Post by thread:[PIC] Sensors request for info

>From my privious posts, you can all tell I'm a newbie. But as I anxious wait for my new Pickit2 burner and shipment of a couple different PIC's from Microchip I'm starting to think of projects. So my question is, how many and what kind of environmental sensors are PIC friendly? Like making a weather box. Check temp, humidity, temperature, whatever. On my second and most important project. Are there any "pressure sensors" that can be used with Pics? I'd really like to make a Chess board that could detect piece movement and feed that into the computer for computer-vs-human games. From a software point of view it's pretty simple. As long as I can get x/y coordinate from a grid I'm ok, then send the resulting x,y coordinates back. Figure I'll have LED's on x,y for the board. Then sensors along X and Y for input. Just need to know what kind of sensors I can use. Not as nice as pressure sensitive for all 64 squares. But capturing file/rank is enough for a starter project :) Any tips? Anyone do something similiar? --Josh

For the pressure sensors, there are many that are 3 wires (ground, +5vdc, and signal out) with the signal out at 0 -5 VDC which matches the PIC's typical ADC 0 -5 VDC input. Just quickly looking at Digikey, I find some typical part numbers.: 356-1042-ND 356-1036-ND Typically several small filter capacitors are required, but other wise just hook the sensor directly. There are many other manufacturer's, just go to the web page and search for pressure sensor, 5 volt output, and your pressure range. There are ones that get down to the range of barometers and altimeters. The other 2 routes are 1: a sensor with out built in OP-AMP where you add the external OP-AMP, and 2: The single wire connected to a serial port, but simplest is the direct connection. Joshua Shriver wrote: {Quote hidden}> >From my privious posts, you can all tell I'm a newbie. But as I anxious wait > for my new Pickit2 burner and shipment of a couple different PIC's from > Microchip I'm starting to think of projects. > > So my question is, how many and what kind of environmental sensors are PIC > friendly? Like making a weather box. Check temp, humidity, temperature, > whatever. > > On my second and most important project. Are there any "pressure sensors" > that can be used with Pics? I'd really like to make a Chess board that could > detect piece movement and feed that into the computer for computer-vs-human > games. From a software point of view it's pretty simple. As long as I can > get x/y coordinate from a grid I'm ok, then send the resulting x,y > coordinates back. Figure I'll have LED's on x,y for the board. Then sensors > along X and Y for input. Just need to know what kind of sensors I can use. > Not as nice as pressure sensitive for all 64 squares. But capturing > file/rank is enough for a starter project :) > > Any tips? Anyone do something similiar? > --Josh >

Joshua Shriver wrote: {Quote hidden}>>From my privious posts, you can all tell I'm a newbie. But as I anxious wait >for my new Pickit2 burner and shipment of a couple different PIC's from >Microchip I'm starting to think of projects. > >So my question is, how many and what kind of environmental sensors are PIC >friendly? Like making a weather box. Check temp, humidity, temperature, >whatever. > >On my second and most important project. Are there any "pressure sensors" >that can be used with Pics? I'd really like to make a Chess board that could >detect piece movement and feed that into the computer for computer-vs-human >games. From a software point of view it's pretty simple. As long as I can >get x/y coordinate from a grid I'm ok, then send the resulting x,y >coordinates back. Figure I'll have LED's on x,y for the board. Then sensors >along X and Y for input. Just need to know what kind of sensors I can use. >Not as nice as pressure sensitive for all 64 squares. But capturing >file/rank is enough for a starter project :) > >Any tips? Anyone do something similiar? >--Josh > > Search the piclist. Several years ago (at least 2) they had a discussion on just such a project. Being able to know which chess peice was where on the board. Recon

Joshua Shriver wrote: {Quote hidden}> >From my privious posts, you can all tell I'm a newbie. But as I anxious wait > for my new Pickit2 burner and shipment of a couple different PIC's from > Microchip I'm starting to think of projects. > > So my question is, how many and what kind of environmental sensors are PIC > friendly? Like making a weather box. Check temp, humidity, temperature, > whatever. > > On my second and most important project. Are there any "pressure sensors" > that can be used with Pics? I'd really like to make a Chess board that could > detect piece movement and feed that into the computer for computer-vs-human > games. From a software point of view it's pretty simple. As long as I can > get x/y coordinate from a grid I'm ok, then send the resulting x,y > coordinates back. Figure I'll have LED's on x,y for the board. Then sensors > along X and Y for input. Just need to know what kind of sensors I can use. > Not as nice as pressure sensitive for all 64 squares. But capturing > file/rank is enough for a starter project :) > > Any tips? Anyone do something similiar? > --Josh > I know just the ticket for that application. Use reflective IR emitter/receivers at each chess square. Each chess piece would have a reflective bottom. When the piece is removed from the board it is sensed, then when it is placed it is sensed again. From that, it is easy to deduct what is happening on the board. Digikey sells these devices, they need only a small hole about 3/16" in size. --Bob A

How 'bout a small magnet in each base and hall sensor or cheap reed switch at each position. No holes... AND, a thin steel strip on the side will hold the captured pieces in one place. Bob Axtell wrote: {Quote hidden}> Joshua Shriver wrote: > I know just the ticket for that application. > > Use reflective IR emitter/receivers at each chess square. Each chess > piece would have a reflective bottom. > When the piece is removed from the board it is sensed, then when it is > placed it is sensed again. From that, > it is easy to deduct what is happening on the board. > > Digikey sells these devices, they need only a small hole about 3/16" in > size. > > --Bob A

>> On my second and most important project. Are there any >> "pressure sensors" >> that can be used with Pics? I'd really like to make a >> Chess board that could .. >> Not as nice as pressure sensitive for all 64 squares. But >> capturing >> file/rank is enough for a starter project :) Hall sensors under each square and magnets in the pieces. RFID in each piece. Excite detectors one square at a time (maybe by row / column powering and read each piece absolutely. A version of this *could* be reasonably cheap. Place excitation coil under each square row column addressed. Each piece has a transmitter in it. Could be RF, acoustic even IR. Selected piece declares its ID to probably a single receiver. Could have resonant coils in each piece and tune across range per square till resonance found. Russell

Dr Skip wrote: {Quote hidden}> How 'bout a small magnet in each base and hall sensor or cheap reed switch at > each position. No holes... AND, a thin steel strip on the side will hold the > captured pieces in one place. > > > Bob Axtell wrote: > >> Joshua Shriver wrote: >> I know just the ticket for that application. >> >> Use reflective IR emitter/receivers at each chess square. Each chess >> piece would have a reflective bottom. >> When the piece is removed from the board it is sensed, then when it is >> placed it is sensed again. From that, >> it is easy to deduct what is happening on the board. >> >> Digikey sells these devices, they need only a small hole about 3/16" in >> size. >> >> --Bob A >> These are even better! Halls use a lot of current, but its only 64 places... --Bob

> RFID in each piece. > Excite detectors one square at a time (maybe by row / column > powering and read each piece absolutely. You don't need anything that complicated. The pieces have fixed starting points. Any piece that is lifted has only a few legal destinations. Castling is the only time things get even slightly interesting. Squak if someone puts a piece down where it can't legally get to.

>> RFID in each piece. >> Excite detectors one square at a time (maybe by row / >> column >> powering and read each piece absolutely. > You don't need anything that complicated. > The pieces have fixed starting points. > Any piece that is lifted has only a few legal > destinations. > Castling is the only time things get even slightly > interesting. > Squak if someone puts a piece down where it can't legally > get to. I agree that you don't NEED absolute position detection if everything works "by the rules". And my suggested Hall effect system works at that level. But it would be "nice" if one could handle real life rather than demanding that actions suit your limited reality. If you ever knock over a piece (let alone pieces) or nudge one enough off its square to create an anomalous situation, then something which detects piece position absolutely would be useful. Also, alas, more expensive and complex. Russell

> On my second and most important project. Are there any "pressure sensors" > that can be used with Pics? I'd really like to make a Chess board that > could > detect piece movement and feed that into the computer for > computer-vs-human > games. Rather than pressure sensor I would be tempted to use capacitance sensors. Microchip have a series of app notes on using a PIC for this, for keyboard sensing. With chess pieces I would look at putting a metal shim in the base to make a capacitance bridge. Another technique is to use a transformer sensor. I have somewhere a copy of an HP Journal where they did this for a keyboard, with each transformer being a 2 turn primary and 2 turn secondary as PCB etch. The key had a metal pad on the bottom that acted as a shorted turn when the key was pressed. It didn't actually contact the PCB, just came close enough to affect the transformer action.

Alan Pearce wrote: >I have somewhere a copy of >an HP Journal where they did this for a keyboard As an aside, HP Journals are available on line as .PDFs here: http://www.hpl.hp.com/hpjournal/journal.html Be patient as the download rate is slooow! Vic -- *____________________________________________________________________________________________* *Victor Fraenckel KC2GUI victorf ATSIGN windreader DOT com** *

>Alan Pearce wrote: >>I have somewhere a copy of >>an HP Journal where they did this for a keyboard > >As an aside, HP Journals are available on line as .PDFs here: > > http://www.hpl.hp.com/hpjournal/journal.html > >Be patient as the download rate is slooow! Oh, wow - seventh heaven indeed. The downloads don't appear to be that slow, other sites I have been to are worse ... Somehow the description of the 1700 series scopes as 'Power Thrifty & Portable' doesn't seem to hack it now ... (May 1971). Ahh, the first description of HP-IB what eventually became IEEE-488. (Oct 1972). Further refinements described in Jan 1975. The first of the scientific pocket calculators - the HP-35 (June 1972) - ahh the nostalgia ...