Looking for recommendations on a project that needs to track movement of ~30m over about 15 min

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I do part-time work for a laser tag arena, and I’ve gotten a game prop request for a laser tag scenario that requires players from one team to drag a rescue dummy from a “danger zone” where the environment slowly kills them, to a “safe zone” between 20-50 meters away where they’re no longer being hurt within about 10-15 minutes. The idea being the players are rescuing a scientist from a nuclear reactor leaking radiation.

I’ve got a few ideas on how to make this work, but I don’t have much experience with the necessary sensors for each of the ideas I had, so I’m looking for any feedback on what would be the simplest and most foolproof way to do it. These are just my first thoughts, so if I missed any obvious ideas, I welcome suggestions! The prop can be a single box (right now I’m thinking it would be contained in a box that looks like a geiger counter mounted on the dummy), or it could be multiple devices. I have to avoid using anything IR based, since it may interfere with the laser tag game components. Here are my first-pass ideas:

  1. Dead reckoning with an IMU. I haven’t tried dead reckoning with an IMU before, and I understand errors accumulate quickly, but this game only takes 15 minuets, and I only have 20-50 meters to measure. My thought was to place a unit on the dummy that looks like a geiger counter with an IMU and the IR LED’s causing the damage which slowly decreases the further away it gets from its origin point.
  2. Measuring radio strength, or triangulation. Maybe put some kind of radio homing beacon at the safe zone, and have a unit on the dummy that measures the strength of the signal, and inversely dish out damage until the strength is high. I feel like this one is highly inaccurate and variable based on the amount of interference, but maybe that would mimic radiation – I dunno. It also may depend on the signal type used. Someone also suggested an indoor positioning system using triangulation with Bluetooth/Wi-Fi. This may be much more accurate with this kind of application than I’m thinking, but one requirement is that it needs to be set up and taken down fairly quickly, as this isn’t a permanent game.
  3. Measuring UV light strength. Same kind of idea as above, but flood the “danger zone” with UV light and use a UV light sensor on the unit to measure intensity of the damage. I like this one the least, because it’s too easy for the players to cover the light sensor or otherwise block the UV, but it’s definitely an option.
  4. GPS. I did a quick check of GPS sensors, and there are some modules that would be cost effective for this application if they worked reasonably well. This game is indoors, though, and I don’t know how well the cheaper GPS modules can track satellites indoors. Any experience feedback with these would be greatly appreciated.
  5. Something I’m missing? Everything else I thought of wouldn’t work because of the players interferring, but I’m a long way from being an old hand at this stuff.

Any thoughts are anxiously welcomed and greatly appreciated! Thanks!

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None of options 1-4 will work. Indoor localization is a difficult problem and accurate solutions tend to be expensive.

A cheap overhead camera, like the Arduino compatible Pixy2, can track an IR beacon or colored marker and report location.

Another option is to use DW1000 UWB beacons (at least 3 on the corners of the arena, and a tag on the dummy, which will report its (X,Y) position.

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Perfect accuracy here is not necessary. I just need to know they’ve moved enough away from the starting point to drop the effect of radiation damage. The game is won when the dummy is physically dragged to a zone, but the effect does not need to correspond exactly. If the effect were to gradually decrease until they were even halfway back, that would likely be sufficient. The triangulation method you suggest sounds like the JARVAS system that someone recommended to me. While this does sound like the most accurate, it also sounds like the most complex to set up, calibrate, and use quickly.

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The JARVAS system is one of several different methods that have been implemented using DW1000 beacons. Positional accuracy is around +/- 10 cm at best.

I just need to know they’ve moved enough away from the starting point to drop the effect of radiation damage.

Consider putting some numbers into that requirement. Distances can be measured between two DW1000 modules, also with about +/- 10 cm uncertainty.

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I don’t get it.
Are you building a dummy (heavy, cumbersome) to drag around?
But it’s not a dummy, it’s a geiger counter (portable, wearable)?
Also, there are several?

Is it important to know where the McGuffin is?
Isn’t this a simple finish line problem?

I half jokingly wonder whether you can’t you just handcuff a key to a weighted dummy to deactivate the launch timer or whatever?

In case you’re auditioning for the weighted dummy scientist part, I think I bring a lot to the table.

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Are you suitably heavy and cumbersome to drag around? :wink:

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No. The rescue game already exists. Players fight their way into a room where a life-sized, 80 pound rescue dummy is placed, and their job is to drag the dummy back to their spawn point. I’m being asked to add the radiation effect as a varation on the game. The geiger counter idea was just my first thought of a way to disguise a unit that was tracking roughly how far it had moved from the starting point, and decrease the effect of the radiation accordingly.

There is a simple finish line for the game. The dummy has to cross it. It doesn’t really have anything to do with the radiation, though. Maybe all I need to do is place IR emitters inside the room, and only damage the players in the room where the dummy is. Once they get the dummy out of there, the danger is removed. It would work just the same, and eliminate the need for tracking the movement.