hi,i got some problem..
i got a vertical liquid sensor which is float switch that is use for flood or water spillage..and my sensor is control by the microcontroller,
then am i need a circuit to operate the float switch?
or it is a stand alone device?

 

Most likely, it is a mechanical switch that opens (or closes) when the float rises. If it only has two wires, then that is all it is.

If it closes when the float rises, you could wire it in series with a bell or a piezoelectric buzzer.

If it opens when the float rises, then you could use a relay to turn on the bell or buzzer.

If you want to use it as an input to something more sophisticated, let us know...

 

I agree.

You may want to go to a hardware store and just take a look at a sump pump. You can see how the float is connected directly to a microswitch to give the 'too high' and 'low' signals to the motor to pump the water.

You can easily use logic levels to send the info to a microcontroller or whatever you would like.

Here is a replacement pump-float switch that you can add into your design or just see how it works:
http://www.homedepot.ca/webapp/wcs/...ode+matchall&recN=112148&N=0&Ntk=P_PartNumber

 

The float switch if it is similar to a pressure switch it is a stand alone device. No need for external circuit to act / deact. The question is: what do you want to drive with this particular switch?

 

many floats are simply a magnet and a reed switch. NC/NO dry contacts

 

Floats can also contain a small mercury switch and be suspended to tilt or hang. These are more suitable for sumps and a dirty environment.

Just treat it as a make or break switch to drive anything you want.

 

thanks you all for replying..
i found that the switch act like a resistor..it will close when the float rises...
so when i give a input to the circuit, and when the float is rises, it will perform a closed loop and conduct electricity..so the 10K resistor is it enough to limit the current flow through?

 

thanks you all for replying..
i found that the switch act like a resistor..it will close when the float rises...
so when i give a input to the circuit, and when the float is rises, it will perform a closed loop and conduct electricity..so the 10K resistor is it enough to limit the current flow through?

No one could know if s 10k resistor will be enough. You have not said what voltage and current the switch will be exposed to.

Also, you shouldn't need a resistor for a switch.

 

Actually, you can need a pull up or pull down resistor if it is being turned into a digital signal. I've designed my share of such systems, if there is processing involved (nothing sophisticated, just logic) then you are probably going to use the switch as a logic signal instead of driving something directly.

The switch will last much longer with low current too.

There is nothing wrong with a float switch, but there are other alternatives, such as optic sensors. If the sensor is wet it also generates a digital signal, and uses 3 wires for the device. I've also messed with my share of ping pong and LED/photosensors to measure fluid levels.

If the OP wants some help a schematic is always nice. Right now we are spitting in the dark.