Gas sensors always have cross sensitivity

and the precision of traditional compound gas detection is low and time consuming is long. A multi component gas monitoring device based on freld programmable gate array（ FPGA） is designed

which is based on the gas sensor array. A hardware neural network controller is designed on the FPGA to fuse the multi-sensor data. Among them

the Sigmoid function is an important part of the hardware to realize the neural network

and the hardware Sigmoid function is implemented on the FPGA through the method of subsection fitting and pipeline design. Simulation and application show that the device has the advantages of high detection precision and fast response

and has good scalability.