Liquid level sensor SN-LLS

[qinhong]

hi, i'm using this sensor in my project. i have a few questions to ask.
1. is it sure that the middle port of the sensor is not needed?
2. can the entire sensor immersed in the water tank? is it water proof?
3. how many millilitre of water can it measure? ( the sensor length is around 25cm. what if my tank is more than 30cm? )
4. how the sensor can be controlled by the microcontroller? is it required any kit? can it operation with only assembly language or C language better?

[sich]

First of all, you need to study the datasheet.

1. is it sure that the middle port of the sensor is not needed?

2. can the entire sensor immersed in the water tank? is it water proof?

Yes...

3. how many millilitre of water can it measure? ( the sensor length is around 25cm. what if my tank is more than 30cm? )

It measures the level, not volume. You will need to calculate the volume on your own because u're the one who decides the container.

4. how the sensor can be controlled by the microcontroller? is it required any kit? can it operation with only assembly language or C language better?

It has nothing to do with using which microcontroller or programming in which language. It's just like a variable resistor. You can measure the resistance using multimeter too. If you're to interface with microcontroller, get one with analog to digital converter (ADC) module. You may refer to this tutorial. This is flexi-force sensor, but the connection is similar to liquid level sensor. The writer introduces two microcontroller platforms - BBFuino (Arduino compatible) and SK40C (using PIC16F876A).