some help in technical solution

[Udi Finkelstein]

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.yarchi at 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:
> http://www.mccdaq.com/usb-data-acquisition/USB-1024-Series.aspx
>
>  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.yarchi at 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
>>
>>
>>
>> _______________________________________________
>> Linux-il mailing list
>> Linux-il at cs.huji.ac.il
>> http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
>>
>
>
>
> --
> Jason Friedman
> Postdoctoral scholar
> Macquarie Centre for Cognitive Science
> Macquarie University, NSW 2109 Australia
> email: write.to.jason at gmail.com
> web: http://curiousjason.com
>
>
>
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>
>
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