• Simple structure,higher accuracy,longer life
  • Compact body can be installed at any direction
  • No moving parts,almost no influence to fluid
  • High sensitivity,no need to adjust,easy to use
  • Patent  design with low power consumption
  • Good chemical stability:High  temperature resistance, high pressure resistance, corrosion resistance
  • Compliance with ROHS and  safety rules
  • Ideal to replace float level switches and electrode level sensors

Optical Level Sensor Intro:

Infrared optical level sensor is developed on the near-infrared measurement technology. It is a kind of low price liquid level switch without moving parts. The Optical level sensor is an innovative level measurement solution.It is used for point level monitor and level sensing.It has been widely used for water dispenser,water heater,humidifier,spa device,medical devices,lab instrumentation,other industries for level detecting,etc.

We supply wide range of infrared optical level sensors and optical level switches for high accuracy liquid level measurement and typical including water,oil,etc. It is used for point level detecting and can monitor high/low level.We have common purpose version for clean liquid with low viscosity, and have other versions for special applications. It is NOT used for Easily crystallized liquid or freezing liquid. With patented electronic processing technology, part of our optical level sensors have been widely used to replace similar product of Honeywell,Gems,etc.

Working Principle of Optical Level Switch Sensor

The  optical level sensor contains a near-infrared light-emitting diode and a photosensitive receiver. The light by light-emitting diode is led to lens on the head of sensor. When liquid immerses the lens,light is refracted into liquid,as a result, receiver can't get light or less. Just by sensing the situation changing, receiver can drive inner photoelectric switch for open outer alarm/control wire loop. If there is no liquid, light by light-emitting diode will be directly refracted back to receiver through the lens.

Typical Application

  • Sanitary appliance,Pump,Bathing
  • Water Heater, Humidifier,Water dispenser
  • Medical equipment and instrumentation
  • Analytical instruments, Lab instruments
  • Oil level monitor of Compressor and others in refrigeration system
  • Key level monitor of industry application
  • Other electronic level monitor without moving parts

Low Price Miniature Optical Water Level Sensor

The series optical water level sensor is specially designed for water level measuring and monitoring. They have miniature integrated type structure with high cost-effective solution. It has been widely used for electronic toilet, water heater,water dispenser, bath,pump,medical facilities, sanitary appliance, humidifier,and other electric appliance that requires water level monitoring.


  • Power supply: 5VDC
  • High accuracy(level):+/- 0.5mm
  • High/low electric level output:low output<0.1V,high output>4.6V (May be different for different model)
  • Working temperature: -25℃~ +65℃(NOT used for Easily crystallized liquid or freezing liquid)
  • Storing temperature: -30℃~ +80℃
  • Protection Class: IP65-IP68 (Decided by different models)
  • Rated current: 12mA  (May be different for different model)


1.In this models, their function are almost the same,and the main difference is their size and body structure.

2. There have been fake imitation items in the market,but they may not be able to master reliable technology. Please be cautious!

3.We have several regular models optional,but we can provide customizing service for your project.

Ultra Mini Optical Liquid Level Sensor Switch

This ultra miniature optical liquid level sensor switch has a micro structure with size of a 5mm diameter LED. The whole length is about 9mm and diameter is 5mm. It is embedded installing way with simple wiring loop. It is encapsulated with epoxy resin and the output is transistor E pole. Small size body make it more suitable for various of space and can be used for analysis instrument,lab instrument,small size container and level detecting, alarm and monitor in pipe.

This model is specially designed for liquid level detecting at extreme small installing space and it can also be used for level monitoring of small volume liquids. It is manufactured with professional and comlicated technology to ensure its stable performnace. It has been widely used for clean non-crystalline liquids with low viscosity. And the typical liquids mainly have lubricating oil, gasoline, diesel oil, edible oil, all kinds of drinking water and beverages, acid, alkali, salt solution and various organic solvents except acetone, etc.



  • Power supply: 5VDC
  • High accuracy(level):+/- 1.0mm
  • Embedding depth: 3mm-5mm
  • Material: Wholly encapsulating with metal rack and epoxy resin
  • Working pressure: -0.1 to 2.5MPa
  • Working temperature: -25℃~ +65℃(NOT used for Easily crystallized liquid or freezing liquid)
  • Impact of voltage: C-E>=10VDC;C- ‘-’ 1.8-2.5VDC
  • Output way: Transistor E pole
  •  Current consuming: 15mA
  • Wiring terminals: switch value: 3 nos, power(0,V+), signal source(E);


Main Application

For clean amorphous liquid with low viscosity on analysis&lab instrument devices(e.g.,oil, gasoline, diesel; edible oil, all kinds of drinking water and drinks; acid, alkali, salt solution and a variety of organic solvents except acetone,etc).It can be used for liquid level key point, up/down limiting point, and monitoring,display alarm & certain point controlling of multi-point level.

Basic Application Wiring Diagram

(When 5VDC power supply,R1=510 ohm,R2=6.8 K ohm, it will get better output effect.)

Body Structure Explanation

Infrared optical water level sensors are usually integrated type with small size,but we also provide separated type optional. The separated type optical level sensor has the following advantages:

  • Make control wiring part is apart from water container. Meanwhile, its sensitivity,accuracy and working life is not influenced.
  • Improve fault-tolerant rate.Even though there is deviation between water container and  sensing parts,the level sensor switch can still work well within allowed range.

Customization Service

We know your requirement may vary, which is decided by different project. We can provide customization service for optical level sensors to meet your special requirement. Please feel free to contact us for more details.

Idea Solution to Replace Float Switches and Electrodes

Float switches are widely used for simple water level controlling because it is simple and cheap. But they have many problems and you may often find they can't work well,then water flows around from containers to cause big loss for your materials. That's because float switches need to use reed switch as action parts to monitor water level. However,because of frequent actions, reed switches are not reliable. Meanwhile, float switches are usually immersed in water or other fluids, this condition will further worsen working status of float switches and make them become faulty from time to time. This will waste your money, and the main is that may delay your working and your expensive time.