Structure of resistor question

[jasonbe]

What is the structure of resistors that gives them their resistive properties? Do you know of any materials that are thin, flat, stiff, durable, and have consistent resistive properties? I’d like to be able to measure distances on such a piece of material about 2 feet by 2 feet as a function of resistance applied to 3-5 volts. So, the amount of resistance that the material offered would have to vary consistently as a function of distance from a point on the material where electricity would be connected. I’d also like to be able to represent hypothetical land formations on a game board using this material. So, the material might have to be transparent or mesh-like – so that the appearance of the game board design could be seen through the material. Do you know if there is a conductive paint that would allow electricity to flow from the material through the paint and into game pieces that I would like to use on the game board? The position each game piece could then be calculated, I think, as a function of the voltage drop between three points where electricity is connected to the material and the location of each game piece on the material.

 

[Willbe]

Search

telo

 

[microtexan]

structure of resistor

try a google search:

electrically conductive paint

 

[jasonbe]

Search

telo

In case you can get back to me before Monday – and you were talking about Telo Electronics, would you tell me who their distributors are? If you weren’t talking about this company, would you recommend some keywords for me to search with telo?

 

[jasonbe]

try a google search:

electrically conductive paint

Ever hear of this type of paint coming in colors besides silver, like green, blue, gray, and black?

 

[blueroomelectronics]

Well gold but that would be expensive.

It's not going to work as an X-Y gameboard for a few reasons, one is it's not going to be linear unless you somehow apply it perfectly.

 

[jasonbe]

Well gold but that would be expensive.

It's not going to work as an X-Y gameboard for a few reasons, one is it's not going to be linear unless you somehow apply it perfectly.

Really, I wouldn’t have thought that this type of paint is so resistive.

 

[jasonbe]

Does anyone know of a site where I could find a list of the resistive properties of materials, and maybe even the stiffness of these materials? I don’t know if resistive properties change according to the shape of the material being evaluated, but I am looking for a material whose resistance to about 3-5 volts varies consistently and significantly as a function of distance on a thin piece of material between very small distances – the smaller the better, and also distances as large as about 3 feet. Are there any other properties of electricity that change as a function of distance in thin materials that can help me expand my search for a material that I can use to measure distances electronically? The list has to include materials that are commercially available in thin, flat, stiff sheets that can be reduced in size to about 2 feet by 2 feet without specialized tools. Should I be searching for semiconductors or alloys? Someone helped me out earlier with the idea of carbon paper, but carbon has so many different forms. And I am looking for something a little more durable. Also, out of curiosity, and correct me if I’m wrong, but why is it that the conductive properties of chemicals increase toward the lower left of the periodic table; but gold, silver, and copper are to the right of the periodic table? Also, what are the chemical properties of the material that I am looking for?

 

[blueroomelectronics]

I can't think of anything that's simple / cheap that meets your requirements. Look at electronic chessboards. The use a 8x8 grid often with simple magnetic sensors and magnets on the piece bottoms.

How would you identify different pieces on your resistance grid? One piece would be simple but with two or more it wont work.

Complex but possible would be a grid of small coil antennas on the board switched on one at a time with RFID tags in the game pieces.

 

[JKF1000]

What about a matrix of resistive wires, not as discrete as the paint method, but if you setup a grid of X and Y axis, with the values of each axis monitored individualy,and insulated from each other, you should then be able to calculate positions on the board, asuming that your playing pieces have conductive bases. Karl.

 

[3v0]

Is it enough to know there is a piece at a location, or do you also need to know which piece is at what location ?

 

[JKF1000]

Now we are getting technical

 

[jasonbe]

I can't think of anything that's simple / cheap that meets your requirements. Look at electronic chessboards. The use a 8x8 grid often with simple magnetic sensors and magnets on the piece bottoms.

How would you identify different pieces on your resistance grid? One piece would be simple but with two or more it wont work.

Complex but possible would be a grid of small coil antennas on the board switched on one at a time with RFID tags in the game pieces.

Why don’t you think two or more pieces would work? While thinking about what you wrote in your post, I started trouble-shooting. One problem that I might run into is that the signals received by each game piece might interfere with the signals that the other game pieces receive, complicating the task of interpreting the location-identifying signals - and possibly making it so that each signal could not be interpreted as corresponding to only one location. This problem would have to be considered if, when the computer is not reading the microchip pins to which the game pieces are connected, the circuits to the pins that are not being read stay closed and interfere with a signal being read. One way around this problem would be to attach relays to pins that would open these circuits. Though, this solution would add the additional cost of relays and use up pins that could be used in other ways.

What did you mean by a grid of small coil antennas?

 

[jasonbe]

What about a matrix of resistive wires, not as discrete as the paint method, but if you setup a grid of X and Y axis, with the values of each axis monitored individualy,and insulated from each other, you should then be able to calculate positions on the board, asuming that your playing pieces have conductive bases. Karl.

Can you think of a way of doing this that would not involve insulating wires running perpendicular to each other in the X and Y directions?

 

[jasonbe]

Is it enough to know there is a piece at a location, or do you also need to know which piece is at what location ?

I need to know which piece is at which location. However, if you would tell me of a way of identifying locations without identifying pieces, it might help me think of some more ideas. I plan on keeping the voltage between about 3 and 5 volts. So, I can connect the electricity running through any of the game pieces to analog microchip pins having a maximum voltage of about 3 or 5 volts. Then, a computer could identify the game pieces by identifying which of the many microchip pins is receiving each location-specific signal.

 

[blueroomelectronics]

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?

 

[blueroomelectronics]

PS someone doing something similar for a chessboard. Resonating coils but still complex.
**broken link removed**

 

[JKF1000]

Can you think of a way of doing this that would not involve insulating wires running perpendicular to each other in the X and Y directions?

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.

 

[jasonbe]

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?

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.

 

[JKF1000]

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