book

Learn Robotics Programming - Second Edition

by Danny Staple

February 2021

Beginner to intermediate

602 pages

12h 37m

English

Packt Publishing

Read now

Unlock full access

Second EditionWhy subscribe?ContributorsAbout the authorAbout the reviewersPackt is searching for authors like you
Who this book is forWhat this book coversTo get the most out of this bookDownload the example code filesCode in ActionDownload the color imagesConventions usedGet in touchReviews
What does robot mean?Exploring advanced and impressive robotsThe Mars roversDiscovering robots in the homeThe washing machineOther household robotsExploring robots in industryRobot armsWarehouse robotsCompetitive, educational, and hobby robotsSummaryAssessmentFurther reading
Technical requirementsLooking at what's inside a robotExploring types of robot componentsTypes of motors Other types of actuatorsStatus indicators – displays, lights, and soundsTypes of sensorsExploring controllers and I/OI/O pinsControllersChoosing a Raspberry PiPlanning components and code structurePlanning the physical robotSummaryExerciseFurther reading
Technical requirementsExploring the Raspberry Pi's capabilitiesSpeed and powerConnectivity and networkingPicking the Raspberry Pi 3A+Choosing the connectionsPower pinsData busesGeneral IORaspberry Pi HATsWhat is Raspberry Pi OS?Preparing an SD card with Raspberry Pi OSSummaryAssessmentFurther reading
Technical requirementsWhat is a headless system, and why is it useful in a robot?Setting up Wi-Fi on the Raspberry Pi and enabling SSHFinding your Pi on the networkSetting up Bonjour for Microsoft WindowsTesting the setupTroubleshootingUsing PuTTY or SSH to connect to your Raspberry PiConfiguring Raspberry Pi OSRenaming your PiSecuring your Pi (a little bit)Rebooting and reconnectingUpdating the software on your Raspberry PiShutting down your Raspberry PiSummaryAssessmentFurther reading
Technical requirementsUnderstanding how code can be broken or lostSD card data loss and corruptionChanges to the code or configurationStrategy 1 – Keeping the code on a PC and uploading itStrategy 2 – Using Git to go back in timeStrategy 3 – Making SD card backupsWindowsMacLinuxSummaryAssessmentFurther reading
Technical requirementsChoosing a robot chassis kitSizeWheel countWheels and motorsSimplicityCostConclusionChoosing a motor controller boardIntegration levelPin usageSizeSolderingPower inputConnectorsConclusionPowering the robotTest fitting the robotAssembling the baseAttaching the encoder wheelsFitting the motor bracketsFitting plastic motor bracketsFitting metal motor bracketsAdding the castor wheelPutting the wheels onBringing the wires upFitting the Raspberry PiAdding the batteriesSetting up the USB power bankMounting the AA battery holderThe completed robot baseConnecting the motors to the Raspberry PiWiring the Motor HAT inIndependent powerSummaryExercisesFurther reading

Technical requirementsWriting code to test your motorsPreparing librariesTest – finding the Motor HATTest – demonstrating that the motors moveTroubleshootingUnderstanding how the code worksSteering a robotTypes of steeringSteerable wheelsFixed wheelsOther steering systemsSteering the robot we are buildingMaking a Robot object – code for our experiments to talk to the robotWhy make this object?What do we put in the robot object?Writing a script to follow a predetermined pathSummaryExercisesFurther reading
Technical requirementsChoosing between optical and ultrasonic sensorsOptical sensorsUltrasonic sensorsLogic levels and shiftingWhy use two sensors?Attaching and reading an ultrasonic sensorSecuring the sensors to the robotAdding a power switchWiring the distance sensorsInstalling Python libraries to communicate with the sensorReading an ultrasonic distance sensorTroubleshootingAvoiding walls – writing a script to avoid obstaclesAdding the sensors to the robot classMaking the obstacle avoid behaviorsFirst attempt at obstacle avoidanceMore sophisticated object avoidanceSummaryExercisesFurther reading
Technical requirementsWhat is an RGB strip?Comparing light strip technologiesRGB valuesAttaching the light strip to the Raspberry PiAttaching the LED strip to the robotMaking a robot display the code objectMaking an LED interfaceAdding LEDs to the Robot objectTesting one LEDTroubleshootingMaking a rainbow display with the LEDsColour systemsHueSaturationValueConverting HSV to RGBMaking a rainbow on the LEDsUsing the light strip for debugging the avoid behaviorAdding basic LEDs to the avoid behaviorAdding rainbowsSummaryExercisesFurther reading
Technical requirementsWhat are servo motors?Looking inside a servoSending input positions to a servo motorPositioning a servo motor with the Raspberry PiWriting code for turning a servoTroubleshootingControlling DC motors and servo motorsCalibrating your servosAdding a pan and tilt mechanismBuilding the kitAttaching the pan and tilt mechanism to the robotCreating pan and tilt codeMaking the servo objectAdding the servo to the robot classCircling the pan and tilt headRunning itTroubleshootingBuilding a scanning sonarAttaching the sensorInstalling the libraryBehavior codeTroubleshootingSummaryExercisesFurther reading
Technical requirementsMeasuring the distance traveled with encodersWhere machines use encodersTypes of encodersEncoding absolute or relative positionEncoding direction and speedThe encoders we are usingAttaching encoders to the robotPreparing the encodersLifting the Raspberry PiFitting the encoders onto the chassisWiring the encoders to the Raspberry PiDetecting the distance traveled in PythonIntroducing loggingSimple countingTroubleshootingAdding encoders to the Robot objectExtracting the classAdding the device to the Robot objectTurning ticks into millimetersDriving in a straight lineCorrecting veer with a PIDCreating a Python PID controller objectWriting code to go in a straight lineTroubleshooting this behaviorDriving a specific distanceRefactoring unit conversions into the EncoderCounter classSetting the constantsCreating the drive distance behaviorMaking a specific turnWriting the drive_arc functionSummaryExercisesFurther reading
Technical requirementsLearning more about IMUsSuggested IMU modelsSoldering – attaching headers to the IMUMaking a solder jointAttaching the IMU to the robotPhysical placementWiring the IMU to the Raspberry PiReading the temperatureInstalling the softwareTroubleshootingReading the temperature registerCreating the interfaceWhat is VPython?Graphing the temperatureRunning the temperature plotterTroubleshootingSimplifying the VPython command lineReading the gyroscope in PythonUnderstanding the gyroscopeRepresenting coordinate and rotation systemsAdding the gyroscope to the interfacePlotting the gyroscopeReading an accelerometer in PythonUnderstanding the accelerometerAdding the accelerometer to the interfaceDisplaying the accelerometer as a vectorWorking with the magnetometerUnderstanding the magnetometerAdding the magnetometer interfaceDisplaying magnetometer readingsSummaryExercisesFurther reading
Technical requirementsSetting up the Raspberry Pi cameraAttaching the camera to the pan-and-tilt mechanismWiring in the cameraSetting up computer vision softwareSetting up the Pi Camera softwareGetting a picture from the Raspberry PiInstalling OpenCV and support librariesBuilding a Raspberry Pi camera stream appDesigning the OpenCV camera serverWriting the CameraStream objectWriting the image server main appBuilding a templateRunning the serverTroubleshootingRunning background tasks when streamingWriting a web app coreMaking a behavior controllableMaking the control templateRunning the controllable image serverFollowing colored objects with PythonTurning a picture into informationEnhancing the PID controllerWriting the behavior componentsWriting the control templateWriting the behavior codeRunning the behaviorTroubleshootingTracking faces with PythonFinding objects in an imageConverting to integral imagesScanning for basic featuresPlanning our behaviorWriting face-tracking codeRunning the face-tracking behaviorTroubleshootingSummaryExercisesFurther reading
Technical requirementsIntroduction to line followingWhat is line following?Usage in industryTypes of line followingMaking a line-follower test trackGetting the test track materials in placeMaking a lineLine-following computer vision pipelineCamera line-tracking algorithmsThe pipelineTrying computer vision with test imagesWhy use test images?Capturing test imagesWriting Python to find the edges of the lineLocating the line from the edgesTrying test pictures without a clear lineLine following with the PID algorithmCreating the behavior flow diagramAdding time to our PID controllerWriting the initial behaviorTuning the PIDTroubleshootingFinding a line againSummaryExercisesFurther reading
Technical requirementsIntroducing Mycroft – understanding voice agent terminologySpeech to textWake wordsUtterancesIntentDialogVocabularySkillsLimitations of listening for speech on a robotAdding sound input and output to the Raspberry PiPhysical installationInstalling a voice agent on a Raspberry PiInstalling the ReSpeaker softwareTroubleshootingGetting Mycroft to talk to the sound cardStarting to use MycroftThe Mycroft clientTalking to MycroftTroubleshootingProgramming a Flask APIOverview of Mycroft controlling the robotStarting a behavior remotelyManaging robot modesProgramming the Flask control API serverTroubleshootingProgramming a voice agent with Mycroft on the Raspberry PiBuilding the intentThe settings fileThe requirements fileCreating the vocabulary filesDialog filesCurrent skill folderTroubleshootingAdding another intentVocabulary and dialogAdding the codeRunning with the new intentSummaryExercisesFurther reading
Technical requirementsProgramming a virtual robotModeling the robot in VPythonTroubleshootingDetecting rotation with the gyroscopeCalibrating the gyroscopeRotating the virtual robot with the gyroscopeTroubleshootingDetecting pitch and roll with the accelerometerGetting pitch and roll from the accelerometer vectorTroubleshootingSmoothing the accelerometerDelta timeFusing accelerometer and gyroscope dataTroubleshootingDetecting a heading with the magnetometerCalibrating the magnetometerTroubleshootingTesting the calibration valuesWhat to do if the circles aren't togetherGetting a rough heading from the magnetometerCombining sensors for orientationFixing the 180-degree problemDriving a robot from IMU dataSummaryExercisesFurther reading
Technical requirementsWhen speech control won't work – why we need to driveMenu modes – choosing your robot's behaviorManaging robot modesTroubleshootingThe web serviceThe templateRunning itTroubleshootingChoosing a controller — how we are going to drive the robot, and whyDesign and overviewPreparing the Raspberry Pi for remote driving—get the basic driving system goingEnhancing the image app coreWriting the manual drive behaviorThe template (web page)The style sheetCreating the code for the slidersRunning thisTroubleshootingMaking the robot fully phone-operableMaking menu modes compatible with Flask behaviorsLoading video servicesStyling the menuMaking the menu template into buttonsMaking the menu start when the Pi startsAdding lights to the menu serverUsing systemd to automatically start the robotTroubleshootingSummaryExercisesFurther reading
Online robot building communities – forums and social mediaYouTube channels to get to knowTechnical questions – where to get helpMeeting robot builders – competitions, makerspaces, and meetupsMakerspacesMaker Faires, Raspberry Jams, and DojosCompetitionsSuggestions for further skills – 3D printing, soldering, PCB, and CNCDesign skills2D design for illustration and diagrams3D CADSkills for shaping and buildingMachine skills and toolsHand skills and toolsElectronics skillsElectronics principlesTaking soldering furtherCustom circuitsFinding more information on computer visionBooksOnline coursesSocial mediaExtending to machine learningRobot Operating SystemSummaryFurther reading
Technical requirementsVisualizing your next robotMaking a block diagramChoosing the partsThe test-fit diagramBuying partsAssembling your robotPlanning the code for the robotSystem layersData-flow diagramsFormal diagramsProgramming the robotLetting the world knowSummary
Leave a review - let other readers know what you think

Content preview from Learn Robotics Programming - Second Edition

Chapter 10: Using Python to Control Servo Motors

Servo motors can make precise and repeatable motions. Motion such as this is vital for moving sensors, controlling robot legs or arms, and moving them to a known position. Its uses are so engineers can predict robot behavior, so a robot can repeat things in automation, or so code can move limbs to accurately respond to what their sensors are instructing them. Raspberry Pi or add-on boards can control them. In this chapter, we will use these motors to build a pan and tilt mechanism—a head to position a sensor.

In this chapter, we will cover the following topics: