Post by thread:[OT] PIC to Pressure Mats

Summary: looking for cheap sensor mats or alternatives. There's this team motivational game played on a canvas mat, marked with squares, six foot by nine foot, each square a foot wide. The facilitator holds a beeper and a secret paper map, and makes the beeper go when a player stands on a square that is marked on the map as bad. I want to see if I can improve it by adding a bit of automation. I'd thought of mass/pressure sensitive mats as used for shop doors. The only source I've found locally is for a door size, with no indication as to whether I can cut it up and still make it work. Do any of you know sources of such mats? I'd thought of a set of column and row lasers, but they would require alignment every time. I'd thought of the player carrying a metal target strapped to the shoes and somehow using inductive sensing in the mat, but I'm afraid I'm a bit clueless on that. Any ideas? The area is a touch small for using differential GPS, but can one do something similar with low power UHF? The mat has to be reasonably portable and robust, as it is carried to training classes by the facilitator. Interface to the PIC will be by a matrix. Due to the nature of the game rules; (a) only one person on the mat at any time, (b) must move to square immediately next to current square (chess: king move), (c) must enter or leave the mat by the top or bottom edge; the matrix can be multiplied into six instances of three by three, thus utilising only six lines on the PIC. The rest of the game simulation intelligence would be on a laptop interfaced by serial port to the PIC. The PIC would be the data gatherer. -- James Cameron (spam_OUTquozlTakeThisOuTus.netrek.org) Linux, Firewalls, OpenVMS, Software Engineering, CGI, HTTP, X, C, FORTH, COBOL, BASIC, DCL, csh, bash, ksh, sh, Electronics, Microcontrollers, Disability Engineering, Netrek, Bicycles, Pedant, Farming, Home Control, Remote Area Power, Greek Scholar, Tenor Vocalist, Church Sound, Husband. "Specialisation is for insects." -- Robert Heinlein.

{Quote hidden}> Summary: looking for cheap sensor mats or alternatives. > > There's this team motivational game played on a canvas mat, marked with > squares, six foot by nine foot, each square a foot wide. The > facilitator holds a beeper and a secret paper map, and makes the beeper > go when a player stands on a square that is marked on the map as bad. > > I want to see if I can improve it by adding a bit of automation. > > I'd thought of mass/pressure sensitive mats as used for shop doors. The > only source I've found locally is for a door size, with no indication as > to whether I can cut it up and still make it work. Do any of you know > sources of such mats? > > I'd thought of a set of column and row lasers, but they would require > alignment every time. I'd thought of the player carrying a metal target > strapped to the shoes and somehow using inductive sensing in the mat, > but I'm afraid I'm a bit clueless on that. Any ideas? > > The area is a touch small for using differential GPS, but can one do > something similar with low power UHF? > > The mat has to be reasonably portable and robust, as it is carried to > training classes by the facilitator. > > Interface to the PIC will be by a matrix. Due to the nature of the game > rules; (a) only one person on the mat at any time, (b) must move to > square immediately next to current square (chess: king move), (c) must > enter or leave the mat by the top or bottom edge; the matrix can be > multiplied into six instances of three by three, thus utilising only six > lines on the PIC. > > The rest of the game simulation intelligence would be on a laptop > interfaced by serial port to the PIC. The PIC would be the data > gatherer. > > -- > James Cameron (.....quozlKILLspam@spam@us.netrek.org) > Check out Piezo Co-Polymer sensors or "Kynar" made by AMP. They come in a wide variety of shapes but most start out in sheet form, looks and feels like mylar film with printed electrodes on it. Those silly shoes that flash a led whenever one takes a step uses these sensors, as does Gottlieb PinBall Machines to sense a contact, good for millions of operations and fairly cheap. The only limitation is that they are piezo electric and as such look like a capacitor in series with a battery, they only sense a change, cant see that as too much of a problem though. We have used these sensors to make Hydrophones (in cylindrical form) and impact sensors. A 2 cm deviation can generate 100 volts in these sensors... very sensitive. Lance

Talk to an Alarm supply store. There is a "Intrusion mat" which you can by for use in burglar alarms, which measures approx 40cm by 60 cm This would be more up your alley, OR>>>>> make it yourself. To make it yourself, you will need plywood (2 squares) with locating holes drilled in each corner. then drill several holes through out the ply so it resembles "peg board". then weave a light guage wire through these holes to make up a grid on ONE side of the plywood sheet. (repeat for other sheet) Then using small "squares" of foam rubber (or styrofoam) build a "sandwich" of ply - foam - ply with the wire grids facing each other. then use "reopenable" cable ties in each "locator hole" to ensure the boards can't shift around and you have a pressure switch mat which will be about 20mm (3/4") thick. The reasoning of why I specified "reopenable cable ties" is so you can easily open the switch to replace the little foam squares once they wear down and stop acting as springs. For an "asthetically pleasing appearance" I'd then make up a small "zip up" cover for the switch (viz a cushion cover) so the ply is covered. Does this help? Des Bromilow >>> James Cameron <quozlKILLspamUS.NETREK.ORG> 6/16/99 8:24:03 am >>> Summary: looking for cheap sensor mats or alternatives. There's this team motivational game played on a canvas mat, marked with squares, six foot by nine foot, each square a foot wide. The facilitator holds a beeper and a secret paper map, and makes the beeper go when a player stands on a square that is marked on the map as bad. I want to see if I can improve it by adding a bit of automation. I'd thought of mass/pressure sensitive mats as used for shop doors. The only source I've found locally is for a door size, with no indication as to whether I can cut it up and still make it work. Do any of you know sources of such mats? I'd thought of a set of column and row lasers, but they would require alignment every time. I'd thought of the player carrying a metal target strapped to the shoes and somehow using inductive sensing in the mat, but I'm afraid I'm a bit clueless on that. Any ideas? The area is a touch small for using differential GPS, but can one do something similar with low power UHF? The mat has to be reasonably portable and robust, as it is carried to training classes by the facilitator. Interface to the PIC will be by a matrix. Due to the nature of the game rules; (a) only one person on the mat at any time, (b) must move to square immediately next to current square (chess: king move), (c) must enter or leave the mat by the top or bottom edge; the matrix can be multiplied into six instances of three by three, thus utilising only six lines on the PIC. The rest of the game simulation intelligence would be on a laptop interfaced by serial port to the PIC. The PIC would be the data gatherer. -- James Cameron (.....quozlKILLspam.....us.netrek.org) Linux, Firewalls, OpenVMS, Software Engineering, CGI, HTTP, X, C, FORTH, COBOL, BASIC, DCL, csh, bash, ksh, sh, Electronics, Microcontrollers, Disability Engineering, Netrek, Bicycles, Pedant, Farming, Home Control, Remote Area Power, Greek Scholar, Tenor Vocalist, Church Sound, Husband. "Specialisation is for insects." -- Robert Heinlein.

Check out http://www.qprox.com. They sell one chip proximity sensors. You might be able to embed a sensor wire in the square and detect when someone steps in it. Eric {Quote hidden}> > >>> James Cameron <EraseMEquozlspam_OUTTakeThisOuTUS.NETREK.ORG> 6/16/99 8:24:03 am >>> > Summary: looking for cheap sensor mats or alternatives. > > There's this team motivational game played on a canvas mat, marked with > squares, six foot by nine foot, each square a foot wide. The > facilitator holds a beeper and a secret paper map, and makes the beeper > go when a player stands on a square that is marked on the map as bad. > > I want to see if I can improve it by adding a bit of automation. > > I'd thought of mass/pressure sensitive mats as used for shop doors. The > only source I've found locally is for a door size, with no indication as > to whether I can cut it up and still make it work. Do any of you know > sources of such mats? > > I'd thought of a set of column and row lasers, but they would require > alignment every time. I'd thought of the player carrying a metal target > strapped to the shoes and somehow using inductive sensing in the mat, > but I'm afraid I'm a bit clueless on that. Any ideas? > > The area is a touch small for using differential GPS, but can one do > something similar with low power UHF? > > The mat has to be reasonably portable and robust, as it is carried to > training classes by the facilitator. > > Interface to the PIC will be by a matrix. Due to the nature of the game > rules; (a) only one person on the mat at any time, (b) must move to > square immediately next to current square (chess: king move), (c) must > enter or leave the mat by the top or bottom edge; the matrix can be > multiplied into six instances of three by three, thus utilising only six > lines on the PIC. > > The rest of the game simulation intelligence would be on a laptop > interfaced by serial port to the PIC. The PIC would be the data > gatherer. > > -- > James Cameron (quozlspam_OUTus.netrek.org) > > Linux, Firewalls, OpenVMS, Software Engineering, CGI, HTTP, X, C, FORTH, > COBOL, BASIC, DCL, csh, bash, ksh, sh, Electronics, Microcontrollers, > Disability Engineering, Netrek, Bicycles, Pedant, Farming, Home Control, > Remote Area Power, Greek Scholar, Tenor Vocalist, Church Sound, Husband. > > "Specialisation is for insects." -- Robert Heinlein.

Possibly, you could try their QT60320 Matrix Scanning IC, this sounds maybe IDEAL for that job. (See http://interquant.com/qt60320ic.htm) I don't have a .PDF file yet - they're nice folks from my talking to them so far, and their circuit looks decent. Also look at the QT9701 (Ask them - they know their line well, Technical Sales folks not salespeople from what I gather <G>) Their QT110 might do it ($1.95 ea in quantity), I have samples but need to get around to 'em still. (Looking forward to that!) Tons of other ways to do this, of course - If it works, it's good <G> Mark Eric Oliver wrote: {Quote hidden}> > Check out http://www.qprox.com. They sell one chip proximity sensors. You might > be able to embed a sensor wire in the square and detect when someone steps > in it. > > Eric > > > > > >>> James Cameron <@spam@quozlKILLspamUS.NETREK.ORG> 6/16/99 8:24:03 am >>> > > Summary: looking for cheap sensor mats or alternatives. > > > > There's this team motivational game played on a canvas mat, marked with > > squares, six foot by nine foot, each square a foot wide. The > > facilitator holds a beeper and a secret paper map, and makes the beeper > > go when a player stands on a square that is marked on the map as bad. > > > > I want to see if I can improve it by adding a bit of automation. > > > > I'd thought of mass/pressure sensitive mats as used for shop doors. The > > only source I've found locally is for a door size, with no indication as > > to whether I can cut it up and still make it work. Do any of you know > > sources of such mats? > > > > I'd thought of a set of column and row lasers, but they would require > > alignment every time. I'd thought of the player carrying a metal target > > strapped to the shoes and somehow using inductive sensing in the mat, > > but I'm afraid I'm a bit clueless on that. Any ideas? > > > > The area is a touch small for using differential GPS, but can one do > > something similar with low power UHF? > > > > The mat has to be reasonably portable and robust, as it is carried to > > training classes by the facilitator. > > > > Interface to the PIC will be by a matrix. Due to the nature of the game > > rules; (a) only one person on the mat at any time, (b) must move to > > square immediately next to current square (chess: king move), (c) must > > enter or leave the mat by the top or bottom edge; the matrix can be > > multiplied into six instances of three by three, thus utilising only six > > lines on the PIC. > > > > The rest of the game simulation intelligence would be on a laptop > > interfaced by serial port to the PIC. The PIC would be the data > > gatherer. > > > > -- > > James Cameron (KILLspamquozlKILLspamus.netrek.org) > > > > Linux, Firewalls, OpenVMS, Software Engineering, CGI, HTTP, X, C, FORTH, > > COBOL, BASIC, DCL, csh, bash, ksh, sh, Electronics, Microcontrollers, > > Disability Engineering, Netrek, Bicycles, Pedant, Farming, Home Control, > > Remote Area Power, Greek Scholar, Tenor Vocalist, Church Sound, Husband. > > > > "Specialisation is for insects." -- Robert Heinlein.

Jameco all sells a flex sensor. It doesn't say how long it is, but it might coul d be placed diagonally in the square. On Tuesday, June 15, 1999 8:03 PM, William Chops Westfield [SMTP:RemoveMEbillwTakeThisOuTCISCO.COM ] wrote: {Quote hidden}> >> To make it yourself, [horrific sounding construction details] > > I think you'd be better off finding a bunch of the conductive foam that IC > chips are stuck in for shipping samples, or some of the conductive work mats > or floor tiles designed for antistatic environments. They ought to change > resistance depending on how much weight is on them... Not particularly > CHEAP, IIRC, but likely to hold up much better. > > BillW >

James Cameron wrote: > Summary: looking for cheap sensor mats or alternatives. > and makes the beeper go when a player stands on a square that is > marked on the map as bad. I'd go for the proximity sensors. The Qprox or similar ones sound fine, but you have to get them (here!). I very much suspect (am banking on it in fact) that a PIC will do this very well, and I'd look at using one PIC at the intersection of each four squares (shortest connections - they are a problem, if shielded, extra capacitance, if not, spurious tripping). Sensors would be foil, probably under a plastic sheet to protect the connections as much as for electrical isolation. Protection resistors maybe 10 k ohm with diodes to supply rails etc. Another challenge in PCB protection. -- Cheers, Paul B.