On 20/07/14 01:28, Jaime E Oliver wrote:
On Jul 19, 2014, at 3:34 AM, Simon Wise via Pd-listpd-list@lists.iem.at wrote:
Maybe you have the laptop running audio and want several projections, or want to use the GPIO features which are not available on a laptop. Pis are a compact, cheap, low-power way to do this (if they are up to the task you have in mind …
Just continuing with that thread, what are the best ways to send and receive messages with a Pi via UDP or similar?
Is it possible to connect them with an ethernet cable directly without a router?
certainly a Pi and a laptop can be connected directly by an Ethernet cable, that is an easy way to work on a Pi via ssh and just needs the two to have compatible manual addresses set. It is described in all the basic Pi how-tos.
That also works fine for a laptop and a single Pi, say with Pd running on each passing messages via UDP in the usual fashion.
For more than two devices and UDP over Ethernet you will need something connecting them all ... say a router, or a switch if they all have manual addresses, or if you just need cueing and latency isn't critical you could use wifi with the laptop running as the access point (but probably best to choose TCP in that case).
There are other ways to communicate if you want ... but they take a bit more effort ... they could be useful in some cases. You may want a bunch of Pis controlling a bunch of projectors and audio where they can be mounted close together ... if you wanted very tight sync you could connect them so they shared a clock and communicated with each other via one of their GPIO protocols, with pd on each and one of them connected via Ethernet to a laptop if required, or one of them running an interface with a screen or desktop and acting as the controller while the others dealt with the media, or something like that. The possibilities are endless.
Simon
best,
J