Wall cimbing with electrostatic forces

Totally cool. It should be easy to build one. I wonder what voltage it uses on the pads?

Batman and Spiderman better watch out!

On a sunny day (Fri, 23 May 2008 09:16:08 -0700) it happened "Bob Eld" wrote in :

Probably high, they mention switching times of Batman and Spiderman better watch out!

Yep!

Sounds like a spin-off from the Scanning Tunnelling Microscope. Alan

Y'figure, a grid of wires embedded in a sheet of silicone? The wires alternate so like a 'fridge magnet, each pair of wires generates some force. (In case you haven't noticed, those flat flexible 'fridge magnets are made with alternating N-S layers. You can take two and slide them across, they cog as the N and S's oppose.)

Then you could use a couple of these pads with linear actuators to make a climbing action, or just put pads on your hands and feet ala Spiderman. It would be really cool to put an HV charger on your belt and a pushbutton inside each pad to discharge it, so you just press your thumb / toe to move that limb.

The hardest part may well be structural integrity of the pads, especially enough to support weight, while being flexible enough to conform to smooth, rough and curved surfaces.

Tim

-- Deep Fryer: A very philosophical monk. Website @

On a sunny day (Fri, 23 May 2008 21:11:08 -0500) it happened "Tim Williams" wrote in :

Yes, looks that way, maybe that is how it moves too, use 2 of those sets with a slight phase shift.

I have seen at TV program where they tried to walk on a ceiling with magnetic shoes. Safety ropes of course, they used a professional acrobat, but even he had big problems putting his legs _up_ to put the foot back again, as then he had to bend his other leg against gravity (and pull up his weight that way).

But hey, give this thing a paint brush, and I have got some work for it :-)

Williams"

It

move

magnetic shoes.

weight

:-)

smooth,

I suppose we might accept the claims with a bit of caution; they are quite remarkable.

There have been surprisingly few proven electrostatic applications over the years. IBM's clutch, Elisha Gray's telephone, Edison's chalk amplifier, and maybe that German loud hailer with the crank handle, and those paper suck down panels... All years and years back.

All the best Ian Macmillan

I had an HP plotter that held the paper that way, back in the early '80s. Could be bad if your wall climber got a bit damp halfway up the wall....

Cheers,

Phil Hobbs

On Sat, 24 May 2008 12:43:39 -0400, Phil Hobbs wrote:

I remember those plotters, had to fix a number of them. They used between 500-1000 VAC, underneath the insulating surface was alternate traces, something like 1/8 in (3-4 mm) between them. There was almost no force until the paper being held was in intimate contact with the surface. Even then the force wasn't that much, nothing even close to the forces claimed on the SRI website (0.8-2 lbs/sq. in). The only time I seen reasoanble forces like that are when you use in excess of

30KV. To hold on a rough surface would require much more than that, since the attraction force drops drastically with distance (roughness). The web site claims an energy requirement of "20 microwatts/Newton weight held", but that's just to hold the thing. Switching that voltage on and off requires a fair amount of energy to charge the "feet". Each foot must have a fair bit of capacitance, and the "lines of force" must go through the substance being walked on. As the feet step on an object, the capacitance increases (charges flow into the resultant capacitor), and the ratio for [capacitance with feet up]/[capacitance with feet down] would determine how well the feet stick. Since the energy varies as the SQUARE of the voltage, and the force varies as the voltage, my guess is that the energy required to turn the foot suction on and off is not a trivial amount. I made capacitors once by having a sandwich of two pieces of aluminum foil, and where the ham should have been, was a sheet of mylar, about a foot square. With a charge of 20KV (mylar is a very good dielectric), it was surprising how much force was required to pull the foil away. I have no doubt that it could be done, but the power supply and switching control would be something that would be pretty difficult to build in your basement! And it must be extremely light weight! If you were ever infested with these things, a bit of salt water would stop them in their tracks......

-Paul