IR network for PIC-processors

Sound like the ideal config for a hub. The central controller should have 10 sets of TX/RX and be powerful enough to route the traffic.

The required data rate is very low, so I would prefer simpler hardware (one LED and one LED-receiver) i each caroussel. I would prefer decetralized topology becouse the dias caroussels can be put up without knowing anything about network configuration.

- kristoffer ek

Peer to peer would complicate software significantly. Hub and spoke would be simpler.

Same thing. The host can just deactivate the non-responsive node.

I know, but the software I build now actually do the works, but I was looking for something more standard-like.

Actually some of the nodes acts as hubs when they can "see" more than one node.

My protocol works like this:

when receive packet: to me: send ack

not to me: resend packet

plus collision detection on every sent packet.

- stoffer

Perhaps applicable to your application, HP had developed a low cost IR (2400 baud) interface for use in some of their computers, printers and calculators. It was known as 'HP-SIR".

Other manufacturers had used it, but IRDA had then taken over.

The article "An Infrared Link for Low-Cost Calculators and Printers", in the the October 1987 issue of the HP Journal has details.

TomC

node.

How far apart are the nodes? IR only have narrow angle of view as well.

node.

most of them can se each other. My question is about how to design the protocol :-)

- kristoffer ek

one node.

You might want to take a look at the zigbee stack. Just change RF to IR.

Thanx, thats a good suggestion, according to what I read about zigbee it looks pretty much as my stack is a beacon-less version of zigbee - wonder if there are any zigbee software stacks?

- kristoffer ek

Microchip has zigbee stack for PIC18 and PIC24, but you would probably need 64K to 128K flash.

to

The ZigBee sample router is around 64K for PIC18 and 96K for PIC24. So, you probably need 128K PIC18 or 256K PIC24 to do anything useful.

You probably do not need to implement a full ZigBee, in which case you need less than 128 kB.

The RF4CE stack on top of an 802.15.4 radio will do just fine. Atmel has a qualified stack for this that runs on top of the ATmega128RFA1.

Yes, but it's not going to work on 32K PIC18f2550. If the OP wants full Peer-to-Peer, he will need bigger chips. However, he can have 3 to 4 routers and the rest in devices only. Devices might fit in 32K, but not routers.

They can "se" each other at up to 10 meters...

Yes, I think its overdoing it with zigbee

A lot of the code is dealing with routings, with ZigBee or IR. If you want Peer to Peer, you have to deal with routings. If you want simpler protocols, use star (master to slave) configuration.