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Is there any emitter/receiver (passive or active) systems that allow distance estimation in the range of 1~2 meters with an accuracy of few centimetres and don't need to have a direct line of sight as optical systems mostly do?

I was thinking about using such sensors as nodes to put on a suit that a human can wear. As a result, a graph can be obtained where each node represents one of those sensors and each edge describes the distance from this node to the other nodes. Using graph optimization techniques, the graph would converge to the correct joint position of the human. Such a system could replace expensive motion capture methods using calibrated external cameras.

706Astor
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Mehdi
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2 Answers2

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I think you have approached your problem from the wrong direction. There are currently no sensors that measure distance between each other regardless of material in the path. It would be possible to make a device with optical or ultrasonic time of flight technology, but that would be a project all by itself. These sensors are very expensive and need calibrated for a fixed environment. It would require lots of development to remove all the variables from a biomechanics type application.

I recommend you look at currently available sensing technology and look how you can apply those sensors in new ways. Optical is likely the future in this field. Computer software can be written to splice multiple images and reverse render the position and texture of objects. If this still does not solve the problem, you could look at using wavelengths outside the visible spectrum such as near infrared.

ericnutsch
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Ultrasonic sensing is can be used for distance measurement. Ultrasonic proximity sensing technology is commonly used in automotive as part of Advanced Driver Assistance Systems. The basic theory behind this technology is Time-of- Flight (TOF). Below few images to help visualize the idea.

Park Assist-1 Park Assist-2

To achieve this you can use PGA450 Ultrasonic Analog Front End (AFE) from Texas Instruments. As I understand this sensor is capable of distances up to 7M.

The PGA450-Q1 device can measure distances ranging from less than 1 meter up to 7 meters, at a resolution of 1 cm depending on the transducer-transformer sensor pair used in the system.

Below is a diagram describing the concept.

PGA450 AFE

Also you might want to check out TDC1000 Ultrasonic AFE. I am much more familiar with this part. But I have not used this part for proximity sensing. Once again below is a diagram describing the application.

TDC1000 AFE

Also TDC1000 has a configuration where the emitter and receiver are seperate that might be interesting.

TDC1000 AFE Separate emitter and receiver

Below are some references that you might find interesting

References

Community
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Mahendra Gunawardena
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