I was looking up how battery free pens work and found this.
I was looking up how battery free pens work and found this.
Couldn't find a better community to post this in. :p
Tablet pens are powered by a changing magnetic field generated by the tablet (induction). They only have power when near the tablet.
Some require actual charging so I can see how someone might get confused when switching to a different model
They often have a small capacitor that feeds them and acts as a tiny, couple of minutes long, battery.
That's got to be a really tiny field. I have a remarkable, and can use it for weeks before charging it. Broadcast energy, as you describe, is relatively expensive, because there's a drain whether or not there's an active sink; and even so, that's crazy.
How does that work? It detects the touch of the pen, since it doesn't react to anything else. Is there a conductor on the surface of the screen?
It's probably not on when there's no pen nearby. You can automatically detect those things
What portion of the electromagnetic field is produced by the display?
Do these pens work with tablets that have ePaper displays?
(no experience with these pens; STEM nerd popping in from the main page. I was only aware of styluses <stylusi? styli? styleese?> and battery pens)
Personally I have huion H1060P which doesn't have screen and has battery free pen. The pen is detected some distance from the surface and the same goes for the pressure on the tip and button clicks on the pen. Pretty interesting.