I will get back on this one as I have other things to track. And I will check out the Angel alert.

But in the meantime, Nigel's simpler solution (the string) worked fine. He actually never left me and had plenty for string. And if it hung it on something he could break it no problem. Maybe he is getting the hint...

balfourcellular:

allelectronics.com has an RF wind shield wiper sensor (RX and TX). I bought two. I plan to send a signal from the roof (chemicals for the water tower) to a PIC on the 5th floor and beep to left the Building Manager know when the chemicals are low.

I think it was $6 US. I will post it when complete (if it works).