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Topic: Part Presence / Absence setup recommendations, (Read 1 time) previous topic - next topic


Team,  Can anyone help me idenify components required to set up an inspection station to verify th presence of holes?



Is it advice about the hole sensor you're looking for, or what?


I really need help with the entire project.

Sensor Types
the works


For a project like this I'd suggest Roborealm.

You haven't been at all descriptive of your project, but if you're describing holes in an object you can backlight then the illuminated holes should be easily identifiable with "blob count".


You are right.  I havent been that clear.  Ok, here I go. 

I have a thin sheet of steel that holes in it and I need to verify the absence of holes if they have inadvertently been missed in the drilling process.  I'm new to this stuff.



How big is the sheet, how big are the holes and roughly how many will there be, are the positions always the same, will that pattern of holes be subject to change in future, how many sheets do you need to scan, how long can you afford to spend scanning a sheet, what facilities do you have for moving the sheet or the sensing device into position for each sheet?


The part is 40"x 10" long.  There are 10 holes scattered throught.  I have approx 200 parts to check.   Per day.


Jun 17, 2012, 05:07 am Last Edit: Jun 17, 2012, 05:12 am by Techylah Reason: 1
That Roborealm looks awesome, but it doesn't fit on an Arduino and it might be overkill, not to mention the license fee.
Does the following humble suggestion fit the bill?
Sometimes the simplest solution is the best.

Take one known good sheet of steel and mount a photodiode sensor at each hole site.
You put it on a light table and cover it with glass or plexiglass.
Then you simply place each test sheet on it, hit a test button.
You save the sheet as your "program".
If you're clever, you can rig up magnetic mounts for the photodiodes so you can reuse them on any sheet.

Your Aduino simply reads the 10 digital inputs, counts them up, and sounds the alarm if it's not equal to ten, printing a message of the missing hole(s).


To push simplicity to the fullest, you don't even need the Arduino.  These photodiodes produce current when illuminated.

You can put ten of these in series across an Led and it will light the led if and only if all 10 diodes get light.
You could also insert a 9v battery in series to brighten the "On" condition.
Your test sheet is placed on top of your rigged one, which has a photodiode at each hole.
When you illuminate it, the Led will go on only if all photodiodes get light.  Any one in the dark keeps the light off.
You then would manually check which hole is missing.  You do get a quick instant and reliable pass, though.

You could expand the Arduino solution to general purpose and have a dozen or more inputs.
You take a new good sheet and stick any of the magnetic mounted diodes on each hole.
You'd have a "Learn" button which, when pressed, learns which ones have to see light in order to pass.
You then have a big "Test" button that sounds the alarm if the new readings don't match the learned one!


Thanks for the info.  I'll check into your suggestion.

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