What Is a Water Detection Sensor?
Water detection sensors are sensors that detect water using long-wavelength light absorbed by water molecules.
General photoelectric sensors can detect most liquids, but since water is transparent, it becomes difficult to detect because of low light attenuation and penetration. Additionally, colored water or water with different color densities is even more difficult to detect because the amount of attenuation changes.
Water detection sensors, on the other hand, use long-wavelength light that is absorbed by water molecules, making it possible to detect transparent water, colored water, and water with different color densities.
Applications of Water Detection Sensors
Water detection sensors are used to detect the presence of water itself because they use long-wavelength light that is absorbed by water molecules. Examples include monitoring water at production sites where water is used, detecting the liquid level of water storage tanks, detecting liquid levels, and detecting whether plastic bottles or transparent glass containers are filled with liquid.
Also, since these sensors can stably detect even atomized water, they are used to monitor spray-based washing processes in business establishments.
Principle of Water Detection Sensor
Water detection sensors, like photoelectric sensors, detect the presence or absence of water by emitting light through a light emitter and receiving it at a sensor. 1.45um (1450nm) long wavelength light is used to enhance the absorption of water molecules.
By using long-wavelength light that is absorbed by water molecules, water detection sensors can stably detect water even in clear water, colored water, and water with different color densities, as the light is absorbed and intercepted by water molecules.
Other Information on Water Detection Sensor
1. Water Detection Sensors With Photo Refraction or Capacitance Detection
Water detection sensors are, in principle, divided into a light emitter and a light receiver, so they must be installed on both sides of the area where detection is to occur. While this is not a problem in an environment where installation space is available, it is not suitable for detecting water in pipes or pipelines in a confined space.
In such cases, compact, light-refractive water detection sensors or capacitive water detection sensors are suitable. Light refraction sensors detect water based on the difference in whether LED light passes through or reflects off the pipe, depending on the presence or absence of water. Capacitance detection sensors, on the other hand, detect the presence or absence of liquid by reading the change in the dielectric constant.
Both only require a single part, can be compactly installed on one side of a pipe or conduit, and can be used in environments where it is difficult to install long-wavelength light types.
2. The Difference Between Water Detection Sensors and Humidity Sensors
Water detection sensors detect the presence of water utilizing long-wavelength light, while humidity sensors use a humidity-sensitive membrane to electrically detect changes in resistance and electrostatic capacitance caused by water droplets between comb-shaped electrodes, and correct for humidity.
The main purpose of water detection sensors is to detect the presence or absence of water. But the main difference is that the humidity sensor can, in principle, detect minute water droplets, so the percentage of water droplets in the atmosphere can be calculated and converted to humidity.
3. Water Detection Sensors in Smartphones
Recently, some smartphone models warn the user when a drop of water is detected on the USB power cord because of the risk of corrosion or deterioration of the electrode during charging. This principle also detects the resistance or capacitance change between the electrodes by converting it into an electrical voltage change.
However, there are still not many models that have such sensors that detect moisture. Many of the temperature and humidity displays often seen on smartphones are based on the identification of the current location using the GPS function, and the temperature and humidity information at that location is obtained and displayed.