The Sandwalker standing on firm wet sand at low tide, its fifteen brown feet planted in a row, pastel links catching low sun

Sandwalker

Fifteen legs and one red handle. Turn it, and the whole frame walks almost level.

It starts at the red handle.

No motor, no battery, no switch. The small red handle at one end of the frame is the whole drive, and one turn of it is one full step of every leg.

One shaft, eight cranks.

The handle turns a single crankshaft that runs the length of the frame. Its 8 cranks stand 45° apart, so the legs they drive never move in step.

Each crank pulls a pair.

A crank drives one leg on each side through two links: a lilac one up to the cream triangle, a pale one down to the brown foot. A fixed rod on each side holds the pivots.

Six links draw one footstep.

Every leg is Theo Jansen's linkage at 2.5× his proportions. The crank goes round, and the foot traces this line: a long flat push along the ground, then a 1.6 in lift on the way back.

Fifteen legs, never all at once.

8 legs on one side, 7 on the other. At every moment of a turn, 5 to 7 of the feet are on the ground.

So it walks almost level.

With feet always planted, the frame rises and falls less than 0.02 in as it goes. One turn of the handle carries it about 13.0 in.

One turn, one footstep.

This is the path a single foot follows while the handle goes round once, drawn from the leg's own link lengths. The flat bottom is why the Sandwalker glides instead of bobbing: for most of the turn the foot slides straight back along the ground, and the frame above it never has to rise.

The foot path of one leg: a flat stroke along the ground, then a raised arch back walks this way foot on the ground lifted 1.6 in, carried back
Step per turn
13.0 in
Foot lift
1.6 in
Feet down
5 to 7 of 15
Frame bob
under 0.02 in

Up close

The Sandwalker on a sunlit oak desk next to a keyboard and a coffee mug, standing several mugs tall
On my desk next to the keyboard. Beside the coffee mug you can see how big it really is.
Close view of the red handle and crank at the end of the frame, with lilac links fanning out from the crankshaft
The red handle sits at the far end, on the same shaft as all eight cranks.
The other side of the walker: green and pink side links, black rivets at each joint, brown feet at different heights
Every joint is riveted, and each foot sits at a different point in its step.
The Sandwalker seen end on, standing on a wooden sideboard beside a potted plant and two books
Between walks it stands on the sideboard, end on, and reads like a small sculpture.
A hand holding the grey end frame of the Sandwalker on a wooden living-room floor beside a rug
On the living-room floor. I carry it by the grey end frame.

Sandwalker

A hand-cranked walking machine on fifteen Jansen legs.

Size
20.8 × 16.9 × 12.8 in
Weight
2.1 lb
Legs
15 Jansen linkages, 8 on one side and 7 on the other
Drive
Red hand crank on a 8-crank shaft; no motor, no batteries
Step
About 13.0 in per turn of the handle
Ride
5 to 7 feet always down; the frame bobs under 0.02 in
Material
PLA, riveted at every joint

Good to know

Does it need batteries?
No. There is no motor and nothing to charge. You turn the red handle by hand, and the crankshaft carries that turn to all fifteen legs.
How does it walk so smoothly?
Each leg is a Jansen linkage, the same six-link leg Theo Jansen uses on his beach walkers. Its foot moves along a flat line on the ground and lifts 1.6 in on the way back, and with 5 or more feet always down the frame stays within 0.02 in of level.
How far does one turn take it?
About 13.0 in across a flat floor or firm sand, one full step of every leg.
What is it made of?
PLA, with a rivet through every joint. The legs, links and crankshaft are each their own colour, so you can follow the drive by eye.
How big is it?
20.8 × 16.9 × 12.8 in, long by wide by tall, and it weighs 2.1 lb. Give it a clear stretch of floor or a firm beach.