What kind of liquid? What kind of application (e.g. vehicle, appliance, laboratory)?
Without knowing anything else, I would propose a hydrostatic pressure sensor at the bottom of the tank. BTW, this article has a good list of principles used for level sensing: https://en.wikipedia.org/wiki/Level_sensor.
1. Is the tank fixed ? If it's moving and possibly with vibrations, the problem will
be more complicated and even a pressure sensor as suggested above will not
be simple.
2. Can the liquid conduct electricity? If yes, only 2 electrodes can make it.
3. Do you need a linear measure of the liquid or a threshold below which for
instance a LED will blink?
ETC...
Dora.
pepakpan said:
Hi
I am looking for a sensor which can measure low level of liquid in 250 ml tank and send signal to controller. which has to be cheap and small in size.
thanks for the reply. I am looking for a sensor which can be mounted on bottom of the 250ml bottle. The bottle contains Oil. The sensor has to give signal when the liquid level is low. This bottle bottom side is mounted on another surface so i need a solution where the sensor with bottle can be removed and mounted again or disposed.
Which pathes are available to access the "bottle" inside? If you possibly consider a "through-wall" measurement, what is the container's material and thickness? Do you have fresh oil or must we expect mud and particle deposition at the sensor or the container wall?
If I correctly understood that a low level indicator is required, than a self heated PTC is the most simple solution. Capacitive sensors and total internal reflection sensors (as Honeywell LLE series) are others.
yes you are correct, I am looking for low level indicator but it should be small in size and less in price because i need to mount this on 250ml oil tank.