Archive for category Funny

Idea: Virtual treadmill

…maybe that’s not a good name.

The idea is a treadmill-like device that allows you to go in any direction, just just forwards.

Ideally, it would let you go up/down, left/right, forward/back. And more.

A few weeks ago I playing with an Oculus Rift demo where you “pick up” and move around cubes with a hand/finger position sensing glove.

I remarked that the cubes were awfully light – must be made of aerogel or something.

Which I guess says the illusion of reality was pretty good.

That got me thinking about what a real VR environment might feel like.

The first obvious thing that’s missing is the ability to walk around naturally.

A treadmill-like platform that can move in 2 axes (instead of 1 like the usual treadmill, or 1 plus angle) would be nice, but I couldn’t think of a way to make it work mechanically.


But what you could do is make a pair of servo-driven harnesses, one for each foot. They’d be attached to boots that you’d put your feet in.

Within a limited volume (as much space as a foot can reach from a single position), each harness would be able to move the boot (and resist movement) thru 6 degrees of freedom:

  • X, Y, Z
  • Pitch, roll, yaw

It would be able to resist movement to simulate friction, climbing, etc., and to move at various speeds to simulate walking, running, sliding, etc. Each of the 6 degrees of freedom would be controlled by a servomotor and connected by linkages (pretty straightforward mechanically; requires competence but not invention).

Of course it would have limits, but I think you could use this to create a “pretty good” feeling of walking around, running, even jumping.

For example, suppose you want a VR environment that simulates lunar gravity (1/6th g).

You can’t change the force with which gravity pulls you toward the floor, but if you “jump” (a vigourous downforce on the boot), you’d measure the force of the jump and plot the jumper’s ballistic trajectory. While “in the air”, all resistance to movement (all 6 degrees) are turned off – so the user feels he can wiggle his feet around as if floating. When he “lands” there’s a sudden locking of the pitch/roll/yaw axes and a sharp jerk in the +Z direction (if he lands upright).

Main applications would be VR exploration, exercise games, FPS games, etc. If the experience feels right I think there could be a mass market for the things. In any case, there’s a small high-end market that could (and should) be pioneered first.

The next step is to make another pair for the hands, maybe even with actuators for each finger joint…

Yes, you have my permission to use this idea. My usual terms apply.

A big number

I’ve been reading Edward Teller’s autobiography.

In a footnote (p. 247), Teller mentions that “the electron in a hydrogen atom will eventually jump to a proton if it is close enough”.

Teller and Francis Owen Rice calculated how long it would take, if the proton is 1 centimeter away.

Their answer was 10100,000,000.

A long time. A “big number”.


That’s the same as 10108, which is more than a googol (10100), but much less than a googolplex (1010100).


What’s that? You want to know what units?

You mean is the 10100,000,000 in Planck times (5.4 x 10-44 seconds), or seconds, or years, or time periods since the Big Bang?

Doesn’t matter. (Think about it.)

That’s how big a number it is.

Am I the only one who thinks this is funny?

The Economist, 2009-09-12, US Edition (Georgia)

The Economist, 2009-09-12, US Edition (Georgia)

Naked proton

Two hydrogen atoms meet.

One says, ‘I’ve lost my electron.’

The other says ‘Are you sure?’

The first replies, ‘Yes, I’m positive.’