RF Transmitter Receiver Recommendation?

[dhouston]

That sounds like all six in one second.....

One of the XBee modules like this: http://www.sparkfun.com/products/8664
fits the distance, legalities, and timing specs. It's only $19.00 at DigiKey.com, and is highly configurable.

If it is a 1 second burst containing all 6 sensors, I agree - this is ideal.

[markedwards]

I appreciate all your insight. I work on equipment installations and it always seems like the sensors are spread out in multiple locations. Example a cooling tower has 2 or 3 temperatures, water level pressure and flow. Down a flight of stairs to the pump room, then up the ladder to the roof...
I was hoping to install a few diagnostic transmitters to temporarily monitor operating conditions.
The Xbee looks reasonably priced.

Thanks,

Ed

[dhouston]

The Xbee looks reasonably priced.

But it seems that you need multiple transmitters to avoid running wires up and down the stairs.

Can you be a bit more explicit about sensor locations and whether you want continuous or periodic operation?

[markedwards]

But it seems that you need multiple transmitters to avoid running wires up and down the stairs. ?

Yes absolutely!

Can you be a bit more explicit about sensor locations and whether you want continuous or periodic operation?

I was thinking real time data w/ 1 reading per second per each sensor (6 readings per second) would be good

Some systems operating conditions can ramp up and shut down in a matter of seconds others rarely change. I have experienced an intermittent high pressure switch
that caused rubber hoses to ocassionally fail.

I have never had an opportunity to work with radio communication and thought this would be a good project to learn.

[mackrackit]

I have never had an opportunity to work with radio communication and thought this would be a good project to learn.

It does sound like a good placed to learn. You will also get to see how motors and other equipment, along with reinforced walls and such interferes with the signal.

[dhouston]

I was thinking real time data w/ 1 reading per second per each sensor (6 readings per second) would be good.

The FCC limits this type of transmission...

In addition, devices operated under the provisions of this paragraph shall be provided with a means for automatically limiting operation so that the duration of each transmission shall not be greater than one second and the silent period between transmissions shall be at least 30 times the duration of the transmission but in no case less than 10 seconds.

[markedwards]

The FCC limits this type of transmission...

Thanks Dave.

I read the considerations for operating in the 260 to 470Mhz frequency band and it would not allow my desired update rate.
I started researching the zigbee/ xbee modules.

Mark

[dhouston]

Mark,

Sorry I was a bit late as I was back in the hospital for most of this week.

I'm not as familiar with XBee as I am with the lower frequencies subject to FCC Part 15 Regulations but I believe it will be a better fit for what you want to do.

1. It's pre-approved by the FCC. Getting Part 15 approval can cost several thousands of dollars. There's a loophole for "homebuilt" designs but your application sounds too commercial to fit the loophole.

2. There's much more spectrum and frequency hopping is automagically included so I suspect you can meet your desired schedule. If not, since they are all transceivers, you can do a query/response schedule from a master unit which will be simpler to manage than random transmissions from multiple transmitters.

Good luck and keep us updated - this is likely to interest many others.