Folkestonomy


Starting a prototype

I can read one ID, therefore I can read many.
I can read one ID, therefore I can read many.

Some of the 1-wire samples I've ordered from Maxim have turned up. I ordered a 1-wire Evaluation Kit, but it appears to be on back order, which could hold things up. The fact that it has to ship from the US, via the ever painfully slow UK customs, is making me nervous. In the meantime I ordered some parts from homechip to allow me to get on with testing the network ideas.

First step is wiring up a 1-wire reader and a 1-wire Silicon Serial Number ID chip, and seeing if I can get them to show up on my MacBook. The hardware itself is simple enough, but the software is more challenging.

Some googling throws up a Mac OS X compatible version of the one wire viewer. After some playing round, and reading all the comments, I manage to get it working, and I can swap serial numbers in and out on the board all nicely.

The software isn't really going to be much use in the final thing alas; There are a few options here though, I can use the basic libraries in here and extend oit to get the data out and into whatever database I want, or I can use other available software, such as the One Wire File System to read what's on the network. The problem seems to be that the mapping we need would require the network to be cut into segments, whereas the default one-wire network is just one long string of IDs.

I've been thinking about using an Arduino or Wiring microcontroller to talk to the one wire network; there are some libraries which appear to allow talking to one-wire nodes directly. The catch here maybe one of timing and accuracy: each network we have may be quite long, and so the timing issues on the 1-wire network may become a problem.

Again there are some options here using 1-wire hubs. It doesn't fit with my feeling of keeping it simple however.

More work to be done...


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