My apologies for the delay in getting these pictures up: actually taking the pictures turned out to be trickier than I had expected, and in the end I had to borrow the portable photo booth that my husband uses to take pictures of his model tanks (thank you, darling!).
However, here we are:
Get your piece of conductive foam:
And your Q-tip:
And your mechanical pencil:
Trim the Q-tip stem:
Glue the foam to the end of the plastic tube, and trim to shape:
Insert into jaws of mechanical pencil, and you're done:
I've managed to get hold of some Sugru, and I want to see if I can improve on this stylus by capping the end of the tube with a blob of Sugru before adding the foam. If that works, I'll post about it.