Introduction: Walking Robot With 3 Servo

This is a simple biped robot can walk. Made of Arduino, three servos
and simple mechanism.Command to the robot, it can move forward, backward, even rotate or turn.

One servo is to move the center of gravity. Another two are to twist both feet. Put weight to right and twist right foot, weight to left and twist left foot and loop it.

Easy way to move center of gravity is using servo to swing something heavy weight. Batteries are suitable for it, because most of this robot weight is 4 x AA Batteries.

This robot is moving on delicate balance, so need flat and non-slippy floor, but even then sudden move cause unintended movement. I tried to devise the program to make it move smoothly.

Start servo slowly and accelerate, decelerate, and stop. Swinging arm did not move smoothly no matter how I did it, I think it is because of the lack of servo power.


  • Arduino Nano

Any board may OK, if work Arduino code.

  • 3 x Servo

I used SG90 micro servo, I recommend more bit powerful one for swinging servo.

  • 4 x AA NiMh batteries and case.

To connect direct Arduino 5V port, Alkaline battery is too high voltage.

  • Material for robot frame, swinging arm and foot

I used 2mm x 10mm x 375mm aluminum bar for frame. And 2mm x 10mm x 70mm plastic bar for swinging arm. 2 x plastic bottle cap for feet. If you can get more thin bar like 1mm x 15mm, you can make and adjust frame more easy.

  • Soldering wire, Double-sided tape, duct tape, Mini Screw or so

Step 1:

Make robot frame with aluminum bar. Make swinging mechanism. To swing heavy batteries, fix it tight with screw.

Step 2:

  • Fix servo to frame and tie the cables.
  • Wiring servo and Arduino. No.9 to R-foot No.10 to L-foot No.11 to swing, GND and 5V.

Step 3:

Program to Arduino. Be care while connecting to PC, disconnect batteries.

Step 4:

Make the robot body. It can be any shape, but it needs to be lightweight. If you put on the body, you can see which is the front.

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