Abstract:In order to solve the task of monitoring and regulating the water flow of urban pipe network in the construction of smart city, a water velocity and flow measurement instrument based on Internet of things is designed, including ultrasonic Doppler velocity probe (with temperature correction), battery and charging part (power monitoring), GPRS module, interface button, LCD, extended serial interface and STM32F103 main controller At the same time, the web page can also view the real-time and historical flow rate, flow and liquid level data of nodes. The results show that the measurement data of the three methods confirm each other, and the error is within 3%. It is concluded that the instrument has high automation and measurement accuracy.