Tank water level sensor.

[HellasTechn]

Hello friends !

Here i am today, thinking about my new project which is a water level sensor for a tank.

I think it would not be that hard to write a code on a picaxe for such project but what sensor should i use ?
On the web i have seen ultrasonic sensors for arduino used as water level sensors but i am not sure how theese sensors work.
A simple logic 0 and 1 from a sensor indicating water or no water would be enough but an analog sensor would not be bad also (to be able to chech the actual remaining percentage).

Any ideas ?

Thank You !

 

[kellys_eye]

A float switch is the most common method of detecting water/no water.

If it's quantity then you could measure the pressure at the bottom of the tank.

Ultrasonic measurement works but that means having the sensor in a moist atmosphere and the associated problems with corrosion etc.

 

[HellasTechn]

float switch can do the job,
a pressure sensor is not a bad idea. Do they give analog signal based on measured pressure at the bottom of the tank ? could you suggest me one ? the tank holds about 250 US gallons (1000 liters of water.)
About the ultrasonic , i am not sure.

 

[Minder]

What is the depth of the tank, a float switch is a simple device and can also be easily constructed, from copper/brass pipe or Sch 40 PVC, just requires a reed switch at the required position in the sealed tube and a circular float material around the pipe that carries a small magnet.
M.

 

[Alec_t]

.... and the reed switch method that Minder suggested can easily be extended to have several reed switches at different depths.

 

[kellys_eye]

You can, of course, purchase tank level sensors dedicated to the task, many of which are used in the marine (yachting) industry to meter domestic water tank levels.
Those operate using a float and arm assembly that rotates a variable resistor and provides a variable DC voltage for direct meter reading (suitably calibrated of course).

 

[HellasTechn]

What is the depth of the tank, a float switch is a simple device and can also be easily constructed

the depth is about 1 meter. The reed sw will have the same moisture problem as the ultrasonic sensor.
The problem is that there is very little space inside the tank so installing a float switch does not strike me as the easyest thing to do. I think a simple pressure sensor is the easyest way to go. Just wire it up and drop it at the bottom of the tank.

At the moment i guess i will stick with the cheapest solution... how much does a pressure swnsor cost ?

 

[HellasTechn]

You can, of course, purchase tank level sensors dedicated to the task,

I know but it is their price that is keeping me off !

 

[Bluejets]

Use one of these. ($5.00)

http://www.ebay.com.au/itm/NEW-DIP-...863889?hash=item3d3480d6d1:g:~mQAAOSw7GRZHu9O

Connect tube to bottom of the tank and mount sensor above high water mark.

Edit...more detail on how to use it here...

http://langster1980.blogspot.com.au/2014/11/how-to-use-pressure-sensor-with.html

 

[Minder]

the depth is about 1 meter. The reed sw will have the same moisture problem as the ultrasonic sensor.

Why would moisture be a problem in a hermetically sealed tube?
M.

 

[KMoffett]

Here is a full/empty water level control circuit that I did with a PICAXE to automatically keep my Christmas tree stand filled. Three 316 stainless steel electrodes with AC coupling to minimize corrosion. Used for a month at a time for many years with no sign of corrosion.

http://www.picaxeforum.co.uk/showthread.php?12266-08M-Christmas-tree-watering-controller

Ken