Good pressure sensor for lake water level?

Tinker

Hi - I want to make a logger that records lake water free surface height. What I've done in the past is to use a 4" PVC pipe with end caps as the housing, mount a 4-volt output, gauge pressure, pressure gauge with a dynamic range of about 200" of water. The Mouser catalog has a PC board version for about $70 with reasonable linearity (Allsensor makes it). I would bring in the water pressure via tygon tubing filled with silicon oil. Electrical connections would be made through a water-tight feed-through connector. Has anyone else made one of these? When they are placed in the ocean they become tide gauges............................................Pete Smith

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cyberbiota

Pete-

Honeywell makes a large variety of pressure sensors in different configurations (pressure, gauge, differential) with both amplified and unamplified outputs. If memory serves, they run 15 to 30 dollars each in small quantities. Check out:

http://content.honeywell.com/sensing/prodinfo/Pressure/

Motorola (now called Freescale) also produce a line of pressure sensors in a bewildering variety of configurations/outputs/formfactors. Check them out at:

http://www.freescale.com/webapp/sps/site/taxonomy.jsp?nodeId=01126990368710

I have used pressure sensors from both manufacturers in microcontroller designs, and found them to work equally well.

Good luck!

peter

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Peter C. Charles

Director, Research and Technology
CyberBiota, Incorporated
Peter.charles@cyberbiota.com
http://www.cyberbiota.com

Yanroy

I'm sure you have a good reason for using a pressure sensor instead of an actual level sensor, but I'll make my suggestion anyways.· An ultrasonic rangefinder mounted above the water pointing down will give you a distance to the surface.· If you know how high off the ground the sensor is, you know how deep the water is.· This strikes me as the easiest and cheapest solution.· I've used exactly this method in measuring snow depth.