Quote:
Originally Posted by fogice
The magnet is here on the Libra 2. I successfully used aluminum foil folded to be 8 layers thick behind this spot.
I'm also curious to know how the sensor works. |
It's not a magnet. It's a transistor like device that's sensitive to a magnetic field. It's called the Hall effect, so they are sold as Hall Effect Sensors. They are about half the size of a match head.
A piece of card or plastic will work as well as aluminium foil, as it's just the spacing.
Before the Hall Effect Sensor was perfected as a commercial device the simplest magnet operated switch was the reed switch. The smallest ones are slightly bigger diameter glass tube than a match stick, and about half the length, with the two metal reeds inside that contact if a strong enough magnet is close enough. Still used as sensors on doors and windows for burglar alarms till recently.
Some ereaders do have magnets inside to act as a catch for a cover. This is a stupid idea (loads in a Sage) because the magnets may cancel the sleep cover magnet of a second eink, phone or tablet when stacked on a table or in a bag. These are stronger magnets than the small one in a cover to operate the Hall Sensor device in the eReader, phone or tablet.
Gory technical details that are mostly correct. I have a bunch of the sensors in a drawer that look like little plastic cased transistors for "projects". A reed switch is bulky and fragile. The Hall Effect sensor can give a variable output so can bed used even for a contactless throttle on an electric scooter or machine as well as to compare magnets.
https://en.wikipedia.org/wiki/Hall_effect