The Research On Self-powered Wireless Liquid Level Sensor Nodes

Sensor is one of the key technologies of the Internet of Things,a large number of sensor nodes will be used in the information perception array,we must design wireless sensor because of the inconvenience of sensors that transferred power and signal by wire,meanwhile,because the battery's life of wireless sensor is limited,it is also important to prolong the working life.Based on the engineering application of liquid level detection,the paper designs the wireless sensor node that transfer data through ZigBee and charge battery through collecting environment energy such as solar energy and heat energy,sensor's work life is extended.The paper mainly focused on three sections: wireless communication,energy collection and sensor node design.In the matter of wireless communication technology,according to the characteristics of the real environment,tested short distance wireless communication technologies,such as Bluetooth,ZigBee and RF,received the characteristic of communication distance and data integrity,determined using ZigBee for data transmission.About energy collection,we experimented the solar energy,heat energy and RF energy,obtained the performance of these methods under the practical condition.In order to effectively use the electricity we collected,using LCT3109,the low voltage booster IC,we designed the power management system,which can work at low input of 30 mV,output stable voltage of 3.2V,4.2V.The circuit can charge lithium battery at a small current,basically satisfy the detection circuit used in low frequency.Finally,using MSP430F149 low power consumption processor,CC2520 and capacitive liquid level sensor,designed sensor node model,realize the liquid level detection sensor which have the function of self-powered battery and wireless communication.