I can't think of anything I've seen that is similar to what you're trying to do. There are many applications for a cheap and simple solution so I would have thought if it was possible there would already be something like it out there.
Look at commercial electronic chess boards, an 8x8 matrix and simple magnets on the bottoms. The locations are tracked by computer.
A fancy (not cheap) chessboard would have RFID tags on each piece and an 8x8 antenna matrix for the board.
How big would your matrix be or how small could you tolerate it?

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com/

 

PS someone doing something similar for a chessboard. Resonating coils but still complex.
ChessCircle - How electronic chessboards works

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com/

 

the reason i sugested 2 perpendicular sets of wires insulated from each other is quite simple, if you imagine a grid made up of the resistive wires that had the x and y axis connected, you would have the same resistance at grid reference C2 as you would at grid reference B3 and so on, just draw a 5 line by 5 line grid and you will see what I mean.

With both x and y insulated, the further you get from your source point, the higher the resistance. Hope that you can follow my thinking on this method
Karl.

 

If, by matrix, you mean the dimensions of my game board, the dimensions are about 2 feet by two feet. I don’t think that making the type of position detection mechanism that I’m working on isn’t doable, I just think that making a McDonald’s or Wendy’s or Burger King version of the touch screen hasn’t been a priority for anyone. Though, by saying this, I’m making the assumption – possibly wrong, that a product that is easier to use is more difficult to synthesize materials for and build. With the materials available to me, the best design that I have thought of so far involves making or obtaining a structure resembling a large metal brush having a foundation resembling a square and densely spaced thin parallel metal spikes; electrically testing and connecting about 6 sheets of carbon paper whose level of resistance to electricity is sensitive, consistent, and measurable over the dimensions of a game board; piercing the carbon paper with the spikes on the metal brush-like structure so that an electrical connection is make between the carbon paper and the spikes; painting a side of a number of non-conducting square pieces of mesh having a large mesh number and a large gauge to resemble a number of game board designs; and placing just enough of each thin parallel metal spike through the bottom unpainted part of the mesh to make contact with any of the electrically conducting bottoms of the game pieces on the other, painted side of the mesh. However, this structure has many disadvantages including not being compact, not having an aesthetical game board appearance, and may not have a very consistent change in voltage per unit distance due to irregular spacing of the spikes on the metal brush-like structure.

 

Time for some perspective, first of all, what size of board are we looking at, next is how many individual grid squares, what size are the play pieces, and how many play pieces are there likely to be on the board at any one time.

I bet I have misssed something, but I am just trying to visualise what we are lookig at.


edit looks like we posted at the same time

 

I wonder if there is a manufacturer of screens who uses a non-conducting material to physically connect the wires of the screen running perpendicular directions.

 

New thought, what about a matrix of light dependant resistors? the position side is simple enough, and could you control the amount of light passing thru each play piece to determine it's identification, as the level of light changes the LDR resistance value?

 

The board is about two feet by two feet. If I have to use grid squares, then the number of grid squares that I plan on using would preferable be as many as possible – to more accurately identify latitude and longitude positions. I am also exploring ways of identifying positions on the game board as a continuous function of resistance, and would like to hear new ideas as well. The play pieces are about an inch – maybe a little more, in diameter. There are going to be about 5 play pieces on the surface at any given time. The game board does not have to resemble the description of a game board given in the Monday, December 01, 2008 08:01 PM post.

 

As I stated before, I can think of nothing like it on the market. Is there anything similar to your design?

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com/

 

Well, detection mechanisms, some of which have been mentioned in the posts that I have started, that don’t include aerial mechanisms – such as mechanisms that detect objects according to how sound or different types of electromagnetic waves reflect off of or are obscured by the objects that are being located, probably include flat objects that have some type of pressure, heat, or chemical detection system to identify locations. I suppose that a flat object could also have a sound or a light detection mechanism.

I don’t know of any pads, screens, or boards that generate output signals that indicate locations according to the location of an electronic connection made on the pad, screen, or board - as my design would. If there were such a design on the market then I might be able to use the same material - as the design on the market, to make my game board - if this material was available. I think that I’ll have better luck searching for the appropriate material to make my design - rather than searching for an example product on the market. This involves finding a database that includes the resistive properties - and maybe even the stiffness, of materials that are sold in sheets.

I suppose that it might be possible to detect an object on a flat speaker-like device by analyzing how much mechanical resistance an object placed on predefined locations on the device offered to an electromagnet that caused this device to vibrate. While this would free up the game pieces from having to have electrically conduction bottoms, the location of each game pieces might only be able to be narrowed down to the perimeter of a particular rounded shape on the device. Such a device with two or three electromagnets might work. I don’t know if there are speakers such as the device that I am describing on the market. If there are such speakers on the market, I doubt that they are as flat as I would like my game board to be. But, anyway, I would like to hear what such a speaker (would) sound(s) like.

 

So far, this thread has been about how to obtain products and materials. Anyone know about the structure of resistors, and other characteristics of electricity that may change as a function of distance through a sheet of material? How would the flow of electricity differ when travelling through a thin conducting cylinder such as a wire versus a conducting sheet? Would it be more accurate to describe the electricity as dispersing through a sheet rather than travelling through a wire?