Need create a system for control position of spotrsmens and ball on a field

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Hello! We need a system what may detect motion and position sportmen and ball on a field. I found a solution - Marvelmind Starter Set HW v4.9-IMU Indoor Navigation Positioning System (915MHz) , but I’am not sure - it’s allow take pos data from >1 objects on field? We need look at 20 sportsmens and 1 ball. Or I can order also Marvelmind Indoor Beacon Mini-RX (915MHz) and plug it?

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Hello @anatoly and welcome to the RobotShop community,

Yes, you can use the Marvelmind Starter Set HW v4.9-IMU Indoor Navigation Positioning System (915MHz) to detect the motion and position of up to 30 mobile beacons but keep in mind that that kit only 1 mobile beacon so you will need to get 20x Marvelmind Indoor Beacon Mini-RX (915MHz) to be able to track 20 sportsmens and 1 ball.

You can see a demo video here:

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Hi Geraldine! Thank you for ansewer! But one question - how max frequency is possibilities in Hz/sec (samples/second)?

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Wait, 1 mobile module must plug to object on open surface? We can’t just wear it under armore? I think what mobile (radio-point on object) it small box - https://www.robotshop.com/en/marvelmind-indoor-beacon-mini-rx-915mhz.html that’s right? Not is that - https://www.robotshop.com/en/marvelmind-navigation-positioning-mobile-beacon-mini-tx-915mhz.html?
Because ultrasonic wave has not go throught any barrier (wear, leather - if we want put sensor into ball)…

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Non-Inverse Architecture:

  • 0.05–25Hz
  • Can be set manually or in automatic mode
  • Depends on the distance between the mobile and stationary beacons (shorter distance — higher update rate)
  • Depends on the number of mobile beacons: for example, update rate of 25Hz for 1 mobile beacon will result in update rate of 25Hz/2 for 2 mobile beacons, and 25Hz/3 – for 3 mobile beacons, etc. – TDMA approach
  • Depends on the radio interface profile (500kbps vs. 38kbps)

Inverse Architecture:

  • 0.05–25Hz. With IMU fusion enabled – up to 100Hz
  • Can be set manually or in automatic mode
  • Depends on the distance between the mobile and stationary beacons (shorter distance — higher update rate)
  • Doesn’t depend on the number of mobile beacons – all of them are receiving
  • Depends on the radio interface profile (500kbps vs. 38kbps)
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Yes, it must be placed on the object you want to track in an open and horizontal surface as high as possible. You can find some tips on how to place the beacons in this manual (page 17).

Yes, the mini RX (receiver) and TX (transmitter) are small, around 47 x 42 x 15 mm

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However, as you mentioned, if you were planning on putting the beacon inside the ball that won’t work because it is an ultrasonic sensor.

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Thank you! Hm, but may be existing analog systems that work only by radio frequency (not ultrasonic)?

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Yes, there are and you can find them in the Localization & GPS section of the store. However, I’m not very familiar with this type of application and I don’t know much about the electrical properties of the material used to make the ball and what frequencies could pass through it.

I can only think of some kind of tag like RFID but I don’t know if this technology could be applied to your application. It also occurs to me that you could use vision-based systems with OpenCV for example

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