Magnetic sensors/modules detect and measure magnetic fields, providing critical data for navigation, positioning, and electromagnetic environment monitoring. Compass modules specifically determine directional orientation relative to Earth's magnetic field, while general magnetic field modules quantify field strength and variations. These devices are fundamental in applications ranging from consumer electronics to industrial automation and aerospace systems.
| Type | Functional Characteristics | Application Examples |
|---|---|---|
| Hall Effect Sensors | Measure DC/AC magnetic fields via voltage generation across a conductor | Current sensing, position detection |
| Anisotropic Magnetoresistive (AMR) Sensors | High sensitivity to weak magnetic fields (<1 T), low power consumption | Electronic compasses, pedestrian navigation |
| Fluxgate Sensors | High precision for AC fields, excellent stability | Geophysical surveys, submarine detection |
| Magnetoresistive (GMR/TMR) Sensors | Nano-scale sensitivity (nT levels), wide dynamic range | Hard disk drives, biomedical devices |
Typical modules integrate: (1) Sensing element (Hall plate/AMR bridge/GMR multilayers), (2) Signal conditioning ASIC (amplification/filtering), (3) Temperature compensation circuitry, (4) Digital interface (I2C/SPI). Advanced packages incorporate 3-axis sensing and embedded calibration memory. Hermetic sealing with non-magnetic alloys ensures environmental durability.
| Parameter | Description | Importance |
|---|---|---|
| Field Range | Measurement capability ( 25 T to 100mT) | Determines application suitability |
| Sensitivity | mV/ T or T/LSB | Resolution for weak field detection |
| Non-Linearity | Deviation from ideal response (<0.1%) | Accuracy assurance |
| Operating Temperature | -40 C to +125 C | Environmental reliability |
| Current Consumption | 100 A - 10mA | Battery life consideration |
| Manufacturer | Representative Product | Key Specifications |
|---|---|---|
| Honeywell | HMC6352 | 2 T resolution, 8Oe range, I2C interface |
| Infineon | TLE5012B | 360 angle measurement, 0.1 accuracy |
| STMicroelectronics | LSM303DLHC | 3D compass, 16-bit output, 0.1 T sensitivity |
| Bosch Sensortec | BMC150 | Ultra-low power, 0.1 T/LSB resolution |
Key considerations: (1) Match field range to application (e.g., geomagnetic ~50 T vs. motor monitoring ~10mT), (2) Environmental factors (vibration/shock resistance), (3) Interface compatibility (analog/digital), (4) Calibration requirements, (5) Cost vs. performance trade-offs.
Future developments focus on: (1) MEMS-based magnetic sensors with sub- T resolution, (2) Integrated IMU (Inertial Measurement Units) with magnetometers, (3) Energy-harvesting magnetic sensors, (4) AI-enhanced noise cancellation algorithms, (5) Standardization of wireless magnetic sensor networks.