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Which camera to use?

In our company we glue items together that have a very small tolerance. So I had this idea to have a camera system connected to a RPi that enlarges the corners where we mount the item. So instead of looking at a 10x10mm square you look up at the monitor and you see a 80x80mm square so that you're spot on. 
Now the problem I have is I don't know what camera to use to connect to the Pi. The standard Pi camera has no zoom ability. The cameras would ideally be about 300mm from the surface we are working on. 
Any suggestions where to look or do you perhaps have a better solution?

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March 12, 2020 09:07

You might look at this one:
https://www.adafruit.com/product/636

It is higher resolution (5Mpix) than many similar units, has built-in LEDs, USB interface, and is relatively inexpensive. I haven't used it myself. I'm not sure it will work well at 300mm, though - it is best at 50 - 100mm. That seems true of many units out there.

RS has https://uk.rs-online.com/web/p/microscopes/9132490/ , which connects wirelessly. It is lower res (656x492), but the spec sheet does list a field of view at 157mm working distance of 39x29mm. That works out (at that distance) to 16+/- pixels per mm.

You can do a web search for USB microscope to find many choices, but many of them share the lack of longer working distance.

One parameter that isn't always on a spec sheet is how much lag there is between capture and display. It is unimportant for still capture applications, but can be important if you are relying on video for positioning feedback. Sometimes reviews will mention whether there is lag or not.

I also recall a youtube video on modifying a web cam with a lens to get a very good combo of res and working distance. The poster offered an appropriate lens for sale. That was years ago.

March 17, 2020 17:02

@BradLevy the adafruit camera you recommended looks great! I like the manual zoom function. Thank you for the suggestion.

March 17, 2020 17:03

@BradLevy Thank you for your reply. I will have a look at those recommendations. We can lower the 300mm working height but not much as space is needed to get your hands under the camera to position the material. Maybe 200mm will be sufficient? I will run some tests and revert back.