collision Avoidance

[c.bennardo]

Hi,

I'm doing a Medical application with PAN4561.
In my application an electronic pedal controls and turn on/off a laser.
I want replace the cable with a PAN4561.
I need that in case of packets collision the PAN4561 change automatically the channel, in order to trasmit the packet as soon as possible.
I can manage a delay up to 400ms
Is possible to do this???

Thanks

[kbanks]

The strict requirements of your application put it outside the scope of our user forum. Please contact our Custom Solutions group.

I can give you a few hints to get you started in your investigation:

1) Look at the getEnergy() built-in. It could possibly be used to detect the interference (which could trigger the channel change).

2) There are NV parameters for carrier sense and collision detection, but they can not do what you want. They only affect the low-level transmission of packets, they do not report anything back to your script (nor do they support changing the channel).

3) To me the big trick seems to be somehow synchronizing the channel changes. If your "transmitting node" decides to change channels, your receiving node better be on that new channel too. Offhand I do not know an easy way to do this.

I think your application would require a customized version of SNAP. Again, contact our Custom Solutions group.

[Kham]

c.bennardo , do you mean collisions other than the ones handled by the 802.15.4 stack?
400ms is plenty of time for packet retransmission for something like a on/off indicator.

As with anything for 'medical' there is a lot to red tape to get through I would imagine.

How far do you need to go?
The PAN4561 may be overpowered for you application if you only need to transmit across a room.