This robot is based on several "walker-robots" found on the web, and it`s one of many versions of a 2-servo walking robot. Our idea behind this robot was to try to build a cheap as possible robot kit for children in schools, youth clubs, and so on. The body of the robot is foam board (it might be several product names on this boards, in Norway Kapaplate is one of the most common ones). It`s light, cheap and most important of all; it`s easy to cut.

We did use a Atmel Xplained mini for the first robots. The Xplained mini has the same footprint as an Arduino Uno. We have also scaled down this robot, and used Arduino Nano.

Step 1: Step 1: the Body

You will need about an A5 sheet (about 10x20 cm) (Inches? Well, that should be about 4x8" I think)

Cut out the shapes. You need one "base plate" and two "side plates".

Measure the size of your servos. You might need to change the size for the servos in the base plate.

The baseplate will have a slightly upward angel at the front, so you need to cut almost through the baseplate. (If you are unlucky and cut all the way through, it`s fixable. Just use more glue when you put it together :))

Glue all the pieces together.

Step 2: Step 2: the Servos

We are using two 9g servos. So if you are using some other sizes, you might need to resize the holes.

Cut away the servo plug.

Place the servo in the holes on the body, with the "Servo shaft" facing the edge. Glue it on to the body.

Get some header pins. You need 3x2 pins

Pair one: Solder the pwm-wire (yellow or white) from each servo to each of the header pins. (One wire to one pin!)

Pair two: Solder both of the black (ground) wires to one of the pins, and solder the red (+) to one of the other pins.

Pair three: Solder black and red wire from 9V snap-on connector to pins

Step 3: Step 3: Bending the Legs

This is the hard part...

Cut two pieces of 2mm steel wire in lengths of about 40-50 cm each.

Bend them in half, and make a sharp bend. You might need to use a plier to get the bend sharp enough.

Bend the wires as seen in the pictures. There is several possibilites, and the walking characteristics will depend on how the legs are shaped. Wide stance vs narrow, lenght of legs, angels etc.

Mount servo horns on the servos, and be sure that they are centered. (You could fine tune this in the arduino code later)

Glue the legs to the servo horns.

Step 4: Step 4: Wiring It Up and Flashing the Code

Attach the header pins to the following Arduino pins:

Pair one: PWM-pins. PWM-wire from front servo to A0 and back servo to A1

Pair two: + and gnd from servos. Red to 5V and black to gnd

Pair three: Battery connector. Red to vin and black to gnd

----- the code ----

#include

Servo frontServo; Servo backServo;

int frontPos = 90; // change this number to center the front legs
int backPos = 90; // change this number to center the back legs

// Speed
int rate = 200; // this will change the walking speed, higher number = slower, lower = faster

void setup() {
frontServo.attach(A0);
backServo.attach(A1);

}

void loop() {

frontServo.write(frontPos + 20);
delay(rate);
backServo.write(backPos - 20);
delay(rate);
frontServo.write(frontPos - 20);
delay(rate);
backServo.write(backPos + 20);
delay(rate);

}