Looking for a photo sensor


Thread Starter


I am looking for some type of photo sensors in my project which is: Putting 100 dental burs( needle shaped) into 100 2mm diameter holes on a 3*3 inch wide steel pallet.The holes go through the pallet. When the burs are inserted into the holes, will block them.

I need something kind of photo sensor to detect if all the holes are blocked.If there is one or more burs are not inserted into the holes, a receiver can see the light coming through the hole from the emitter and give a failure warning.

Can anybody kindly give me some ideas or recommand me some photo sensors for this project? Any of your help will be greatly appreciated.

Curt Wuollet

I've done very similar things with an inexpensive board camera, a frame grabber card, the Linux V4L drivers and a page or so of C code. But any of the low end machine vision packages should be able to handle this, albeit at much higher cost. Banner makes some crude systems that don't require a PC except for setup. Just be sure your camera mounting and fixturing are rock solid or keeping it calibrated will drive you crazy.


Michael Griffin

You could try a conventional through-beam sensor (emitter-receiver pair). The sensitivity however may not be good enough, and the field of view too narrow. A low cost vision system with back lighting may be more reliable.

Steve Myres, PE

You could certainly do this with a vision system, or possibly use a line type emitter receiver pair (non safety light curtain). Since you're probably indexing the pallet or loader one row pitch at a time, just index the light curtain right along with the loader let the pallet move across under the sensor. The light curtain can look at an entire row of 10 at once and report if any holes are open, and if so, the location.
Many Thanks to Steve, Michael and Curt. Emitter receiver pair seems a good choice in a economic view but just like Micheal said, the sensitivity is my main concern.