Quantum Magnetics has developed an autonomous battery-powered magnetic sensor node for distributed wireless sensor networks. The device digitizes the sensor output signals and transmits data over an RF link using a ZigBee 802.15.4 protocol. The prototype node incorporates Magneto-Resistive (MR) chips configured to measure all three components of the magnetic field, a logic device, analog-to-digital converters, a two-axis tilt sensor, a wireless transceiver, and a set of batteries. For use in outdoor environments, the sensor node is also GPS-ready. At present, the unit measures approximately 4 inches on a side, with about 40% of the volume occupied by the batteries. Using battery power, the node can operate for about 10 hours in a continuous mode and up to 40 hours with a 10% duty cycle. Efforts are underway to develop the next-generation magnetic node with significant reduction in size and part count.