Looking for a sheet that resists

[gaspode42]

Resistive Films

Have you thought of something like **broken link removed**?

 

[Sceadwian]

Let me echo DK at this point. Simple resistance sheeting will not work, it can't do 'multi touch'

 

[blueroomelectronics]

Let me echo DK at this point. Simple resistance sheeting will not work, it can't do 'multi touch'

Add to that identify what's placed on it.

 

[Sceadwian]

In order for something like this to work you'd have to use 'smart' pieces. But the play surface itself would have to be a complex grid of resistive branches to provide voltage refrence for X/Y position and a grid of simple conductors to provide the pieces with power (batteries would be stupid)

I have a computerized chess set, it takes a MUCH simpler approach. Each 'square' is a simple membrane type touch sheet. You press the piece you want to move down, pick it up and press it down on the new square, works great. It 'knows' what piece is being moved by the initial starting conditions and has a method to set up pre-set conditions

 

[jasonbe]

Add to that identify what's placed on it.

Could the location of pieces be identified by how much uniquely spaced conductors on the bases of the pieces uniquely reduced the resistance in the sheet between multiple locations on the sheet, and the location of the pieces be identified by how a circuit in the game pieces incorporating these bases and the sheet were closed at distinct intervals producing unique contributions to fluctuations in one of the electrical connections to the sheet?

 

[jasonbe]

Have you thought of something like **broken link removed**?

Would the amount of heat produced and resistance vary if I decreased the spacing of the connections?

 

[jasonbe]

In order for something like this to work you'd have to use 'smart' pieces. But the play surface itself would have to be a complex grid of resistive branches to provide voltage refrence for X/Y position and a grid of simple conductors to provide the pieces with power (batteries would be stupid)

I have a computerized chess set, it takes a MUCH simpler approach. Each 'square' is a simple membrane type touch sheet. You press the piece you want to move down, pick it up and press it down on the new square, works great. It 'knows' what piece is being moved by the initial starting conditions and has a method to set up pre-set conditions

I couldn’t think of a neat way to identify enough locations by modifying a keyboard to implement a device similar to your chess game. I also wasn’t able to encode signals in a grid with resistive values having a high place values representing distances in one direction and resistive values having low place values in another direction because I haven’t come across resistors with a tolerance that would allow this.

 

[tcmtech]

Simple X - Y conductive grid lines with each piece having its own unique resistance signature.
At each grid wire crossing a simple non conductive film is placed between them.
By measuring the circuit voltage of each grid line on each axis one at a time a map can be made of whats siting where. Common touch screen mapping technique from way back.
Just add the variable resistance factor in to know what is where.
It will take a micro processor to do the mapping and grid line switching and voltage measuring but it will give what you need.

Think of it as a dot matrix light system only back wards. Instead of telling what row and column and what intensity to put out, you measure rows and columns and what resistance is found at what point.

 

[Sceadwian]

The X/Y conductive grid lines are the hard part. good idea for the piece having unique resistance, can let them be a binary sequence. You'd need 32 bit accuracy for a chess set though...

 

[tcmtech]

As far as grid based games go tick-tack-toe is about as complicated as I get!

I can do checkers but not well!

Chess? WTF?

 

[crashsite]

There are ways and then there are ways...

Did you learn about graphite from a list?

Uhmmmm...I kind of "learned" about graphite making carbon arc lamps using #1 pencil lead as the carbon rods. Fun but, not overly practical.

Depending on the level of sophistication you are willing to deal with (assuming that you are indeed serious about actually building your project), you might want to start with a digitizing tablet. They've not only figured out the X-Y positioning, they also have a pressure sensor in their stylus.

FRYS.com*|*Aiptek

Usually, they have a clear overlay that allows you to put stuff you want to trace under.

You'd have to find out what the implications are of using multiple pieces at once (if that's needed for your game) but, I'm sure there would be ways to code the pieces to avoid interaction. You know, sort of like being able to connect many USB devices to a computer and having them sorted out and operated independently even when they are connected to random USB ports.

Again, I have to question if you're both serious about doing this and if you have the skills...or if you just got a wild notion that you are trying to figure out. If your intention is to actually try to build it, at some point you really do need to stop picking people's brains and gather up some parts and do some experimenting. There's actually quite a lot you can try with simple, home-made and inexpensive components and parts.

Just a thought. I wonder if a triangular sheet might actually allow you to "triangulate" a position by sensing the resistances from the game piece relative to the "corners". Or maybe if the measurement, on a square sheet, could be multiplexed to alternately measure the resistance up and down and then left to right so that you might calculate the position.

The point is, that there are ways to apprach this (including pooh-poohing it) and, while it's not something I'm tempted to do at this time, is not an uninteresting idea.

 

[Rolf]

Are there thin sheets of material on the market that have resistance levels - comparable to resistors, which vary in a well defined relation to units of distance?

This might help:
can i make detectable whlsets with resistance paint

 

[jasonbe]

The X/Y conductive grid lines are the hard part. good idea for the piece having unique resistance, can let them be a binary sequence. You'd need 32 bit accuracy for a chess set though...

Would variable resistors work for this? Is there a less expensive form of resistance?

 

[jasonbe]

Simple X - Y conductive grid lines with each piece having its own unique resistance signature.
At each grid wire crossing a simple non conductive film is placed between them.
By measuring the circuit voltage of each grid line on each axis one at a time a map can be made of whats siting where. Common touch screen mapping technique from way back.
Just add the variable resistance factor in to know what is where.
It will take a micro processor to do the mapping and grid line switching and voltage measuring but it will give what you need.

Think of it as a dot matrix light system only back wards. Instead of telling what row and column and what intensity to put out, you measure rows and columns and what resistance is found at what point.

What type of materials would you recommend for the grid with films? I started making something that began to look as difficult to make as a loom.

 

[tcmtech]

Smallest copper wire you can find and clear tape!


Lay out your grid without the tape and then roll it smooth with a big roller and steel plate if possible. That will flatten out the points where the wires intersect. Then reassemble with the tape so that the crossing points dont conduct to each other.

Its just a theoretical idea though.

 

[jasonbe]

Uhmmmm...I kind of "learned" about graphite making carbon arc lamps using #1 pencil lead as the carbon rods. Fun but, not overly practical.

Depending on the level of sophistication you are willing to deal with (assuming that you are indeed serious about actually building your project), you might want to start with a digitizing tablet. They've not only figured out the X-Y positioning, they also have a pressure sensor in their stylus.

FRYS.com*|*Aiptek

Usually, they have a clear overlay that allows you to put stuff you want to trace under.

You'd have to find out what the implications are of using multiple pieces at once (if that's needed for your game) but, I'm sure there would be ways to code the pieces to avoid interaction. You know, sort of like being able to connect many USB devices to a computer and having them sorted out and operated independently even when they are connected to random USB ports.

Again, I have to question if you're both serious about doing this and if you have the skills...or if you just got a wild notion that you are trying to figure out. If your intention is to actually try to build it, at some point you really do need to stop picking people's brains and gather up some parts and do some experimenting. There's actually quite a lot you can try with simple, home-made and inexpensive components and parts.

Just a thought. I wonder if a triangular sheet might actually allow you to "triangulate" a position by sensing the resistances from the game piece relative to the "corners". Or maybe if the measurement, on a square sheet, could be multiplexed to alternately measure the resistance up and down and then left to right so that you might calculate the position.

The point is, that there are ways to apprach this (including pooh-poohing it) and, while it's not something I'm tempted to do at this time, is not an uninteresting idea.

I haven’t found a balance between prices and neatness. Perhaps this topic belongs more in the electronic theory rather than projects section of this site. However, while comparing the sensitivity of alternating and direct current to changes in distance and time, resistive materials, non-resistive closed circuits having predetermined lengths, and the edges of materials is something that I don’t know a lot about, it is interesting to me. Were you thinking that a triangular sheet might be a useful alternative to a square sheet because of the way that electricity might react to the edges of the sheet? I don’t even know if this would be avoidable with a triangular sheet. Would the electricity have to be introduced at the same time to all of the locations on both sides of a square sheet, and would this work? These are things that I think that might be good to know in advance in addition to experimenting with. The reason why I asked about the list was because I was experimenting with the idea of measuring resistance as a function of distance with direct current in two dimensions.

 

[jasonbe]

Smallest copper wire you can find and clear tape!


Lay out your grid without the tape and then roll it smooth with a big roller and steel plate if possible. That will flatten out the points where the wires intersect. Then reassemble with the tape so that the crossing points dont conduct to each other.

Its just a theoretical idea though.

I like the idea but unless the wires were spaced far apart – decreasing the precision with which the location of pieces could be measured to an unacceptable amount, I think that participants would have to be overly precautions about where they placed the pieces to avoid the insulating tape.

 

[tcmtech]

SO what exactly is this thing your making and how small are the playing pieces?

If things get to small human dexterity can get to be a problem. With under inch square spacing pick and place can get difficult for complex games.

Look at standard checkers or chess boards there is a reason they keep the spaces typically rather large.
Us bigger built German/Scandinavian/Russian folks have index finger widths around 3/4 of an inch and thumbs around an inch!

We dont like tiny toys! Cell phones, car radios, TV remotes. ugh.. to small of buttons to close together.

At a certain level of complexity optical scanning and bar code recognition may become a more practical method of sensing.

 

[jasonbe]

SO what exactly is this thing your making and how small are the playing pieces?

If things get to small human dexterity can get to be a problem. With under inch square spacing pick and place can get difficult for complex games.

Look at standard checkers or chess boards there is a reason they keep the spaces typically rather large.
Us bigger built German/Scandinavian/Russian folks have index finger widths around 3/4 of an inch and thumbs around an inch!

We dont like tiny toys! Cell phones, car radios, TV remotes. ugh.. to small of buttons to close together.

At a certain level of complexity optical scanning and bar code recognition may become a more practical method of sensing.

The game is generalized so as to be able to represent a variety of land and sea formations and statuses of game pieces. I haven’t thought of any reason why the size of the game pieces would have to be related to the size of the conductors on the base of the pieces. A more precise continuous representation of locations – rather than discrete representations, is preferable, however. I’m trying to figure out how to communicate information to and from the pieces without having wires run to the pieces separate from those connected to the sheet.

 

[crashsite]

Let's Get Physical...

The reason why I asked about the list was because I was experimenting with the idea of measuring resistance as a function of distance with direct current in two dimensions.

I can tell you, without fear of condradiction, that trying to do what you have in mind with "resistances" will lead to nothing but headaches. It's difficult enough to maintain variable resistances accurately in something as simple as a rheostat or potentiometer. Trying to do it on an open plane with manually placed game pieces will be a nightmare.

You really need to be thinking about something that will be more interactive between the playing field and the pieces. And, yes...that's a lot more sophisticated and complex.

Having said that, I reiterate: Gather up some parts and play around with your ideas. Don't expect to end up with a working system but, it will force you to face some of the problems people here have experienced in their own experimenting and can give you a good feel for what you can't do...and, if you're very lucky...maybe a few ideas of what you can do.

My recommendation for a first step is to get an Ohmmeter (analog if possible) and some graphite (grind up some #1 and #2 pencil lead) and some likely surfaces (paper, plastic, cardboard, wood, etc.). Smear some graphite on things and slide the Ohmmeter probes around on it and see how it all seems to work...or not work...