[aprssig] water level gauge for APRS

[Steve Dimse]

On Oct 4, 2015, at 8:03 PM, Robert Bruninga via aprssig <aprssig at tapr.org> wrote:

> TO make a flood gage, it would seem that a simply pressure sensor like we use for atomosphere for balloon payloads would work.
> 
> Just put it inside a pipe with a cap on the top and open on the bottom.  Then the pressure will vary with the height of the water.  Connect this to the analog input of an APRS tracker and you have a flood gage.  Calibate it with some testing and done...
> 
you'd have to worry about temperature, and the chamber would have to be perfectly and permanently sealed. There is an easier way. 

It never got much traction, but there is a commercial product

http://floodadvisor.com/products.php

that is apparently still for sale, and includes integrated TNC and radio, runs for a year on a lantern battery. Their non-ham product uses satellite reporting. At this time there are just two stations still using the ham version, you can see the data at

http://www.findu.com/cgi-bin/floodadvisor.cgi

I have one at my house, but never did replace the battery when it died.

This uses an ultrasonic sensor that measures the water level inside a PVC pipe, open (copper screen) at the bottom and with a tiny vent hole at the top. I don't know what sensor it uses, but in other projects I've used this sensor with good results, 

http://www.ebay.com/itm/Ultrasonic-Module-Distance-Measuring-Transducer-Sensor-Perfect-Waterproof-/321714364470?hash=item4ae7aba036

send it a 5v trigger signal, and get back a pulse whose length is proportional to distance, easy to measure with a pic or arduino. There is a non-waterproof version for less than $2 for inside use too.

If you develop something, please consider sending with the flood advisor protocol so it is parsed by findU, then you will have graphing available for no extra effort. 

K2GE-7>APFG21,WB2SNN-15*,WIDE2-1,qAR,KC2YYW-1:=4026.04N/07421.51Ww>T+057F-030V062 FloodAdvisor -30

the data is temp, height*10, voltage*10, and at the end an optional sequence number.

Steve K4HG