[Cialug] Wireless instrumentation

[Zachary Kotlarek]

On Dec 5, 2007, at 11:31 AM, Morris Dovey wrote:

> I'm looking for input. I'd like to monitor temperature (0-200F),
> airflow (any linear unit/any time unit), and sunlight brightness (full
> dark - full sun) at periodic intervals and accumulate the data (either
> on the fly or daily/weekly/monthly poll) for analysis.

I don't know about airflow or brightness monitoring, but I've used 1- 
Wire temperature sensors in my thermostat project and I've been very  
happy with them. Something like the DS1820/DS1822/DS1825 is about $2  
per sensor (less for the DS1822), reads in under 1 second, has a range  
of like -100F to +250F, and has an accuracy of better than 1F.

The 1-Wire interface is nice even if you use all three wires -- you  
can string a bunch of these together on a single serial port, with  
little interface hardware, and be limited only by the bus speed. If  
you only need to get an update from each of them a couple of times an  
hour you could string together hundreds on the same bus without a  
problem. There are cheaper options in other interface systems, like  
the DS75 which uses SMBus, but if you need more than a handful of  
sensors you'll end up with a lot of interface equipment to get them  
all connected.

I'd show you my temperature-tracking web interface, but I didn't  
create a read-only mode, and I don't want you guys mucking with my  
thermostat settings. ;-)

	Zach
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