/17/12 07:07      
   I hope      Erik Malund      03/17/12 08:45      
      eh?      Andy Neil      03/17/12 11:31      
         eh?      Erik Malund      03/17/12 17:42      
            Possible      Andy Neil      03/18/12 01:33      
               All This Pontificating....      Michael Karas      03/18/12 03:00      
                  Is a answer more important than the "correct" answer?      Per Westermark      03/18/12 04:17      
                     Sprung door with microswitch.      David Prentice      03/18/12 04:53      
                        Maybe but the bigger question was: what was tram destination      Per Westermark      03/18/12 06:17      
                        Already been suggested!      Andy Neil      03/18/12 08:10      
                  That information was not initially available      Andy Neil      03/18/12 08:07      

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