The Development Of A Real-time Monitoring System Of The Water Quality With Extremely Low Power Consumption

At present,the pollution of water quality is increasingly serious and the water quality monitoring results have not been achieved due to a variety of reasons.The use of domestic water quality monitoring systems is limited by electronic processes and manufacturing technologies.Most of them are wired monitoring,and the level of automation is low,which seriously restricts the real-time monitoring of water quality.It is of great practical significance to research a set of real-time monitoring system for extremely low power consumption for wireless real-time monitoring of water quality.This subject has designed a set of real-time monitoring system for water quality with extremely low power consumption based on the actual application requirements.The preliminary design of the system hardware and software nodes and system performance testing has been carried out.The main work and achievements are as follows:1)With the ultra-low power,quad,single supply amplifier design the pH signal amplification conditioning circuit and use it to simulate so that the pH sensor’s output electrical signal range-414mV(pH = 14)to +414mV(pH = 0)the output voltage of the input voltage through the signal conditioning and amplifying circuit corresponds to a range of 1.4V to 0V.2)It is necessary to design a temperature compensation circuit to correct the pH sensor,because that is vulnerable to the effects of temperature.Using the extremely low power,quad,single supply amplifier to build a constant current source and establish a SPICE model of Pt1000 for temperature compensation signal conversion and amplification circuit design,simulation,and the pH of the water at the current temperature can be deduced by the output voltage of the temperature compensation circuit.3)According to the simulation schematic design and production of PCB board for testing,the use of 3V power supply in the actual measurement of the circuit,to attain the circuit with a extremely low power consumption,the total current of less than 130μA;The output voltage of the pH amplifying circuit is transmitted to the PC by using a microcontroller,a Bluetooth,and a serial data line,and the interface is displayed.4)Use the nava-power,zero-drift operational amplifier instead of the ultra-low-power,quad,single-supply amplifier to improve the performance of the simulation circuit;When the voltage is supplied by 3V,the maximum power consumption of the pH simulation amplifying circuit does not exceed 7μA,and the total power consumption of the temperature compensation simulation circuit does not exceed 8μA,allowing the system to work longer.In terms of design,it is achieved with a simple design to achieve the demand,which is conducive to cost savings.This paper points out the direction for further improvement and the improvement of the real-time monitoring system for the extremely low power consumption.