Design And Implementation Of Water Purifier System Based On NB-IOT

In recent years,the health of drinking water has been paid more and more attention,and the water purification industry is booming and developing.Most of the water purification products are achieved by passing the water through multiple filter elements.The main problems of this kind of products are as follows: 1.Users can’t easily know the effect of water filtration;2.Manufacturers can’t get real-time information about the use of equipment and can’t provide timely replacement of filters 3.The service life of filter element can not be calculated accurately without considering the difference of water quality in different areas.From the perspective of improving the detection method of water purification effect and remote operation and maintenance of the system,this paper proposes a set of system based on NB-IOT(narrow band Internet of things),The water purifier system improvement scheme is composed of TDS(total dissolved solids)value detection node with temperature compensation,water flow sensor node,NB wireless communication controller,MCU main control board based on uC//OS-Ⅲ system,and app to obtain information.During the operation of the system,the total amount of water purification is updated in real time,and the service life of filter element is adjusted by combining the dual TDS value.The local calculation and storage of water consumption information and the remaining life of filter element consumption reduce the amount of data uploaded to the cloud and the amount of calculation in the cloud.App obtains the water purifier information,which brings users data transparency,intelligent control and easy operation.In the water purification system,the TDS probe will produce polarization effect and equivalent capacitance under long-term power on in water,which will affect the accuracy of TDS value detection.This paper proposes a method based on multi frequency bipolar,which dynamically adjusts the PWM frequency and duty cycle applied to both ends of TDS probe through the detection results,corrects the conductivity coefficient corresponding to different temperatures by temperature compensation,and obtains the results through filtering Wave algorithm.The feasibility of this method is verified by experiments.The TDS value of standard purified water is10 ppm(parts per)The results show that the TDS value of purified water is stable in the range of4ppm-6ppm with millet TDS detection pen as reference;under the premise of polarization effect and equivalent capacitance,the TDS value detected by this system is more than 20 ppm,and the comparison error is large;multi frequency bipolar method is used to neutralize the single end of TDS probe,only positive In the case of charge or negative charge,the influence of polarization effect and equivalent capacitance on TDS acquisition error is weakened.Temperature compensation and filtering processing make TDS value more stable.The TDS value of purified water is basically between 3ppm and 5ppm,and there is no sudden change.Due to the wide distribution of equipment sold in different regions,and the size of equipment distribution in the same region is different,the success rate of remote firmware upgrade due to the high concentration of regional communication data is greatly reduced in the case of high concentration of equipment.A centralized large-scale NB-IOT terminal upgrade method is designed.The cell base stations accessed by the equipment are numbered.Based on the idea of sliding window,the number of concurrent terminal upgrades is dynamically predicted by making full use of limited bandwidth.According to the actual simulation,compared with the fixed concurrency value,the average success rate of single batch upgrade is increased by 30%,which greatly reduces the probability of the first upgrade failure and the second upgrade attempt.