Advice on a "matrix sensor"!

Other Hardware Sensors
1

Hello forum,

I am after some advices / guidance / suggestions. I am planning a project that uses a search space (in the physical world this is a meter square piece of wood with a rim) and numerous small automated object (something like a slow hexbug) that will be running round the search space. I want to be able pot the position of these objects at any given time. For this I am going to need some way of creating a matrix sensor for positioning and also a way for the object to identify it's as being the one at that position.

I did think of something NFC based, where the object has a tag that contains ID info, when the object runs over a reader, the tag transmits its ID. As all the sensor are in known positions, when a read takes place, I will know where and by what object.

However, the will mean a lot of NFC readers to get any sort of accuracy and I do not think its a feasible way of working...

Thus, I am asking you guy if you have any ideas...

Thanking you in advance,
Harold Clements

2

You have a 1 metre square area but how many matrix points do you need in this area?

Maybe using IR receivers set into the play area and each hexbug has a downward facing IR transmitter sending a different IR code.

Use an overhead camera on the pay area connected to a PC and some open source object tracking software. Put a different colour/pattern on each hexbot and allow the camera to track position.

3

+1 on the camera as the most likely solution.

Should be lots of good examples online of this using RPi.

You could also place an IR Led on each unit, which could help with recognition (but not neccessary). The IR LEd would appear as a white spot on the camera. You could filter everything else out using an IR filter on the lens (old exposed film) or in s/w.