Re: Voting pads

On 2005-11-20, melon@xxxxxxxxxxx <melon@xxxxxxxxxxx> wrote:
> I am a secondary school teacher, and a programmer and would like to
> develop a voting pad system for my school. Could anyone give me some
> advice about what could be good possible candidates for tranmitters and
> receivers, (either RF of IR).
>
> I need to be able to receive and identify 4 different responses from
> about 30 units at the same time.

With that many units you could have frequent colisions where two units are
trying to transmit at the same time.

so some sort of polling or collision avoidance may need to be impplemented.
that'd mean having a receiver and transmitter in each voting unit.

the easiest way may be to start with a bluetooth (if it's got enough range)
or wifi (major overkill) or possibly IRDA enabled microcontroller.

the code to read (and debounce etc) the four buttons should be the easiet
part.

If you instead go with homebuilt or off-the shelf transmitters and receivers
you'll have to do the collision handling yourself.


--

Bye.
Jasen
.

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