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Topic: 361 sensors (Read 1 time) previous topic - next topic

Nova deViator

hi there!

sorry if this is a very general question, i thought somebody with good knowledge will point me in the right direction.

i want to read data from 361 sensors under a GO-game board back to the computer. i'm not even sure what sensors to use to be able to read black or white stones put on the crossings on the 19x19 grid, but i'm looking for any ideas how to go about this. is arduino a possibility? how many arduinos can one use on a single computer? as many as USB ports one has? i was looking at illuminato with 42 digital I/O (+6 analogue), but this would still take 8 of them. any had a similarly sized project before and would like to share any solutions?


retrolefty

With external shift registers, ICs, the 361 inputs would not be such a problem and no micro chip will have that many inputs standard anyway. The biggest hurdle will be the sensor design itself. Not only does it have to sense a piece being present on a square but which of two two colors it might be. May have to place something into the stones themselves?

This will take some creative thinking and most likely a fat wallet also  ;)

Lefty

Nova deViator

#2
Mar 06, 2009, 10:08 pm Last Edit: Mar 06, 2009, 10:08 pm by novadeviator Reason: 1
hi!

thanks for reply retrolefty. i think i will have to do some reading on shift registers, but as i understand at the moment it's a way to read multiple sensors into single input?

i discovered "reflectance sensor that carries a single infrared LED and phototransistor pair in an inexpensive, tiny 0.5" x 0.3" module" at polulu [http://www.pololu.com/catalog/product/959]. maybe this could work out, althouth 361 of them is quite a lot. it kills about half of my budget.

macegr

#3
Mar 06, 2009, 10:18 pm Last Edit: Mar 06, 2009, 10:21 pm by macegr Reason: 1
That sensor requires an actual I/O line, and accurate timing of the capacitor discharge once you switch to input mode. It's very unlikely you could successfully control those with shift registers.

Additionally, it's infrared. Your black or white stone might look the same in terms of infrared reflectance.
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retrolefty

Yes, you would read in a serial bit stream from the shift registers that would represent the state of all the squares into a signle input pin on the microprocessor and then store them into an array in your software program.

That sensor you show might not be any good at discriminating between colors just the presence of a stone or not and the size doesn't look to compatable with the large number of squares you have to sense. I'm not sure what would work on a budget basis.

Lefty

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