This mechanical bull was created as a weekend hobby. The creation process was simple and did not last more than two hours. The materials I already had at home. For those who wish to make an equal, will be a good opportunity to recycle materials and learn how to use the joystick shield with Arduino. Hope you enjoy.

Step 1: Materials:

- A volunteer (doll)
- Pieces of cardboard
- An empty soft drink
- Two servomotors
- A Arduino Uno
- A Joystic Shield
- Arms for the servants
- Three screws
- nuts and a washers
- Hot glue, scissors, knife, etc. ...

Step 2: Creating the Model

I used a can of soda as a model for the doll bull riding. After that, I drew on the cardboard, cut out the template and glued using hot glue.

Step 3: Joining the Servomotors

The servo motors are fixed on each other as shown, using a piece of cardboard to position them correctly and hot glue.

Step 4: Attaching the Mount

Joining small pieces of cardboard with a hole in the center, was made a bracket to hold the mount in servants.

Step 5: Joining the Servants and the Mount

I used a bolt, a nut and washer to secure the mount in servants, according to the figure.
Also used a piece to make the linking of movement between the servo arm and mount. This part should be a little slack for not hang with the movements.

Step 6: Fixing on a Base

The base was made with a simple cardboard cutout. I made the design of servo arm that controls the base, cut out and pasted it on cardboard with hot glue.
I used a part of the soda can as a handle to hold the puppets up on it.

Step 7: Assembling and Programming the Controller

Software:
#include <Servo.h> // incluindo a biblioteca dos servos

Servo SRx;

Servo SRy;

const int VRx = A0;

const int VRy = A1;

int sensorVRx = 0;

int sensorVRy = 0;

int outputVRx = 0;

int outputVRy = 0;

long tempo_anterior= 0;

long intervalo= 100; //milisegundos

unsigned long tempo_atual;

void setup()

{
Serial.begin(9600);

SRx.attach(9);

SRy.attach(10);

}

void loop()

{

tempo_atual = millis();// o tempo atual é igual ao tempo de funcionamento do uC

sensorVRx   = analogRead(VRx);

sensorVRy   = analogRead(VRy);

outputVRx   = map(sensorVRx, 0, 1023, 0, 180);

outputVRy   = map(sensorVRy, 0, 1023, 0, 180);

if(tempo_atual - tempo_anterior > intervalo)// se o tempo atual menos o tempo anterior for maior que o intervalo com que eu quero fazer minha acao

    {

      tempo_anterior = tempo_atual;//tempo anterior recebe o tempo atual

      Serial.print(outputVRx);

      Serial.print(",");

      Serial.print(outputVRy);

      Serial.print(",");

      Serial.println("");

    }

SRx.write(outputVRx);

SRy.write(outputVRy);

delay(2);

}

Running:

Introduction: Mechanical Bull for Dolls