Some time ago (8/2008) I posted a long message about my attempts to use an ultrasonic sensor and a Basic Stamp programmable logic controller to build a snow depth sensor.
Much of it works fine. It is solar powered, using 2 12 volt panels to charge 2 alarm system batteries providing both 12 volt and 24 volt DC power. The sensor is a SensComp mini ae, and the output is an analog voltage (0-10VDC) which the analog-to-digital converter in the Stamp PLC converts. The data is then sent by radio modem to a nearby (indoor) PC where I can access it via FTP over the internet.
All the above works fine EXCEPT:
The SensComp sensor ( Mini-AE # 616100) works perfectly when presented with pieces of plywood at differing heights. All are reported correctly. When the snow started, it immediately reported 9.99 volts. In other words, it reports maximum range voltage, which I interpret to mean the echo from the snow surface is not being “heard” so the assumtion is it is beyond maximum range. There is a sensitivity adjustment on the sensor itself which is currently set to maximum. The sensor is about 8 feet from ground level, and the snow depth is currently about 2 feet.
I have visited one website for a somewhat similar system employing a senscomp Mini-AE and remarks there suggest that the sensitivity may be set too high.
see: http://voksenlia.net/met/snow.php
Does anyone have any experience with this sensor? Its very difficult to get to the sensitivity set screw on the sensor as mounted, and I was hoping to avoid doing this too many times if possible.
Thanks, Warpdrive