Come spegnere le calamite

One magnet piece is composed of  “1 permanent magnet + 1 electromagnet”. 

The permanent magnet stick the kid to the chair (it always work, 7 days a week, 24h a day, for more than 40 years).

When we activate the electro magnet, his magnetic fields compensate the permanent magnet field.

At the top, when sensors are in contact with the 24V brushes, electricity goes to the electro magnet and activate it.

As long as the sensor is in contact with the brushes, elctro magnet is activated, the 2 fields cancel each other, and the kid can get of.