??? 11/23/05 14:10 Read: times |
#104051 - not "open air" Responding to: ???'s previous message |
Erik Malund said: I dont think this is the case:
"open air" uC pins is asking for the uC to be destroyed, Valentin Angelovski said:
As for the interfacing between nodes, you could buy RS-232/485/422/whatever chips to do the job, or you can, er, 'cheat' (like i did) and just use poor ol' single-ended (single-gate versions of 74HC04 for TX/74HC14 for RX). Should be ok for the home - with CRC, of course. However, the "ring" configuration has the drawback that all nodes must be up and working, in other words, if the probability that one of the node fails is P, the probability that the whole network of N nodes fails is 1-(1-P)N. If the "home automation" is supposed only to collect data and perform noncritical operations, it is OK, but if you want e.g. to control lights or heating, this is a bad approach. Jan Waclawek |