Using the IR Buddy with Multiple Robots
Archiver
Posts: 46,084
We want to know if it is possible to have multiple streams of incoming data over
IR.
Here's the scenario: We have several robots wandering around and sending a call
to
one central basic stamp (connected to a computer). They are also sending calls
to
each other. Is there going to be a problem with signal collision? Can the
signal
collisions be minimized or avoided with start/stop bits? Is it that simple or
is there
anything we're missing? We're using the IR Buddy on each robot, and as you know
they all have the same frequency.
Any help you can offer is appreciated!
Robo4 Team
Sabrina L. Nelson, Marie Masoumi, Tony Chang, Lizhen Yang
Cal State Hayward Multimedia Masters Program
IR.
Here's the scenario: We have several robots wandering around and sending a call
to
one central basic stamp (connected to a computer). They are also sending calls
to
each other. Is there going to be a problem with signal collision? Can the
signal
collisions be minimized or avoided with start/stop bits? Is it that simple or
is there
anything we're missing? We're using the IR Buddy on each robot, and as you know
they all have the same frequency.
Any help you can offer is appreciated!
Robo4 Team
Sabrina L. Nelson, Marie Masoumi, Tony Chang, Lizhen Yang
Cal State Hayward Multimedia Masters Program
Comments
Multiple IR transmissions at 40 KHz (which
is what the IR-Buddy puts out) will step on
each other at the receiving Diode.
You can detect them with something as simple
as a checksum on a small data packet.
You can work with this with a variable timed
hold-off before talking after a collision
(how ethernet does it), or having the master
poll each 'slave' (token passing), or having
'time-slots' assigned to each slave 'bot'
when it knows it is allowed to talk.
(this last approach can be tricky, since
you want to insure their clocks are synchronized,
which is hard on a BS2)
I'd think the easiest approach would be to
have the 'master' send out a very short message
to each 'slave', one at a time, to tell it to
'talk now', while the others 'listen'. Each
slave would have to know what its ID is,
so the master could uniquely address each one.
--- In basicstamps@yahoogroups.com, "sabrina007mac"
<sabrina007mac@y...> wrote:
> We want to know if it is possible to have multiple streams of
incoming data over IR.
> Here's the scenario: We have several robots wandering around and
sending a call to
> one central basic stamp (connected to a computer). They are also
sending calls to
> each other. Is there going to be a problem with signal collision?
Can the signal
> collisions be minimized or avoided with start/stop bits? Is it
that simple or is there
> anything we're missing? We're using the IR Buddy on each robot,
and as you know
> they all have the same frequency.
>
> Any help you can offer is appreciated!
>
> Robo4 Team
> Sabrina L. Nelson, Marie Masoumi, Tony Chang, Lizhen Yang
> Cal State Hayward Multimedia Masters Program