Re: Re: Room temperature measuring system

[Vargster <vargster@xxxxxxxxx>]

Oh, I can answer that one...

The Quasar board takes all the faff out of the 1-wire architecture...
You wire the thermo sensors into the board and a com lead to the PC, and
th=
e
temperatures just turn up as plain ascii text. Easy.

If you go the 'proper' 1-wire route, you (or rather your PC/software
solution) have to do all the grunt work, query the 1-wire network for
sensors, then polling the sensors for data, if you are running it with only
2 wires, ground + data/power, taking care not to poll to fast or you'll
disrupt the network, etc, etc,

I realise many people run 1-wire with no problems, but many more seem to
have tried and failed - me included...

I ended up with one of Justin's (off this lists) TOM10 boards, it's like
th=
e
Quasar but with 10 sensors, connected and powered by a single USB port. No
issues, no hassles, it just works (tm).

If you factor in the cost of decent 1-wire to rs232/usb converter, it's not
as cheap as it first appears.
If I was doing it again, I'd use an Arduino dev board as a base and wire
al=
l
the DS18's to it, then connect (and power) it to the PC.
Dirt cheap and =A315 a pop. Minimal programming needed. I fact I could even
give you some source code for it...

Lee



>
> I=92m just looking into the same issue as I want to keep a track of
the
> temperatures around my holiday home to try and work out the most
efficien=
t
> heating regime whilst vacated. I=92m looking at about 16 sensors which
wo=
uld
> imply 4 of these Quasar units. However I thought that the whole point
of
> 1-wire was that they worked as a bus and you should be able to link
them
> together and just have one interface that polls all devices.
>
> Dallas (or Maxim-IC as they are now) do a couple of interfaces
(DS9097U,
> DS9490R) that appear to do the same thing as the Quasar one but can
work
> with more than 4 sensors and cost about the same.
>


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