some help in technical solution

[Omer Zak]

I think that analog DAQ with 30 channels would be an overkill for such
an application.

If you need to give each competitor 4 options, why not choose between
one of the following options:
1. 120 digital channels (5 digital DAQ modules at 24 channels each) and
provide each competitor with 4 channels, each one connected to its own
pushbutton.
2. If you prefer to build 30 4->2 encoders, each getting inputs from 4
pushbuttons and providing 2 digital outputs, then you'll need only 60
digital channels (3 digital DAQ modules, with 12 digital channels to
spare).

Of course, the final choice involves price tradeoff between:
- Analog DAQ with 30 channels + 4-pushbutton with resistors module
- Digital DAQ with 120 channels + simple 4-pushbutton module
- Digital DAQ with 60 channels + 4-pushbutton with encoder module

I assume that data processing speed is not a limiting factor.

--- Omer


On Wed, 2011-04-06 at 15:54 +0300, yosi yarchi wrote:
> 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?

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