Abstract: The present invention is a magnetic field warning device suitable for protecting fetal health by alerting the mother whenever she or her fetus is exposed to alternating magnetic field levels which exceed predetermined levels. The device may also be used by anyone concerned about exposure to excessive alternating magnetic fields. The device comprises a magnetic field sensor for sensing alternating magnetic fields of arbitrary orientation, a detector for obtaining the magnitude of the sensed magnetic field, a filter for reducing the possibility of false alarms, a comparator for comparing the magnitude of the sensed field to a predetermined magnitude, and an alarm mechanism. The predetermined magnitude may optionally be adjustable, and the alarm mechanism is designed to minimize unwanted coupling of vibration to the user's abdomen. The device may be made small enough to be easily clipped on a belt so as to be worn by pregnant women at the abdominal level to monitor magnetic field exposure at the abdomen.

Abstract: The present invention is a maternal sound level device that functions to protect fetal hearing by alerting the mother whenever her fetus is exposed to sound pressure levels (SPL) which exceed predetermined levels. The device is comprised of a microphone (14) for SPL detection, preamplifier (2), weighting network (4), level detector (6), and alarm mechanism (8). This device is battery operated and can be easily clipped on a belt so as to be worn by pregnant women at the abdominal level to monitor SPL at the abdomen. SPLs are measured in the range of greater than 80 dB and less than 100 dB over a frequency range of greater than 30 Hz and less than 10,000 Hz. The mother is alerted to SPLs that are exceeding a predetermined level to protect the hearing of the mother's developing fetus by a visual and/or a mechanical alarm.