Drawing tablets have been a favorite computer of artists since its inception in the 1980s. If you have ever used a drawing tablet of this nature, you may have wondered, how it works, and if you can make one. Well, wonder no longer as [Yukidama] has demonstrated an open source electromagnetic resonance (EMR) drawing tablet build!
The principle of simple EMR tablets is quite straight forward. A coil in the tablet oscillates from around 400 kHz to 600 kHz. This induces a current inside a coil within the pen at its resonant frequency. This in turn, results in a voltage spike within the tablet around the pen’s resonant frequency. For pressure sensing, a simple circuit within the pen can shift its resonant frequency, which likewise is picked up within the tablet. The tablet’s input buttons work in similar ways!
But this is merely one dimensional. To sample two dimensions, two arrays of coils are needed. One to sample the horizontal axis, and one the vertical. The driver circuit simply sweeps over the array and samples every coil at any arbitrary speed the driver can achieve.
Finally, [Yukidama] made a last demo by refining the driver board, designed to drive a flexible circuit containing the coils. This then sits behind the screen of a Panasonic RZ series laptop, turning the device into a rather effective drawing tablet!
If tablets aren’t your style, check out this drawing pen.
Thanks [anfractuosity] for the tip!
This is absolutely amazing, love it!
Professional pen displays cost an arm and a leg.
This is a super cool project… It’s very cool to see how this works, I didn’t really understand this technology before
The pen displays typically do cost a fortune, but the smaller pen-only ones are surprisingly reasonable.
https://estore.wacom.com/en-us/tablets.html
I’m also really impressed by recent tablets (like Samsung Galaxy tab) that can also be used as great wireless pen input displays, for a few hundred dollars.
I’m in animation and I can tell you that not a single persin in our field likes samsung tablets and most no longer care for ipads either.
When you get a job you’re typically handed a cheap huion pen display and most of us just use those now in our OS of choice — including android if our phones have dp apt mode out.
Samsung pen tablets have serious jitter issues in conjunction with an overly aggressive “smoothing” algorithm meant to correct for that and its extremely annoying to use.
especially funny when the maker claims that it is actually cheap while demonstrating the pen under oscilloscope.
wacom, scammy
This is awesome! Now I want to build one for myself! :-D
Now hold a magnet or ferromagnetic metal object.near the touch sensor
Watch it go crazy
Maybe be able to actually directly capture magnetic field lines
B.S. You clearly have not tried this.
A static magnetic field doesn’t affect them.
A big hunk of steel nearby doesn’t affect them.
line-frequency AC fields don’t affect them.
They can’t see through a sheet of metal, but that’s kind of expected.