Re: iButton home control

[james@xxxxxxx (James Derrick)]

On Tue, 10 Nov 1998 08:47:17 GMT, you wrote:

>Has anyone considered using iButtons (www.ibutton.com) as a method of
>controlling your home?  I was thinking that you could store info within
=
the
>button which could be read by your pc and the x10 kit controlled =
accordingly.
I tried the Dallas Semiconductor range of MicroLan parts some time
ago. The more commonly known DS1820 temperature sensor also has
similar parts to give 1 or 2 bits of I/O (DS2401, DS2405) as well as
the more trendy iButton digital 'keys'.=20

As these are the size of a transistor and operate on a 2-wire bus they
seemed ideal for home automation. Unfortunately, I've never managed to
get the temperature sensor working over the length of Cat3 UTP cable
from my house to the shed (150m tops). A brief look with an
oscilloscope shows the signals are being massacred by the long cable
lengths.

I use both a simple passive adaptor for a serial port (like the
DS9097) and an active design based on a buffer. I meant to try adding
termination resistors to the end of the serial bus, but like so many
of my projects, it sits on the workbench for ann other day.

The idea is sound and there are Linux drivers, just be cautious with
cable lengths.

One nice project I saw was to use the Java comms API to write a
universal front end for an iButton. This works as the Java class
provides a universal driver for the serial port that is the same
across any platform, and the iButton uses serial comms. This could
also be used to provide a universal GUI/driver for any other serial
device, like the X10 CM12U.

James
---
James Derrick    james@xxxxxxx, Cramlington, Near Newcastle, =
England
Forwarding Service: jderrick@xxxxxxx
Beyond the Horizon of the place we lived when we were =
young,
In a World of Magnets and Miracles. Pink Floyd.
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