The Digilent device integrates the digital compass IC with a circuit that allows the user to read the three ADC’s value using I2C, one of those many serial protocols to exchange data.

Common NMR (Nuclear Magnetic Resonance) apparatus use magnetic field of the order of 1-1.5 T. The average geomagnetic field, exploited by mariners using magnetic compasses, has an intensity of about 0.5 G, i.e. The standard unit is the Tesla (T): 1 T correspond to 10000 G. The symbol G stands for Gauss, one of the units to measure magnetic fields. Thanks to its 12 bits ADC’s, it provides a very good resolution of 2 mG, and can measure fields up to 8 G. The digital compass is a chip embedded, as usual, in a box and measures the intensity of the magnetic field along the axis aligned along its edges, using the principle of magnetoresistance, briefly illustrated in the previous post.

Usually those axis are taken as orthogonal to each other. it has three components that can be measured along three non parallel axis. The device uses the HMC5883L digital compass IC from Honeywell to measure the three components of a magnetic field along three orthogonal axis.Ī magnetic field is a vector field, i.e.

In this post I’m going to illustrate the usage of a digital compass, namely a device from Digilent called PmodCMPS, to measure the intensity of a magnetic field. Such sensors, then, can only tell you if there is a strong enough magnetic field close to the sensor or not.

A digital sensor provides just two states: on and off. My previous post was devoted to the illustration of a digital magnetoresistive sensor.

Arduino wire library read word command