Hello, I'm new on Arduino Projects and i don't know how to measure a river elevation.
If i know the depth of the river, i need only know the distance between the river and the sensor.
I don't know what kind of sensor should i use, it need not be very accurate because the distance between the river and the sensor is great.
Thanks.
Maybe an ultrasonic distance-sensor?
DVDdoug:
Maybe an ultrasonic distance-sensor?
I thought about it, but i only found the HC-SR04 sensor but it's maximum range is 450cm and i need more.
Maybe a mix of a GPS module and a barometer?
Let's make sure we don't have a language barrier thing happening here. When you say elevation, do you really mean elevation or depth? The elevation is easy, a GPS floating on the rivers surface will give you the elevation above sea level.
If you want depth of the river that is a much more involved process. Underwater sonar is not something you can typically hack together at home.
Johnny010:
Maybe a mix of a GPS module and a barometer?
I have no idea how to use a mix of GPS and a barameter... can you explain ?
I'm thinking about this:
tihbaptista:
I have no idea how to use a mix of GPS and a barameter... can you explain ?I'm thinking about this:
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Ok, maybe you are wanting the depth...
Can you maybe draw a diagram and use the img tags to show it here.
Draw us a picture to show what you are trying to measure.
Are you trying to measure the depth of water running over a bridge under flood conditions ?
We have problems with the overflow of rivers due to heavy rainfall in this region, I would like to measure the elevation of the river at various points to advance warning of flooding.
Another option is to measure water depth.
Maybe with a "bubbler"
Enter that in the search box on top of this page.
Leo..
the level of the water is the same from one side of the bridge to the other.
mound the sensor down low enough so that it can work.
hack this ?
http://www.ebay.com/itm/191351740039
how many meters in 60 feet ?
will it work on waves and a non-flat surface ?
another, but much more expensive way is to measure water depth with a submersible pressure sensor. these are very expensive, but very accurate. you can mount in a concrete vault because water pressure will effect anything under water.
What is the distance range you want? Maxbotix has 10 m max sensors. Will that be enough?
dave-in-nj:
another, but much more expensive way is to measure water depth with a submersible pressure sensor. these are very expensive, but very accurate. you can mount in a concrete vault because water pressure will effect anything under water.
A bubbler is a cheaper variation of that.
A (gauge) pressure sensor, a small air pump, and a thin plastic hose to a concrete block in the river.
Pump air in the hose untill the pressure doesn't increase anymore (bubbles escape).
The air pressure is the water depth.
Repeat every 10 minutes.
Leo..
Wawa:
A bubbler is a cheaper variation of that.
A (gauge) pressure sensor, a small air pump, and a thin plastic hose to a concrete block in the river.
Pump air in the hose untill the pressure doesn't increase anymore (bubbles escape).
The air pressure is the water depth.
Repeat every 10 minutes.
Leo..
need to supply compressed air, not feed from a compressor. the pulses are way larger than depth.sensitivity.
accuracy depends on sensor, but un-manned operation requires the compressed air is refilled. you can pressurize with a compressor, but that requires power.
Little tube with the ends sealed goes down from the bridge. Inside are hall effect sensors and wires running back up. Outside the tube is a float with a magnet inside of it around the tube. As the bob goes up and down, you sense it passing the hall effect sensors. Low granularity, but for flood watching that's all you really need. Maybe one sensor per foot and you always know the depth to within 12". If it might get damaged, then the whole contraption might be put inside of an outer tube with the ends open so the water level inside will rise and fall with the river.
Suppose you immerse two parallel conductive rods into the water. The water between the rods represents a resistor, and the further up the rods the water comes, the lower the resistance, in a linear relationship. So you put another resistor in series with this resistor, to get a voltage divider, and now scale it so you can use analogRead() to determine a voltage.
The only gotcha I can think of is water temperature and water chemistry may affect the resistance. So you arrange for a small pair of control rods, conductive along only a fixed length, to remain fully immersed in the water to determine how to interpret the resistance on the rods you are using for measurement.
dave-in-nj:
need to supply compressed air, not feed from a compressor. the pulses are way larger than depth.sensitivity.accuracy depends on sensor, but un-manned operation requires the compressed air is refilled. you can pressurize with a compressor, but that requires power.
Run the compressor for several seconds (long enough to expel the water from the tube), stop the compressor then measure the static air pressure. This also eliminates errors due to frictional drag of air moving through the tube giving a false high pressure reading.
