I have been looking for information on wireless data collection for some places that have little or no access. I could hard mount the sensors but was thinking about wireless. I can't seem to find information on this type of monitoring. Would like to hear some pros and cons on doing this.
thanks

Look around the net for wireless sensors. There are sensors that wake up and collect data on a time schedule, others make up what is called a mesh net, some use RF standard others use something other.
Most, however will have issues with battery life, there are work arounds, others mostly due to battery life will limit the resolution of data collected.

Try looking at Azima Power, Techkor, and others.

We use the wireless sensors from CSI a Devision of Emerson Process management in Knoxville, TN

**vendor**

http://www.dliengineering.com/detail.asp?nID=55

This is a link to a wireless system - this one uses "normal" sensors wired to a small data acquisition device that connects via WiFi to your network.

benefits are no batteries, you can querey the sensors at any time, you don't pay to have a transmitter in each sensor, just one for a group...low cost...email me if you have questions..

Anyone have any feedback on some of the limits of wireless systems? Be it wireless sensors or wired sensors going to a wireless transmitter?
Ideal frequencies 900 mhz, 2.4 mhz ...?

If you use 802.11 WiFi, there are alot of commercial options for antennas and transmitters that can send data further than you'll probably ever need. For example, I take a ferry to work and it has WiFi that's being transmitted a couple of miles across the Puget Sound (in Seattle)from a moving ship.

http://www.dliengineering.com