Sound-Activated Walking Robot

by littleBits February 7, 2014

This little guy has 2 mounting boards for a body. Just add littleBits and some sturdy legs to get him walking. Control his stride by adjusting the pulse and slide dimmers that connect to his servo-activated legs. Activate the sound and motion triggers and he will happily come over and greet you.

Check out the Mounting Board Tips & Tricks page here.

Bits used: bright led, fork, inverter, motion trigger, power , pulse, servo, slide dimmer, sound trigger, wire

Tags: Motion Sound Fun & Games Fabrication

Videos and Recipes


  1. 1

    Build the circuit: power +wire + motion trigger + sound trigger + wire + bright led + pulse + wire + folk, + slide dimmer + servo (on one branch of the fork), inverter + slide dimmer + servo (on other branch of the fork). Both servos should be set to turn mode. Mask off the motion trigger with tape to desensitize it a bit. See the motion trigger tips & tricks for ideas about how to do this (

  2. 2

    Sandwich two mounting boards together. The sides that connect to littleBits should be facing outwards. We placed some gluedots between two to hold them together.

  3. 3

    Use our template to laser cut front and rear legs of the dog robot. You can use your own design of course though. Bend the rear leg (if you cut it out of acrylic you may need some tool like heat gun). Then attach the servo arms to the legs using gluedots and bind them with some thin wires.

  4. 4

    Make four feet out of erasers or some rubbery material. Put them on the dog’s four bare feet.

  5. 5

    Place the servos in the 3d-printed servo holders (files can be found on Thingiverse:, and Shapeways: ). Attach the servo holders at each end of the mounting board on the bottom side. Make sure that the turning axis of the servo is aligned with the centerline of the mounting board. Because the turning axis is not at the center of the servo motor, the servo holders should be a step off from the center. Before you connect the legs to the servos with small screws, you will want to test and find the best orientation for walking.

  6. 6

    Place the motion and sound triggers in 3d-printed vertical module holders (files can be found at Thingiverse: and at Shapeways: ). Position them at the front of the upper mounting board. Then slide a battery in to the 3d-printed battery holder (file can be found at Thingiverse: and at Shapeways: ) and place it on his tummy.

  7. 7

    Snap the rest of the circuit onto the mounting boards and test walking. Adjust the speed of the pulse to decide how fast he walks. Set the slide dimmers to control how far he stretches out his legs for each step. Make sure that the legs move evenly and secure them to the servos with small screws.

  8. 8

    Make him a coat and use M3 screws to attach it through the screw holes on each corner of mounting board. You can use our coat or your design. We found that the design of the ears and tail are very important for optimal cuteness.

  9. 9

    Everything is ready. Shout out his name, wave your hands and he will come walking to greet you.

Bits used (14)


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Other Materials Used (11)

  • 3d-printed battery holder 1
  • 3d-printed bits vertical mount 1
  • 3d-printed servo holder (horizontal) 1
  • 3d-printed servo holder (vertical) 1
  • acrylic board 1
  • bit shoe 1
  • clear plastic film 1
  • eraser 4
  • M3 screw 4
  • mounting board 2
  • wire 1

Tools (9)

  • 3d-printer
  • gluedots
  • heat gun
  • laser cutter
  • plier
  • scissors
  • screw driver
  • tape
  • utility knife

Other files

  • Tmax 10 months ago

    ...needs more evil

  • AwesomeSadie226 9 months ago


  • about 1 month ago

    Built this for birthday of daughter. A few remarks:
    The servos keep trying to go to one end, this will skew the robot. So you need a mechanical way to limit the servo going to the end or the robot will turn on its back.
    You are better off having the on/off button on the top, contrary to the suggested diagram. This makes it turning it on and off easier.
    Great idea!

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