How to avoid chatter in a reed switch keyboard?

Question

Electronics

Causes of interference:

1. EMF induced by the movement of a magnet
   
2. EMF induced by the movement of reed switch contacts in a constant magnetic field
   
3. Magnetostrictive effect
   
4. Contact noise
   

For example, in order to avoid the magnetostrictive effect in point 3, an alloy of iron and nickel (45-82% Ni) can be used. The alloy has almost zero magnetostriction.
And what should be applied in other points to avoid or minimize them?

Answer 1

use switchable reed switches and RS flip-flop.

Answer 2

1. The EMF induced by the magnet is negligible, so you need to pull up to + 5V so that the level change when pressed is many times greater than the change associated with the action of this EMF.
2. EMF is also negligible, but it has a pulsed character - when using a pull-up, its effect will also decrease.
4. The correct choice of resistance in the pull-up circuit will also reduce noise (due to capacitances in the power circuit), but you can also add a 5 ... 10nF capacitor to suppress noise.