On 05/03/2013 19:27, Andrew Gabriel wrote:
In article ,
"David.WE.Roberts" writes:
At the moment I have three 'weather stations' which are an indoor
thermometer and clock and atmospheric pressure sensor, and a remote
temperature sensor.
The first I bought from Tcibo, and it has been very reliable.
The other two are from Lidl/Aldi and both keep losing contact with the
external sensor.
So not that much good.
Not the temperature sensors fighting each other as one was for the camper
van and it didn't work well out in a field with nobody else around.
Now I would really like to be able to have a number of temperature sensors
around the house, both inside and out, and to read all the temperatures at
one station, preferably a PC.
Now these 'weather stations' are pretty cheap, so the remote sensor must
be very cheap.
So you would think that you could buy say six budget temperature sensors
and a base station for this kind of application.
However Google is so far not my friend.
Anyone done this kind of thing?
I use dallas 1-wire digital thermometers around the house.
These are not wireless, and require a twisted pair to link
them all, or 3 conductors, depending if they are driven in
1-wire mode, or with a separate supply line.
You will need something to interface the Dallas 1-wire
protocol to a serial port or a USB-serial adaptor.
A raspberry pi can just about bit-bang the dallas 1-wire
protocol with the 1-wire driver included in the Wheezy
distro (which will only do a single 1-wire bus AFAIK, but
you can have lots of sensors on it), and that's not very
expensive. (It occasionally fails to read the 1-wire bus,
but you can simply do it again when this happens.)
Before doing this I bought a bare 433MHz receiver with a
view of decoding the Oregon Scientific signal, but I gave
up trying to make that work. (I could see the transmissions
on a scope, but they were very hard to separate from noise
in software, and I didn't get as far as working out what
the encoding was.)
In a similar vein, my house contains a small network of "2-wire" digital
temperature sensors based on this design:
http://www.riccibitti.com/pc_therm.htm