What is a magnetometer and how does it work?
Among the MEMS sensors included in the Botland shop's offer, you will find devices with a built-in gyroscope, accelerometer, as well as magnetometer - a device used to measure the strength of a magnetic field, usually based on the Hall effect or the phenomenon of magnetoresistance. In a Hall magnetometer, if we connect a voltage source to a metal plate, we induce a current flow between the two surfaces of the plate. When a source of magnetic field (e.g. a magnet) is brought close to a plate supplied with DC voltage, the flow of electrons on the surface of the plate is distorted. Then, one side of the plate will be occupied by electrons and the other side by protons. If we connect a voltmeter between both surfaces of the plate, we will be able to read the voltage whose value depends on the intensity of the magnetic field and its direction in space. The magnetoresistive concept of the magnetometer, on the other hand, uses materials that are sensitive to magnetic fields - iron-nickel alloy is often found. Such materials change their resistance when exposed to a magnetic field. MEMS sensors available in our offer are also equipped with I2C interface, so you can easily connect your magnetometer to work with e.g. Arduino or Raspberry Pi.
Magnometer in your phone - MEMS Gyroscopes - small and practical
If you want to develop your robot project in terms of its equilibrium stability when stopping, moving or standing still on an uneven surface, a great solution would be to use a small MEMS gyroscope, which, by measuring the robot's angular deviation from its equilibrium position, would send information to Arduino, which, by controlling appropriate motors and servos, would set the robot in the right position, preventing it from tipping over. And how is the angular velocity measured by the MEMS gyroscope? The sensor built into these devices is no bigger than the diameter of a human hair and works on the basis of the phenomenon of mechanical resonance. When the gyroscope is rotated, the MEMS sensor converts this movement into a very low-level voltage signal proportional to the angle of rotation. This signal is then amplified and transmitted to a microcontroller, where further decisions are made via software depending on the voltage value read.
Accelerometer - easy acceleration measurement
Accelerometers are devices whose task is to measure acceleration - a quantity describing how quickly the speed of an object changes over time. Accelerometers are helpful tools in measurement systems to detect vibrations of the test object and in navigation systems. An accelerometer detects the static and dynamic effects of acceleration. Static forces include gravitational interaction, while dynamic forces include vibration and displacement. Accelerometers can measure acceleration in one, two, or three axes of a coordinate system, but as with gyroscopes, a three-axis solution is prevalent. A typical accelerometer consists of microscopically small electrodes forming a capacitor and suspended on springs. Under the influence of the acceleration, the electrodes move in relation to each other changing their capacitance - the speed of these changes allows to determine the acceleration of the object, on which the accelerometer works. There are also piezoelectric accelerometers, in which a suitable material under the influence of mechanical action, creates an electric charge on its surface - this phenomenon is used, among others, during seismic measurements.
