This paper proposes a fully reconfigurable universal sensor analog front-end for the Internet of Things era. It is implemented to be able to process different types (R, C, V, and I) of sensor output by using a single input bond pad and a single reconfigurable analog front-end. In addition, a reconfigurable acquisition mode selection method is applied to measure a wide magnitude range of sensor output. Furthermore, the compensation method for the baseline of the sensor is proposed, which can suppress the saturation of the circuit and improve the sensitivity of the sensor output. Also, the correlated double sampling technique is adopted to reduce the low-frequency noise that can affect the sensor output. The proposed system can detect within a relative error of about 1% by using only one input bond pad and analog front-end for the target sensor output range. The proposed system is implemented using TSMC 0.25-mu m CMOS process.