How to Make an Otto Robot Using Raspberry Pi Pico

How to make a Otto Robot using Raspberry Pi Pico

Greetings everyone, and welcome to my Instructables tutorial. Today, I'll guide you through the process of creating an Otto Robot using Raspberry Pi Pico.

Project Overview:

This project is about Otto Robot using Raspberry Pi Pico. The Otto Robot, built using a Raspberry Pi Pico , is a compact and interactive humanoid robot designed for fun and learning. Equipped with servomotors, a PCA9685 PWM driver, and an ultrasonic sensor, it can perform actions like greeting, walking, dancing, and avoiding obstacles. Its stable power supply is ensured by a 9V battery regulated through an LM7805 IC.

This robot showcases the capabilities of the Raspberry Pi Pico, controlling multiple peripherals to create smooth, human-like movements. Its obstacle avoidance feature allows it to navigate autonomously, making it both engaging and functional. Perfect for beginners and hobbyists, this project is an exciting way to explore robotics and programming.

Now, let's get started with our project!

Supplies

WhatsApp Image 2024-12-29 at 08.53.27.jpeg

Electronic Components Required:

(International: amazon.com)

Ultrasonic Sensor: https://tinyurl.com/k9rxwxbh
Raspberry Pi Pico: https://tinyurl.com/4r6trm28
Otto Robot 3D printed Body: https://tinyurl.com/2s4bkzam
SG90 Servo Motor: https://tinyurl.com/3y9x3wsa
PWM/Servo Driver I2C interface PCA9685: https://tinyurl.com/bdfz6bra
LM7805 IC 5V: https://tinyurl.com/3x4nyr5z
9V Battery: https://tinyurl.com/4xa57zk7

(India: quartzcomponents.com)

Ultrasonic Sensor: https://tinyurl.com/mryfn6xn
Raspberry Pi Pico: https://tinyurl.com/4nnub457
SG90 Servo Motor: https://tinyurl.com/e4j2tb8k
PWM/Servo Driver I2C interface PCA9685: https://tinyurl.com/2zrbewh5
LM7805 IC 5V: https://tinyurl.com/bh7uy9r2
9V Battery: https://tinyurl.com/4cjrbs65
9V Battery Snap Connector: https://tinyurl.com/uyevjxzm

Tools

Soldering iron kit
Wire cutter
Glue gun

3D CAD for Otto Robot

Either 3D print the provided CAD design or purchase a pre-made version (available on Amazon).

Downloads

Otto Robo.stl

Assemble the Otto Robot

For this step, you'll need your 3D printed Otto Robot and 4 micro servo motors. Let's put them together:

Feet Assembly:

Insert each micro servo into the feet slots. If they don't fit smoothly, carefully clean the area with a utility knife
IMPORTANT: Test that each servo can rotate a full 90 degrees in both directions
Once movement is verified, secure each servo using a small screw

Body Assembly:

Place 2 micro servos into their designated spots in the robot's body
Secure them with screws
Attach the legs to the servo hubs
Test leg rotation - ensure each can move 90 degrees in both directions from the body
Once aligned, secure the legs using the small screws in the leg holes

Cable Management:

Guide the servo cables through the body slots and leg holes

Pro Tip: Take extra care when routing the cables - proper cable management will ensure smooth movement and prevent wire damage during operation.

Leg & Foot Servo Motor Connection With PCA9685 16 Channel Servo Motor Driver

Servo Motor Driver to Servo Motor Pin Connection.png

Using the connection diagram above, connect each servo motor to its designated channel on the PCA9685 16 Channel Servo Motor Driver:

Left Leg → Channel 0
Right Leg → Channel 1
Left Foot → Channel 2
Right Foot → Channel 3

Program the Raspberry Pi Pico

Before connecting the Raspberry Pi Pico to the circuit, ensure the code is uploaded to it. We will use the Arduino IDE to program the Raspberry Pi Pico, so make sure the Arduino IDE is installed on your device. Follow these steps:

Connect the Raspberry Pi Pico to your device using a USB cable.
Open the Arduino IDE, go to the "File" menu, and click on "Preferences."
In the "Additional Board Manager URLs" field, paste the following URL: https://github.com/earlephilhower/arduino-pico/releases/download/global/package_rp2040_index.json
Click "OK" to save the changes.
Navigate to the "Board Manager," search for "Pico," and install the relevant board as shown in the attached image.
Once the board is installed successfully, select the appropriate board and port from the Arduino IDE.

Then upload this code:

Note: For individual mode codes (walking, dancing, etc.), visit my GitHub repository: https://github.com/ShahbazCoder1/Otto-Robot-using-Raspberry-Pi-Pico-/tree/main

#include <Wire.h>

#include <Adafruit_PWMServoDriver.h>

Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver();

#define SERVO_FREQ 50

#define SERVOMIN 150

#define SERVOMAX 600

// Define servo channels on PCA9685

#define LeftLeg 0

#define RightLeg 1

#define LeftFoot 2

#define RightFoot 3

// Calibration values

int YL = 0; // Left Leg trim

int YR = 0; // Right Leg trim

int RL = 0; // Left Foot trim

int RR = 0; // Right Foot trim

void setup() {

Serial.begin(9600);

// Initialize PCA9685

pwm.begin();

pwm.setPWMFreq(SERVO_FREQ);

}

int angleToPulse(int angle) {

angle = constrain(angle, 0, 180);

return map(angle, 0, 180, SERVOMIN, SERVOMAX);

}

void setServo(uint8_t servoNum, int angle) {

pwm.setPWM(servoNum, 0, angleToPulse(angle));

}

void homePosition() {

setServo(LeftLeg, 90);

setServo(RightLeg, 90);

setServo(LeftFoot, 90);

setServo(RightFoot, 80);

}

void hello() {

setServo(LeftFoot, 60);

for (int i = 0; i < 3; i++) {

setServo(RightLeg, 60);

delay(300);

setServo(RightLeg, 90);

delay(300);

setServo(RightFoot, 60);

delay(300);

setServo(RightFoot, 90);

delay(300);

}

homePosition();

}

void walk() {

// Basic walking sequence

// Step 1: Lift left foot

setServo(LeftFoot, 70);

delay(200);

// Step 2: Move left leg forward

setServo(LeftLeg, 120);

delay(200);

// Step 3: Lower left foot

setServo(LeftFoot, 90);

delay(200);

// Step 4: Lift right foot

setServo(RightFoot, 70);

delay(200);

// Step 5: Move right leg forward

setServo(RightLeg, 120);

delay(200);

// Step 6: Lower right foot

setServo(RightFoot, 90);

delay(200);

homePosition();

}

void dance() {

// Dance move 1: Side-to-side sway

for (int i = 0; i < 3; i++) {

setServo(LeftLeg, 80);

setServo(RightLeg, 100);

delay(300);

setServo(LeftLeg, 100);

setServo(RightLeg, 80);

delay(300);

homePosition();

}

// Foot tapping

for (int i = 0; i < 3; i++) {

setServo(LeftFoot, 60);

delay(200);

setServo(LeftFoot, 90);

delay(200);

setServo(RightFoot, 60);

delay(200);

setServo(RightFoot, 90);

delay(200);

homePosition();

}

// Twisting legs

for (int i = 0; i < 3; i++) {

setServo(LeftLeg, 70);

setServo(RightLeg, 110);

delay(300);

setServo(LeftLeg, 110);

setServo(RightLeg, 70);

delay(300);

homePosition();

}

// Wave legs up and down

for (int i = 0; i < 3; i++) {

setServo(LeftLeg, 60);

setServo(RightLeg, 120);

delay(300);

setServo(LeftFoot, 60);

setServo(RightFoot, 120);

delay(300);

homePosition();

}

// Sideways shuffle

for (int i = 0; i < 3; i++) {

setServo(LeftLeg, 70);

setServo(RightLeg, 110);

setServo(LeftFoot, 80);

setServo(RightFoot, 100);

delay(200);

setServo(LeftLeg, 110);

setServo(RightLeg, 70);

setServo(LeftFoot, 100);

setServo(RightFoot, 80);

delay(200);

homePosition();

}

// Return to home position

homePosition();

}

void loop() {

homePosition();

delay(500);

hello();

delay(5000);

for (int i = 0; i < 5; i++) {

walk();

}

delay(5000);

dance();

delay(5000);

}

Final Circuit

Servo Motor Driver to Pico Pin Connection.png

Using the circuit diagram above, connect the PCA9685 16-Channel Servo Motor Driver to the Raspberry Pi Pico as follows:

GND → GND
SCL → GP2
SDA → GP3
VCC → 3V3

Next, connect the Ultrasonic Sensor to the Raspberry Pi Pico:

GND → GND
TRIG → GP6
ECHO → GP7
VCC → 3V3

Refer to the circuit diagram to create the power source using an LM7805 IC and a 9V battery.

Pro Tip: To simplify the connections and reduce wiring complexity, consider using a PCB board, as we have done, to streamline the circuit assembly. Gerber File: https://drive.google.com/file/d/1AsC0VhEfRiCAE09JpRLL3uXAu8ZMR3mb/view?usp=drive_link

Working Video and Tutorial

How to make an Otto Robot using Raspberry Pi Pico

A demonstration video of this project can be viewed here: Watch Now

Thank you for your interest in this project. If you have any questions or suggestions for future projects, please leave a comment and I will do my best to assist you.

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