I think any analog DAQ based solution will be
expensive. Use too many analog levels, and it will not be accurate. Use
a small number of levels, and the price per port for analog connection
will drive the price too high.
You can try using computer mice.
cheap 2 button+scroll wheel starts at 17NIS on zap.
Such a mouse can provide at least 5 events:
right button
left button
middle button (scroll wheel press)
scroll up
scroll down
You can then take apart the mouse and repackage it, maybe replacing the
wheel with 3 distinct switches.
Ofcourse you might need powered hubs if you intend to drive 30 mice.
You could try taking eight 4 port unpowered hubs (also starts at 17 NIS
on zap), and if you computer has 8 free USB ports (many do these days),
you could fit 30 mice, and hope that each port can drive 4 mice + hub.
You will also have 2 spare ports (8*4-30)for the console
keyboard/mouse.
Another direction would be to use an arduino board.
http://www.seeedstudio.com/depot/microcontrollers-arduino-compatible-c-132_133.html
The cheapest $19 board has 14 digital inputs plus 6 analog ones which
you can treat as digital if you like.
20 input pins can serve 5 users (4 input pins/user) or 6 users (3 input
pins per user if you wire them smartly - 1 qualifier signal that is
grounded by all 4 switches, and 2 more that are getting a 2-bit binary
code.
seeedstudio has free worldwide shipping for orders above $50.
Udi
2011/4/6 yosi yarchi
<yosi.yar...@gmail.com>
Hi
This is interesting idea. However, it support voting between 2 options,
only, while I need at least 4 options.
I thought that combination of analog DAQ and 4 push buttons with analog
output may help here.
Does someone have an idea about such combination (analog DAQ+edge unit)?
With best regards
Yosi Yarchi
On 04/06/2011 10:55 AM, Jason Friedman wrote:
I think the best solution would be to use a data
acquisition device, either USB or PCI.
Measurement computing sell relatively cheap devices, e.g.
this
USB one for $99:
can measure 24 digital channels (you could get two if you
need
30).
Each "competitor" could have a small switch, which connects
their input line to say a 5V power supply.
You can then write a very simple program to detect when each
competitor presses their switch
(with sub-millisecond accuracy!).
These devices apparently have linux support.
Jason
On Wed, Apr 6, 2011 at 2:44 PM, yosi
yarchi
<yosi.yar...@gmail.com>
wrote:
Hi
all
I need application that will be able to collect and process inputs from
30 (!) competitors, and will display the results very fast. The ideal
solution could be to collect the inputs via SMS: each competitor send
his answer, the application collect the answers (related to phone
number) and process them. However, I can't assume that the competitors
have mobile phones (they may be little childs...).
I thought to use 30 USB numerical keyboards as input devices, connected
with cables to 3 hubs, connected to the computer.
However, I don't have experience with USB drivers at linux...
Is it feasible? What should be the main guidelines for the solution?
With best regards
Yosi Yarchi
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--
Jason Friedman
Postdoctoral scholar
Macquarie Centre for Cognitive Science
Macquarie University, NSW 2109 Australia
email:
write.to.ja...@gmail.com
web:
http://curiousjason.com
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