[aprssig] water level gauge for APRS

[steve at dimse.com]

In the non-waterproof version the electronics and the sensor are on a single board, in the waterproof one the sensor is separate from the electronics. Both versions work the same way - an U/S pulse is fired after trigger pin sees a rising edge. When the signal is sent the output pin goes high, and when the return is detected the output is pulled low. The width of the output pulse is the round trip time for the sound, multiply by speed of sound and divide by two to get the one way distance between the transducer and the water.

The chip in these is not programmable, it is a dedicated distance sensor, so you need a microcontroller of some sort to initiate the reading, time the pulse, and do the math. The same micro could format and send the packet in the usual manner.

Steve K4HG

> On Aug 21, 2016, at 4:17 PM, Robert Bruninga <bruninga at usna.edu> wrote:
> 
> Thanks steve,
> 
> I was confused by the waterproof sensor as to what was in the sensor and what was that other circuit board shown in the Ebay listing?  Is that just a micro do do something with the time pulse you get back, or does the $7 just get the sensor and it works like you describe as is.  We would tnen add a packet generator cpu, but we can all do that.
> 
> So can you clarify what are the wires coming out of the sealed unit?  and what is the circut card shown?
> 
> Thanks
> Bob
> 
> 
> On Sat, Aug 20, 2016 at 8:53 PM, Steve Dimse <steve at dimse.com> wrote:
> 
>> On Aug 20, 2016, at 8:03 PM, Jason KG4WSV <kg4wsv at gmail.com> wrote:
>> 
>> A better question is what do the component datasheets say about long term operation in a 100% humidity environment?
> 
> That's why I'd spend the extra money for the waterproof one, even for a throwaway it isn't that much more. Then it is easy to separate the electronics from the water.
> 
> I used a a pair of reducers to take the ID of the 2" pipe down to the diameter of the sensor (3/4" if I remember right was just a little tight and was sanded out), then a 2" F-F coupler and a watertight junction box for the battery and electronics. Potted out the top where the sensor attaches with some silicon caulk. All of this was shamelessly stolen from the Flood Advisor mechanicals.
> 
> Steve K4HG
> 
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