Making a pen for a digitiser tablet - calcomp DB3

[Alex Bird]

I had some success making a pointer device for a trust digitiser last
year. I didn't actually need one for that device, I was using it for
investigation.

The tablet I need a pointer for, because they're very expensive to buy,
is a Calcomp DB3. When I came to investigate this board, I couldn't
find the HF signal to feed the pointer as in the trust device.

Of course it's possible the calcomp doesn't work, I got it in an
auction with some other kit 10 years ago!

Anyone have any experience with these?

Cheers,
Alex

 

[stickyfox@gmail.com]

I think the puck is just a receiver maybe with an amplifier in it, and
the board itself generates the field. How does the trust pointer work?

 

[Alex Bird]

stickyfox@gmail.com wrote:

I think the puck is just a receiver maybe with an amplifier in it, and
the board itself generates the field. How does the trust pointer work?

Nope, the trust and calcomp work, like all these devices, by a grid of
wires (pcb lines these days) which pick up a magnetic field from a
small coil in the pointer device. They locate it by the wires picking
up the most signal.
I don't think it could really work the other way around.

Cheers,
Alex