APRS Flood Gauge Ideas

Remote Sensing: APRS is an ideal remote sensing information system. Already we can track vehicles and any of 192 differnet objects and stations. We have thousands of APRS weather stations on the air, but we do not at this time have any operating flood gauges(beyond a few Steve Dimse pioneered in the Florida Keys a decade ago). With the climate changes we are seeing recently, severe flooding in Louisana and elsewhere, it is prudent for Amateur Radio Operators that participate in local emergency Preparedness to consider building a flood gauge for local areas prone to flooding.

A Variety of Simple Home Made Flooding Gauges: The images below suggest several ways to built a flood gauge. The one on the left can be built from any TNC, any Radio and any kind of hardware float switch. When placed at the proper location and adjusted to the right flood activation level, this type of gauge can give an alert that the water has risen to a concerned level. But from then on, pubic service personnell or a ham will need to be dispatched to report on higher levels.

Batteries: Originally, I had considered solar powered gauges, but this drastically complicates the gauge for several reasons. First, the solar panels dont fit in a pipe, and most gauges are down in valleys and shaded. For this reason, all these gauges run on Dry Cells and are only activated when the water gets above a certain pre-determined activation level. This way, the batteries should last for well over a year. The design should include a simple means to activate it for test, either a magnetic switch or a means to flood the gauge with a gallon of water or something like that.

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Two-Level Design: This design shown in the middle above still uses two simple float switches, but the first one only activates the power and begins sending an activation level symbol and alert beacon. Later, if the flood level float switch is triggered, it then flips the Bank-Select-configuration bit in the tracker device that changes then the symbol and the beaccon text to alert that the flood level has been reached.

Design Notes: There needs to be a tiny hole in the pipe at the highest waterr level ever expected so that the water can rise inside the pipe. Also, putting the batteries low is not practical because of water imersion.

Best Flood Gauge: The best design on the above right, still uses float switch to activate the system when water rises above an activation level, but once that has been activated, then a untrasonic water level sensor (shown here at right) is activated along with some kind of CPU such as a Basic stamp or Arduino to then send out actual water level readings while also changing the warning beacon text and the symbol colors. For the real world, be sure to get the weather proof sensor at the far right and it fits better in a pipe! This sensor is actually a distance sensor but when placed in a PVC pipe can be used to read the height of the water too.

The Float Switch spec sheet
Another possible level detector
Spec sheet for Ultrasonic Sensor
Web page for Waterproof Level Sensor (use this one!)

Expanded APRS Symbol Set: The larger APRS symbol set initiated around 2007 now has hundreds of symbol possiblities such as the tables below. See: symbols-new.txt. The new symbols are defined as overlay characters onto the original basic symbol set. This allows all older systems to still see the basic symbols but to also then display the new overlay characters. Then clients with the patience can implement all the new possible symbols that can be triggered by these symbol/overlay combinations.

This set shows the original name and primary and alternate symbol as well as the proposed name change and new alternate base symbol (if needed). IN this example, the human symbol was expanded with up the 36 possible "Human" overlay characters, each representing some unique human activity related to APRS. In this way, you can see that each of the 96 fundamental APRS symbols now has 36 possible expansion symbols. triggered by the alphanumeric overlay character. For example, now we can send the code for a GREEN, RED or YELLOW Flood gauge, or can create a symbol for a water stop if someone came up with a nice graphic.

Current SYMBOLS SPEC (version 1.1 plus non conflicting parts of 1.2). .
New version 1.2 symbols with new expandable Overlay blocks
UI-View latest symbol file
APRS version 1.2 Overlay Expansion Proposal. A description of the overlay expansion on all alternate symbols..

As long as new software developers recognize both the old and the new alternate weather symbols the new APRS1.2 Symbol set will work with little confusion.