• 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

Electronic optical water level sensor switch is developed on the near-infrared measurement technology. It is a kind of low price liquid level switch without moving parts. The Optical infrared level switch 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 liquid level sensors and optical level switches to measure 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

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 Infrared Optical Water Level Sensors


  • 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℃
  • Rated current: 12mA  (May be different for different model)
  • NOTE: For this models, their function are almost the same,and the main difference is their size and structure. We have several regular models optional,but we can provide customizing design and manufacturing for your project.

Mini Infrared Optical Water Level Sensors

This optical level sensor 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.


  • 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 body,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 to meet your innovation case. 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.

In order to make comparison within the two level switches, we list their advantages/disadvantages as below:

1.Optical level switch has no moving parts to contact level. Magnetic float level switches have to borrows buoyant force to move float ball part up/down,then to trigger reed switch and sense level.And the float ball may be seized to stop by water scale and no-proper installing.

2.Optical level sensor has a small size body and good unity.It can be installed at any direction. However,magnetic float switch is bigger in size and has moving parts.It has a poor unity. It can be only installed at up/down direction.

3.Optical level sensor is not influenced by magnet,heat energy,vibration,etc. But magnetic level switch has a bigger reaction toward magnet and cast iron parts nearby. Its own magnet part will lose magnetism easily influenced by heat energy and vibration.

4.The electronic level sensor can test 1mm above the bottom of water container.Because of float&magnet weight,magnetic float switch needs certain water depth to make it float.As a result,the low level will be influenced. If want lower level,it will have to design a big pit which increases cost and working time.

5.Accuracy of electronic level switch is +/-0.5mm,but float level switch is only +/-2.5mm.

6.Standard life of optical level switch is not less than 50,000 hours. Float level switch is about 10,000-20,000 hours.

By the comparison,you should easily notice that optical infrared level sensors are much better than magnetic float level switch. With our rich experience, we have manufactured the electronic level switches with very high cost-effective solution. Thus, it is your good chance to select our level switch sensor for your project or replace existing unreliable float level switches.