As the Internet of things has evolved recently, construction of smart city infrastructures is also actively proceeding. Smart City is a form in which telecommunication infrastructure facilities are connected to all places in a city like a human neural network to attract new investment and job creation and also to provide high- In a society where people and goods are always connected, and the solution to increase the economic power of the city, the movement of introduction in the whole world including Korea is increasing rapidly. As a result, interest in system, which is efficient for infrastructure management and advantageous for maintenance/repair, will increase. SmartSheet is widely used to protect and monitor underground facilities when building Smart City. The SmartSheet is manufactured in the form of a combination of a communication line and a detection tape used to detect various breakage (damage during construction, breakage due to aging, ground subsidence, sink hole, etc.). This makes it possible to judge whether there is an abnormality through the communication between smart sheets. It is hard to find out exactly where it is when it is damaged underground. Although the damage location can be measured by using the existing TDR, there is a blind spot which can not be measured in the vicinity, and it is also very expensive. In this paper, we design a hardware and dedicated detection program that finds faulty locations within tens of meters to 1km using a low cost embedded board. Circuits and software were constructed by analyzing the relationship between time constant - voltage and impedance. The input values measured by the 10-bit ADC are converted to the correct measurement distance on the table-driven correction algorithm. The proposed system can be applied to location detection such as underground facilities such as piping, road - bridge breakage, plant breakage, and pipeline damage in a building.