Pen table bought or DYI, or just pencil scribble + photo?

[RoGeorge]

I have some optical mouse sensors, and some low resolution webcams.  Tempted to convert that into an electronic pencil.  Anybody with drawing tablets experience?

There is also the option of buying a Wacom or alike drawing-tablet, though that would take some extra space on the desk + spend some extra money instead of putting to work whatever is already sitting there in the scrap boxes.

Tempted to start a new project rather than buying a ready made device, but is it worth heaving a pen-table device to draw schematics?  Or is it better to just scribble the schematic with pencil and paper, then take a snapshot of it?

[paul@yahrprobert.com]

I recently decided to try finding an electronic diagramming, note-taking setup.  On the software side I found Xournal++, which seems very good for the task.  Then I bought a small Wacom tablet (no screen, just a pen and digitizer tablet, only about $30).  That works but my eye-hand system doesn't let me draw circuits very well.  Then I got a huion kamvas pro 13 off ebay, which is a screen plus a pen.  That setup works pretty well but you have to have a separate computer to plug it into.  I'm on linux and neither Wacom or Huion support it very well but you can make it work.
The reasons why I want to get away from paper notebooks are:
1) As the number of pages grows to be 100 or so you long for a search functionality. On the electronic notebook if I make it a habit of writing my text in little text boxes instead of scribbling it out I can search for words.
2) Adding sections or making major revisions to circuit diagrams is much easier electronically.

What you propose, to develop your own pen system sounds interesting, but are you envisioning using the pen on your computer screen or off to the side like my Wacom non screen tablet digitizer?  If on screen, how will you calibrate the position to line up with the screen coordinates?  Also, are you considering taking the pen coordinates you measure and converting them into USB signals that your software will be able to use?  In the case of Xournal++ on linux you have to get pen movements converted into X windows events, which to me is a rabbit hole I haven't the stomach for.

[RoGeorge]

The problem when trying to draw with a mouse is that the mouse can not be controlled very well.  I assume if an optical mouse were to be grabbed like a pencil, it would be easy to draw.

The idea was to somehow attach the mouse sensor at the tip of a big pencil.  Either by changing the optics from the mouse sensor, or by removing the mouse lens entirely, and replace that with some plastic fiber optic threads, to guide the light from the paper surface to the mouse sensor.  Then, the left-click micro switch should be positioned under the pointing finger, so it can be pressed to draw.  When left-click is not pressed, the "pencil-mouse" will only move the mouse cursor on the screen.

The rest of the electronics and drivers was to remain unchanged, just as if a second mouse would be connected to the PC, except this one will have the shape of a big pencil.

[paul@yahrprobert.com]

So what you propose is very similar to what my Wacom digitizing no screen tablet does.  Maybe that will work for you, but not too well for me.  Using a pen on the screen, so that the "ink" is deposited at the tip of the pen, is a wonderful experience and I hope more devices and software are available for that soon.