M
mike diack
Guest
I need something like these for a conference -
cheers
Mike
cheers
Mike
M
Mark van der Eynden
Guest
moby@kcbbs.gen.middleearth (mike diack) wrote in message news:<40450095.10486170@News.xtra.co.nz>...
resistor in it that ens up getting paralleled with with the A, B, C or
D wire. The total resistance of each wire then shows how many people
are holding down each button.
Cheers,
Mark
Probably not as difficult as you think, say each box has a 100k
resistor in it that ens up getting paralleled with with the A, B, C or
D wire. The total resistance of each wire then shows how many people
are holding down each button.
Cheers,
Mark
M
mc
Guest
yeah good if they all press it at the same time ..but if they are out of
sequence even ms your parralel resistor theory will not work
it be more likely processor controlled polled @ certain times and
would have to be stored and checked again till all votes are in certain
time frame..otherwise you could get multiple votes from the same person ...
Mark van der Eynden wrote:
sequence even ms your parralel resistor theory will not work
it be more likely processor controlled polled @ certain times and
would have to be stored and checked again till all votes are in certain
time frame..otherwise you could get multiple votes from the same person ...
Mark van der Eynden wrote:
K
KLR
Guest
On Wed, 03 Mar 2004 15:02:25 +1100, mc <phmc@cc.newcastle.edu.au>
wrote:
units as well to "clear" all boxes once the vote has been taken.
When latched of course by a button press - it would lock out use of
the other 3 buttons (choices) on the same panel. A small relay could
easily be used to do this in a DIY project. Of course if you had
hundreds of such boxes, the combined currents of all these relays
could add up to a substantial amount
should be able to make the thing 2 or 3 wire quite easily then too and
massively cut installation costs.
wrote:
first button pressed - and have a master reset line running to all
units as well to "clear" all boxes once the vote has been taken.
When latched of course by a button press - it would lock out use of
the other 3 buttons (choices) on the same panel. A small relay could
easily be used to do this in a DIY project. Of course if you had
hundreds of such boxes, the combined currents of all these relays
could add up to a substantial amount
multiple button presses and to "lock" in a vote
would be the go here if you are going to mass produce this setup.
should be able to make the thing 2 or 3 wire quite easily then too and
massively cut installation costs.
M
mc
Guest
I suppose you could PIC each selection box and only have a daisy chain
type serial connection tthough each selector and back to the main
contoller for collection of data .yeah another possibility
make a good student project for elec/comp students ..
KLR wrote:
type serial connection tthough each selector and back to the main
contoller for collection of data .yeah another possibility
make a good student project for elec/comp students ..
KLR wrote:
On Wed, 03 Mar 2004 15:02:25 +1100, mc <phmc@cc.newcastle.edu.au
wrote:
yeah good if they all press it at the same time ..but if they are out of
sequence even ms your parralel resistor theory will not work
To prevent this happening all you then have to do is "latch in" the
first button pressed - and have a master reset line running to all
units as well to "clear" all boxes once the vote has been taken.
When latched of course by a button press - it would lock out use of
the other 3 buttons (choices) on the same panel. A small relay could
easily be used to do this in a DIY project. Of course if you had
hundreds of such boxes, the combined currents of all these relays
could add up to a substantial amount
A rotary switch (break before make) is another option to prevent
multiple button presses and to "lock" in a vote
Im quite certain that something like a very basic PIC type arrangement
would be the go here if you are going to mass produce this setup.
should be able to make the thing 2 or 3 wire quite easily then too and
massively cut installation costs.
it be more likely processor controlled polled @ certain times and
would have to be stored and checked again till all votes are in certain
time frame..otherwise you could get multiple votes from the same person ...
Mark van der Eynden wrote:
moby@kcbbs.gen.middleearth (mike diack) wrote in message news:<40450095.10486170@News.xtra.co.nz>...
I need something like these for a conference -
cheers
Mike
Probably not as difficult as you think, say each box has a 100k
resistor in it that ens up getting paralleled with with the A, B, C or
D wire. The total resistance of each wire then shows how many people
are holding down each button.
Cheers,
Mark