Magnetometer for Davide Boriani’s Kinetic Sculpture

Behind the façade of Davide Boriani’s Magnetic Sculpture is a series of magnets that rotate on 2 axes. Because the magnets are dragged against the sculpture façade’s metal backing when in operation, it is likely that the magnets have lost their strength. Factors such as heat, erosion, and disruption of domain orientation from interfering magnetic fields can result in loss of magnetic strength and could contribute to the sculpture’s current state of malfunction. Though the original and intended strength of the magnets is unknown, measurements can be taken from the magnets in their current state and be compared.

For more information on how magnets work, listen to this episode of Stuff You Should Know.

Magnetometers are tools that can measure the direction and intensity of a magnetic field. Magnetometers—also known as gaussmeters— are used in several common devices such as metal detectors, health hazard detectors, and digital compasses (they also have ghost-hunting applications!) Magnetometers that report strength and orientation are relatively expensive ($150-$500+) but sensors can be incorporated into integrated circuits for less than $5. I used my Arduino Uno R3 to set up a cheap magnetometer using the MLX90393 Wide-Range 3-Axis Magnetometer breakout sensor according to these directions.

I measured each magnet’s strength with the Arduino magnetometer hoping to find irregularities or outliers that might suggest demagnetization. Within each pair of magnets set in the brass wells and guards, there is one magnet that attracts and one that repels. The data shows that the attracting magnets’ average strength was 17,008μT or 170 gauss and the repelling magnets’ average strength was approximately -17,024μT. For reference, the magnets incorporated in Magnetic Surface are closest in strength to a strong refrigerator magnet (about 100 gauss). The intensity of each magnet is relatively the same, therefore I don’t have sufficient proof that the magnets have lost their strength.