Monitoring long-term uterine contractions

The proposed system for long-term uterine contraction monitoring includes a pressure sensor and a portable monitor. The pressure sensor converts uterine activities into frequency variations from 1 to 2 MHz. The portable monitor is a microcontroller-based embedded system. We chose the 89c52 microcontroller because of its intelligence and functionality. A CMOS counter serves as a frequency down-converter for scaling down the frequency variation from 50 to 100 kHz.