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do infrared sensor can pass through transparent plastic and work?

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closed as unclear what you're asking by JYelton, Chris Stratton, RoyC, Lior Bilia, Oleg Mazurov Aug 16 at 21:06

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • \$\begingroup\$ Just use your eyes is my advice or, if you are a little visually impaired ask someone to help. \$\endgroup\$ – Andy aka Aug 1 at 13:59
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    \$\begingroup\$ There are two ways to answer this question: try it yourself, or look up the IR absorption spectra of the types of plastic used in this kind of packaging. \$\endgroup\$ – Dave Tweed Aug 1 at 14:01
  • \$\begingroup\$ Probably, but don't rule out the possibility of remains of the foil backing and/or distortion of the plastic bubble providing some occlusion. Another direction to the apparent problem to consider could be computer vision, ie, webcam and OpenCV, first on a PC later on an embedded Linux board. \$\endgroup\$ – Chris Stratton Aug 1 at 14:02
  • \$\begingroup\$ @Chris Stratton thank you, do Is there another cheap way Except infrared? camera and OpenCV is expensive \$\endgroup\$ – user8591 Aug 1 at 14:11
  • \$\begingroup\$ Actually webcams and computing power are pretty cheap; presumably to do it with IR sensors you are going to need a bunch of them and fixturing; you can probably prototype with a 3d printer but then you'll need mold tooling... Granted the vision approach has alignment and lighting challenges so there are tradeoffs all around. \$\endgroup\$ – Chris Stratton Aug 1 at 14:16
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Your eyes cannot see IR but your (phone) camera can!

Grab your TV remote as an IR source and while pressing a button on the remote look at the remote through your phone's camera (actually almost any digital camera will do).

Chances are you will see the IR transmitter LED in the TV remote flashing like so:

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Now hold the pills package in between and check if you can still see the IR LED flashing.

If yes: then the IR light can pass through the holes in the package.

However, the aluminium (?) foil in the pills package will block IR very effectively. If that foil is not removed then the IR light will not pass through.

Only if there is a clear visible hole left (through which you can see light pass through) can this work reliably as a pill present/not present detector.

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  • \$\begingroup\$ thank you, do Is there another cheap way Except infrared? \$\endgroup\$ – user8591 Aug 1 at 14:06
  • \$\begingroup\$ @user8591 Welcome to Stack Exchange! If you have a second question, you should create another question post instead of posting your second question as a comment. \$\endgroup\$ – Tanner Swett Aug 1 at 14:13
  • \$\begingroup\$ @TannerSwett thank you , ok \$\endgroup\$ – user8591 Aug 1 at 14:16
  • \$\begingroup\$ Some brands of phone cameras can not see IR. \$\endgroup\$ – Charles Cowie Aug 1 at 14:38
  • \$\begingroup\$ That is true, Apple devices tend to have fairly good IR filters; sometimes "cheaper is better" a budget webcam is likely very susceptible. \$\endgroup\$ – Chris Stratton Aug 3 at 17:32

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