CONSTRUCTION OF MAGNETIC GRADIOMETER USING FGM-3 SENSOR, INTEGRATED CIRCUIT SCL007 AND MICROCONTROLLER ARDUINO

• Main Author: GERMANNDAPUTRA SULISTYANTO (NIM: 12312061), ARNO
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/21256
• Institution: Institut Teknologi Bandung

Geomagnetic survey has been widely used as initial exploration for mining and geothermal purposes, archeological expedition and military purposes as well. Geomagnetic method uses magnetometer to measure the magnetic properties of a region. Gradiometer uses two fluxgate sensors FGM-3 that are connected to an integrated circuit SCL007 which especially made for gradiometer configuration. The configuration of gradiometer is by positioning two sensors in the same direction and orientation in a certain distance, so that the value of two sensors will cancel each other out with the assumption that there are no anomaly around the device. In case of an anomaly near the device, the nearest sensor will generate different value than the other sensor, therefore there will be a difference that reflect the magnitude of the anomaly. The output of this device is in voltage which is in volt that later will be converted into magnetic field strength in nanotesla with the process of calibration. The calibration is carried out by injecting currents into two solenoids surrounding the sensors. This calibration process will produce a chart that compares the changes of magnetic field strength and the changes of voltage. The chart will show the linearity that indicate the work area of the instrument. The result shows that the instrument can work and has a wide work area that also complements with the increase of audio frequency emitted by the instrument. There is a defect in the construction of the instrument that the sensors aren’t aligned with one another, therefore the two sensors aren’t detecting the exactly same magnetic field.