[aprssig] water level gauge for APRS

Robert Bruninga bruninga at usna.edu
Tue Aug 16 17:19:30 EDT 2016

Revisiting the Flood gauge for APRS idea... due to some interest at FEMA
I found some sealed float switches $10 that will fit along with 4 D cells
and a 2 Watt Tinytracker from Byonics in a 1.5" PVC pipe.

We use two switches, the first one just above normal water to turn the
thing on, and then the second switch at a level that changes the beacon
from GAUGE ACTIVTED to FLOOD ALLERT or something like that.  It is
tempting to include actual height, once it is on, but this two swtich idea
is a starting point.

Will also include a magnetic microswitch so that it can be tested by
holding a magnet to the right spot on the outside.  Batteries should last
a year or more, since they are never on except during flood events.

If we can get FEMA to buy a bunch of switches and other parts, how many
people might invest $X to complete them?  The Microtrack is going to be
probably in the $150 to $250 range, and I doubt I can get FMEA to buy them
in bulk.  Though, that is going to be my going in position...

(Or any other TRACKER product on the market that will fit in a PVC pipe
and have at least two configuration beacons that are switch selectable.

Bob, WB4aPR

-----Original Message-----
From: Steve Dimse [mailto:steve at dimse.com]
Sent: Sunday, October 04, 2015 11:54 PM
To: Robert Bruninga; TAPR APRS Mailing List
Subject: Re: [aprssig] water level gauge for APRS

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

> 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


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


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,


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.

030V062 FloodAdvisor -30

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

Steve K4HG

More information about the aprssig mailing list