Robotics at Home with Raspberry Pi Pico: Build autonomous robots with the versatile low-cost Raspberry Pi Pico controller and Python

Cover
Copyright
Contributors
Table of Contents
Preface
Part 1: The Basics – Preparing for Robotics with Raspberry Pi Pico
Chapter 1: Planning a Robot with Raspberry Pi Pico
	Technical requirements
	What is Raspberry Pi Pico, and why is it suitable for robotics?
		A microcontroller that runs Python
		Raspberry Pi Pico’s interfaces for sensors and devices
	What is CircuitPython?
	Planning a Raspberry Pi Pico robot
		An overview of robot planning
		A note on trade-offs
		Choosing a robot chassis
		Choosing the power systems
		Pin usage
	Test fitting a Raspberry Pi Pico robot
		Creating your first test-fit part
		Motors
		Power systems
		Creating a rough chassis
		Arranging the test-fit parts
	A recommended shopping list for robot basics
		Robot parts and where to find them
		The robot workshop and makerspaces
	Summary
	Exercises
	Further reading
Chapter 2: Preparing Raspberry Pi Pico
	Technical requirements
	Getting CircuitPython onto Raspberry Pi Pico
	Preparing the CircuitPython library for Pico
	Coding on Pico – first steps
		Downloading the Mu editor
		Lighting the Pico LED with CircuitPython
		Blinking the LED with code
	Soldering headers to Raspberry Pi Pico
	Summary
	Exercises
	Further reading
Chapter 3: Designing a Robot Chassis in FreeCAD
	Technical requirements
	Introducing FreeCAD
		The FreeCAD screen
		Selecting workbenches
		FreeCAD settings
	Making robot chassis sketches in FreeCAD
		Preparing the document
		Sketching the chassis outline
		Creating the upper parts main sketch
		Sketching the motor holes
	Designing the castor placement
	Modeling chassis parts from sketches
		Modeling the chassis plate
		Modeling the other parts
		Troubleshooting the model
		Modeling the castor in 3D
	Making FreeCAD technical drawings
		Setting up the page
		Adding parts to the drawing
		Preparing the drawing for print
	Summary
	Exercises
	Further reading
Chapter 4: Building a Robot around Pico
	Technical requirements
	Cutting styrene parts
		Transferring CAD measurements to a plastic sheet
		Cutting the plastic sheet
		Finishing and sanding the chassis plate
	Assembling a robot chassis
		Attaching the caster and battery box
		Attaching the motors and wheels
	Wiring a Raspberry Pi Pico robot
		Wiring Pico and the motor controller into the breadboard
		Adding the batteries
		Wiring in the motors and encoders
		Powering the robot up
	Summary
	Exercises
	Further reading
Chapter 5: Driving Motors with Raspberry Pi Pico
	Technical requirements
	Driving forward and back
		Testing each motor with CircuitPython
		Driving wheels in a straight line
	Steering with two motors
	An introduction to pulse width modulation speed control
		Driving fast and slow
		Turning while moving
	Driving along a planned path
		Putting line and turn moves together
		The flaw with driving this way
	Summary
	Exercises
	Further reading
Part 2: Interfacing Raspberry Pi Pico with Simple Sensors and Outputs
Chapter 6: Measuring Movement with Encoders on Raspberry Pi Pico
	Technical requirements
	About encoders and odometry
		Absolute and relative sensing
		Types of encoders
		Encoder pulse data
	Wiring in encoders on a Raspberry Pi Pico robot
		Examining the motors
		Examining the wiring
	Programming Raspberry Pi Pico PIO
		Introduction to PIO programming
		Introducing PIOASM
		Detecting input with PIO
		PIO instructions and registers
		Making a counter with PIO
	Measuring encoder count for movement
		Making a simple PIO change detection loop
		Making a bidirectional counter with PIO
		Making reusable encoder code
		Measure counts for a known time
	Summary
	Exercises
	Further reading
Chapter 7: Planning and Shopping for More Devices
	Technical requirements
	Introducing sensors
		Analog sensor types
		Timed pulses
		Data bus sensors
		The robot block diagram
	Choosing device types
		Distance sensors
		Inertial measurement unit
		Bluetooth devices
		Device pin usage summary
	Planning what to add and where
		Bluetooth and IMU mounting plan
		Distance sensor mounting plan
	Shopping list – parts and where to find them
	Preparing the robot
		Designing the shelf
		Cutting the shelf
		Designing the front sensor brackets
		Cutting the sensor brackets
		Preparing the chassis plate
		Assembling the robot
	Summary
	Exercises
	Further reading
Chapter 8: Sensing Distances to Detect Objects with Pico
	Technical requirements
	How distance sensing works
	Soldering headers and attaching them to the robot
		Soldering headers
		Mounting the sensors
	Introduction to I2C communication
	Communicating with a single distance sensor
		Wiring the distance sensors
		VL53LX theory of operation
		Reading a single distance sensor in CircuitPython
		Troubleshooting
	Connecting two distance sensors
		Troubleshooting
	Building a wall avoider with Raspberry Pi Pico
		Preparing the robot library
		Wall-avoiding theory of operation
		Distance sensor wall avoider code
	Troubleshooting
	Summary
	Exercises
	Additional reading
Chapter 9: Teleoperating a Raspberry Pi Pico Robot with Bluetooth LE
	Technical requirements
	Wireless robot connection options
	Connecting Bluetooth LE to Raspberry Pi Pico
		Attaching the Bluetooth module to the robot
		Wiring the Bluetooth breakout to Raspberry Pi Pico
		Connecting to the Bluefruit LE device with UART
		Connecting a smartphone
		Troubleshooting the Bluefruit module
	Getting sensor data over Bluetooth LE on Raspberry Pi Pico
		Graphing the data
	Controlling the robot with Bluetooth LE
		Printing what we got
		Button control mode
		Decoding button control packets to drive the robot
		Troubleshooting
	Summary
	Exercises
	Further reading
Part 3: Adding More Robotic Behaviors to Raspberry Pi Pico
Chapter 10: Using the PID Algorithm to Follow Walls
	Technical requirements
	Introducing the PID algorithm
		Control and feedback
		Bang-bang control
		Distance sensing with proportional control
		Troubleshooting
		Using the integral to handle small distances
		Dealing with oscillations using the derivative
	Using PID to follow a wall
		Changing the sensor’s placement
		Wall-following code
		Troubleshooting
	PID tuning – using graphs to tune the PID
		Controlling motor speed
		The proportional component
		Adjusting the derivative gain
		Tuning the integral
		Closing notes on tuning
	Summary
	Exercises
	Further reading
Chapter 11: Controlling Motion with Encoders on Raspberry Pi Pico
	Technical requirements
	Converting an encoder count into a speed
		Loose bolts and nuts
		Robot wheel geometry
		Encoder geometry
		Measuring the speed of each wheel
		Fixing the encoder glitches
	Using PID to maintain speed and a straight line
		The speed control system
		Speed control code
		Speed controller PID tuning
	Driving a known distance
		Theory of operation
		Code to control distance and speed
	Summary
	Exercises
	Further reading
Chapter 12: Detecting Orientation with an IMU on Raspberry Pi Pico
	Technical requirements
	What is an IMU and how to choose one
		Components of an IMU
		Choosing an IMU module
	Connecting the IMU to the robot
		Preparing the BNO055
		Attaching the BNO055
		Wiring the BNO055 to Raspberry Pi Pico
		Setting up the software and connecting
		Troubleshooting
	Calibrating and getting readings
		Calibration code
		The calibration process
	Always face North behavior
		CircuitPython code for the face North behavior
		Troubleshooting
	Making a known turn behavior
	Summary
	Exercises
	Further reading
Chapter 13: Determining Position Using Monte Carlo Localization
	Technical requirements
	Creating a training area for our robot
		What we will make
		How we will make the arena
		Tips for cutting
	Modeling the space
		Representing the arena and robot position as numbers
		Serving the arena from the robot
		The Bleak library
		Creating a Bluetooth LE wrapper library
		Showing the robot’s data on the computer screen
	Using sensors to track relative pose
		Setting up poses
		Displaying poses
		Moving with collision avoidance
		Moving poses with the encoders
		Pose movement probabilities
	Monte Carlo localization
		Generating pose weights from a position
		Resampling the poses
		Incorporating distance sensors
		Tuning and improving the Monte Carlo model
	Summary
	Exercises
	Further reading
Chapter 14: Continuing Your Journey – Your Next Robot
	Technical requirements
	A summary of what you have learned in this book
		Basic robotics with Raspberry Pi Pico
		Extending a Raspberry Pi Pico robot with sensors
		Writing CircuitPython behavior code for Raspberry Pi Pico
	Planning to extend this robot
		Sensors you could add
		Interacting with the robot
		Chassis and form enhancements
		Electronics enhancements
		Outputs you could add
		Extending the code and behaviors
	Planning your next robot
		Form, shape, and chassis
		Electronics and sensors
		Code and behavior
	Further suggested areas to learn about
		Electronics
		Design and manufacturing
		Robotic competitions and communities
		Robotics systems and code
	Summary
	Exercises
	Further reading
Index
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