Introduction of various types of sensors in smart home appliances
Previously, sensors were mainly used in temperature control and level control systems, and their functions have now improved:
1. Basically, a negative temperature coefficient (NTC, Negative Temperature Coefficient) and a positive temperature coefficient (PTC, PosiTIve Temperature Coefficient) thermistor are used in all temperature measurements;
2. Measure the residual humidity with an inductive sensor;
3. Measuring the rotational speed of the washing machine and the dryer with a rotational speed sensor;
4, the capacitive sensor is applied to the button switch operation;
5, integrated temperature sensor indicates engine overload.
In recent years, new and improved miniature sensors have been used in washing machines and dishwashers.
(1) Pressure sensors are used as water level switches or more complex devices, such as monitoring of foam levels in washing machines and dryers.
(2) Chemical sensors are used for water quality monitoring. Monitoring parameters include turbidity, color, surface tension, detergent solubility, pH, etc., and then the number of rinse cycles (solution sensing system).
(3) The photoelectric system is used to monitor the turbidity of the washing machine so that the number of flushing cycles is consistent with the actual needs (aqueous agent system).
(4) The electromagnetic sensor is used in the dishwasher to control the movement of the spray arm.
Advanced sensors are also used in many other appliances.
(1) Non-contact detection system. For example, a micromachined thermocouple infrared sensor for temperature control, which can also be used in cookware, hair care appliances and toasters.
(2) Flow sensors can be used to detect air quality in electric fans and vacuum cleaners.
(3) Acceleration and slope sensors can be used in electric arcs.
(4) Intelligent multi-gas sensor (artificial nose) can be used in automatic accompanying baking control.
Sensors for heating and temperature control are: Temperature sensors and switches, pressure sensors and switches, gas and liquid flow sensors. Temperature control is one of the earliest established and most important functions in home appliances. A good example is the uranium resistance temperature sensor based on advanced film fiber technology, which is commonly used in kitchen hot plates and ovens.
The reed switch is a typical example of long-distance sensing technology. It is used in thousands of electrical equipment.
Applications of reed technology include:
1, the turbine meter measures the liquid flow;
2, water level monitoring, for example in a coffee machine, or in a dishwasher to monitor the water level of softeners and clarifiers;
3, the movement control of the spray arm of the dishwasher;
4, washing machine drum position detection;
5, safety control of electrical door detection;
6, electric toothbrush;
7, the reed sensor in the carpet vacuum cleaner;
3, massage chair, bathtub lift and the movement of the hospital bed or the detection of the final position.
Take some new or improved sensors for smart small appliances as an example.
(1) The combination of sensors and non-contact temperature dispersion identification can be used for automatic baking control. Long-distance non-contact temperature, humidity, and color detection for hair care devices.
(2) Smart medical sensors are used for protective equipment. An improved UV sensor is used in the device as a protection against allergy to UV light.
(3) Intelligent shoes can use the acceleration sensor to measure the movement of the footsteps, and also calculate the distance between the runners and the walkers.
(4) The distance sensor and pressure sensor are used to adjust the blade during use of the razor.
(5) In many kitchen appliances, some sensors can be used to implement automatic cooking functions, such as determining the state of the food and monitoring for possible accidents.
(6) Some sensors can be used to operate the vacuum cleaner from a distance. More applications of sensors in home appliances are shown in Table 1.