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My application needed to measure human height on a standing kiosk. I need to attach the sensor on kiosk ceiling type top. I used different kind of ultrasonic sensor for this purpose but nothing proving reliable results.

First, general ultrasonic sensor have deadband within which the sensor doesn't work and second human head and should varies and thus the reflecting pattern. Can anyone suggest the best method and sensor to use for this purpose? I didn't use laser till now because of eye safety reasons.

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  • $\begingroup$ Any error caused by hair and hairstyle? $\endgroup$ – Solar Mike Apr 5 '18 at 6:13
  • $\begingroup$ Yes, hair also causes error in reading. $\endgroup$ – Prasan Dutt Apr 5 '18 at 6:17
  • $\begingroup$ Best is not defined. Anyway a time of flight laser wont work any better than the ultrasonic. I would try to use somekind of 3D camera system. Some of those admittedly many also use infrared lasers, which arent visible, but works by triangulation. $\endgroup$ – joojaa Apr 5 '18 at 6:28
  • $\begingroup$ Thanks for your input. I am looking into these options for putting a 3D camera for height measurement seems very costly option. $\endgroup$ – Prasan Dutt Apr 5 '18 at 8:19
  • $\begingroup$ Do the people at the kiosk have instructions to stand with a proper posture? If not, slouching and leaning or perhaps some physical problem may cause errors of a few centimetres, which cannot be corrected by a simple sensor system. $\endgroup$ – ChP Apr 6 '18 at 10:42
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Hair is mostly transparent to ultrasonic, so this is still the reliable&convenient approach - any EM spectrum readouts (3D, video, laser) will be completely falsified by hair.

You just need a narrow cone ultrasonic sensor - one with readout area restricted to top of the head. It's not something to be found in robotics/industrial equipment supplies, but ones qualified for medical use should work. This is still not 100% reliable, but allows for quick, easy, contactless measurement.

The only 100% reliable but way less convenient method is mechanical - like a stadiometer. Electronic determination of the position of the slider should be vastly easier, e.g. using a linear encoder with Grey code encoded positioning.

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  • $\begingroup$ May you suggest any such supplier qualified for medical use? My search resulted in Maxbotix and Senix, any other suggested names will be helpful. $\endgroup$ – Prasan Dutt Apr 7 '18 at 5:02
  • $\begingroup$ @PrasanDutt: Sorry, not my area of expertise - I stumbled upon these in my searches through catalogues but they were not what I was looking for, so I didn't really remember anything specific about them. $\endgroup$ – SF. Apr 8 '18 at 20:59

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