Ricardo

1. Introduction

Ricardo is an open-source robot which aim is to make replicating it an easy and fun process so that anyone who is interested in robotics can get into the field and progress. Ricardo is fully 3D printable and uses some 3D models from thingiverse. The electronics are all readily available and relatively cheap such as the Raspberry Pi and other Arduino modules which make upgrading and repairing him an easy process. This document contains a guide in the following sections on all of the parts and how they are connected so that you can easily start making your own Ricardo. The README file shall be updated consistently with new changes and it is the documentation for the entire project.

2. Project structure

1. Files

The repository consists of several python scripts which will need to be runned from the Raspberry Pi for all of this to work. You need this repository cloned on your Raspberry Pi. The scripts can be divided into two categories: user driven and AI driven. In the user driven scripts (ex: robot_control.py) the user inputs commands in order to control the robot. In the AI driven scripts the AI controls the robot either entirely or lets the user also have some control.

2. Physical architecture

Ricardo's "brain" is a Raspberry Pi. It controls all of the parts. The Raspberry Pi either connects to a WiFi router or it just becomes a hotspot and devices can connect to it in order to envoke the scripts via ssh or vnc. The robot has four motors that drive the two tank tracks. These motors are driven by the L298N motor driver which gets inputs from the Raspberry Pi directly. For vision the robot uses the Pi Camera module mounted on a camera rotating system driven by two servo motors. The robot also has accessories such as front lights and a horn (more accessories can be added) The Raspberry Pi and the accessories (including camera rotation servos) are powered on a 20000 mAh power bank. Everything on the robot is powered with the 5V power bank except the L298N motor controller which uses 2x18650 batteries in serial (7.4V) which works well for the motors.

3. Functionalities and logic

1. AI driven

• Robot follows person by tracking their face (face_tracker_picam.py)
  • If tracked face enters left region the robot turns left
  • If tracked face enters right region the robot turns right
  • If the tracked face enters the left and right turning trigger area then it continues operating normally and does not rotate
  • Moving forward and backward are done by calculating the area of the tracked face. If the face area is larger than a ceratin threshold, then the robot drives backwards from the person. if the face area is smaller than a certain threshold, then the robot drives towards the user

2. User driven

• Remote control of the robot (robot_control.py)
  • Live video preview
  • Ability to capture video
  • Ability to take pictures
  • Manual camera rotation
  • Manual motor control
  • Ability to use front LED lights
  • Ability to use horn

4. Parts

1. Electronic connections with Raspberry Pi GPIO pins