With time, sensor technology is taking more and more important part in our daily life. Sensor faucets, sensor urinal flushers, sensor toilet flushers, sensor soap dispensers and so on. Before we adopt the sensor technology into these products, they are normally operated by hands push, pull or rotation.

What are advantages of these sensor products? First of all, they are cool! They are different from traditional types and it is a symbol of modern. It also helps us to keep healthy by avoiding bacteria without touching the handles or buttons. And it also helps saves water. Take sensor faucets as an example, the water only comes out when there are objects detected, it means water will stop automatically when the users move their hands away. Products with sensor technology normally cost more than manual type, but sensor products have a longer lifespan as it avoids damages of violent operations or misoperations especially in public places.

What are included in the sensor technology? Let’s take sensor faucets as an example again. There are mainly three parts, sensor, solenoid valve and power supply.


The sensor is a detector of the faucets. It detects the presence of hands. When hands get into the sensor range, it sends a signal to the solenoid valve to turn on the water and when hands get out of the sensor range, it sends a signal to solenoid valve again to turn off the water. There are 3 important points when selecting a good sensor.

  1. Good faucet sensors are all sealed with glue with strong water proof feature. It is the basic requirements to have the sensors with a long lifespan working in different environment.
  2. Stable sensor range is very important to a good sensor and which is often neglected by new purchaser of sensors. The sensor distance is sensitive to environment, sunlight, temperature, microwave around, interference from main power and so on. The influence can’t be eliminated completely, but it should be controlled in a range. And in some poor sensors, the sensor will stop working directly when they get interferences.
  3. Energy saving. Most of sensor products accept battery power supply. What a bother will it be if it need replacement or recharging often? A good sensor should be energy saving and with low power alert to indicate.

Solenoid valve

Solenoid valve is the part to control the water flow. When it receives signals from the sensor, it will change the status to let the water flow or stop. The tests to solenoid valves are mainly about function performance at high and low water pressure. Some solenoid valves have a narrow range of water range, when the water pressure is out of the range, the solenoid valve stops working. That will not meet some standards and it will be a lot of work to replace them when they have gone into service. And according to different appliances, the type of solenoid valve and the material should also be taken into consideration.

Power supply

There are mainly two types power supply, battery and main power.

As for battery power supply, it is usually alkaline batteries or lithium batteries. Replacement and recharging should not be forgotten. So when sensor products don’t work suddenly, first check the battery supply.

Another type supply is the main power. With it, you don’t need to care about replacement or recharging. But it will not be suitable for places with power cut off often.

There is also a third choice which is taken most is to have both battery and main power supply. When main power available, it will use main power. And when the main power is cut of, it will transfer to battery power automatically to keep the faucet working all the time.


Rajeyn has been in designing and developing sensors and sensor systems for more than 15 years. Welcome to contact us if you need our support. You can also contact sales3@rajeyn.com, +86 1775012712 for a quick response.