🕷️ Klann Walking Spider: step-by-step build

A robot that WALKS instead of rolling — beams and pins turn a spinning crank into steps.

Wheels are great on smooth floors, but spiders, dogs and people walk. Can a machine walk with just one motor? Yes — with a walking linkage! Each leg is two beams and a tiny crank joined by smooth pins. As the crank goes round, the foot draws a shape like a letter D: a flat line along the floor (pushing the body forward) and a hop back through the air. Engineer Joe Klann and artist Theo Jansen built whole walking machines like this. Our spider has four legs; the diagonal pairs take turns, so it never falls over.

  • Level 4 of 5 (tricky)
  • About 60 minutes
  • 17 steps, 45 parts
  • Powered by: Motor
  • Series: Mechanical Wonders

What you will learn

  • Linkages: Beams joined by pins change one motion into another.
  • Crank & Slider: A turning crank pushes a rod back and forth.
  • Drive Train: The chain of parts that carries power from the motor to the wheels.
  • Mounting a Motor: A motor must be pinned tight, or it spins itself instead of your wheels.
  • Plugging In: Power Functions: Battery box → (switch or receiver) → motor. Plugs stack like bricks.
  • Electric Circuits: Electricity flows from the battery, through the motor, and back.

Build these first

  • 🔋 Motor Buggy: Your first car that drives by itself — with a forwards/backwards switch and headlights! (level 3 of 5, about 30 minutes, 20 steps)
  • 🦾 XL Power Crane: The strongest motor plus a worm gear: 24 times slower and super strong. (level 4 of 5, about 35 minutes, 27 steps)

Parts you need

  • 2 × Open frame 5×11
  • 1 × Axle 6
  • 5 × Bush
  • 1 × Medium gear (24 teeth)
  • 2 × Axle 5
  • 1 × Giant gear (40 teeth)
  • 2 × Thin beam 2
  • 4 × Beam 11
  • 6 × Grey pin (smooth)
  • 4 × Beam 9
  • 2 × Axle 4
  • 4 × Blue long pin
  • 5 × Half bush
  • 1 × Tiny gear (8 teeth)
  • 2 × Black pin (grippy)
  • 1 × L motor
  • 1 × AA battery box
  • 1 × LED lights

Steps

  1. Stand a 5×11 frame up on its long side. This is the left wall of the body.
  2. Push a 6-long crankshaft through the middle of the bottom row with a bush, the 24-tooth gear and a bush.
  3. Push a 5-long upper axle through the middle of the top row with a bush, the giant 40-tooth gear and a bush.
  4. Slide the right wall onto both axles, and push the tiny yellow right crank onto the right end of the crankshaft, pointing forwards, so the wall cannot slide off.
  5. Push the other yellow crank onto the left end of the crankshaft, pointing backwards — the OTHER way to the right one.
  6. Left legs: push a smooth grey pin through the 9th hole of an 11-hole leg and press the end hole of a 9-hole rocker onto it.
  7. Make the mirror-image back leg: push a 4-long axle through the first holes of both legs, and join the back leg to its rocker with a blue long pin.
  8. Slide a half bush onto each end of the 4-long axle, so it cannot slide out of the legs.
  9. Slide the legs' 4-long axle into the crank's outer hole, and push a smooth grey pin through the top hole of each rocker into the wall's bottom row (holes 3 and 9).
  10. Right legs: build the front leg again…
  11. …and the mirror-image back leg on a 4-long axle.
  12. A half bush on each end of the axle.
  13. Slide the right legs' axle into the right crank and pin both rockers to the right wall with smooth grey pins.
  14. Hold a half bush, the 8-tooth gear (meshing the 40) and a bush in a row inside the body, and push a 5-long axle in through the 9th hole of the right wall's top row and through all three. The bushes keep the little gear from sliding.
  15. Push 2 black pins into the top-row holes on both sides of that axle, then press the L motor's front face onto the pins and the axle.
  16. Push blue long pins into the top corner holes of the left wall, pointing outwards, and hang the AA battery box on them by its end ears. Plug the motor onto the box.
  17. Clip the LED lights on the front as glowing spider eyes and plug them onto the box too.

Play time

Switch on and let the spider walk across the floor. Race it against a wheeled car! Flip the switch on the box — can it walk backwards? Put a book in its way: can it climb over a pencil?

Real-world inspiration

DIY Walkers LEGO walker instructions — https://www.diywalkers.com/build-instructions.html ; Klann linkage — https://en.wikipedia.org/wiki/Klann_linkage ; Strandbeest optimiser — https://www.diywalkers.com/strandbeest.html