{ "schema": "tinyskiff.lessonPacket.v0", "lessonCode": "TSK-DAY23-SERVOSWEEP", "course": "TinySkiff ESP32-S3 Lab", "day": 23, "title": "Servo sweep: move to positions", "status": "published", "learnerProfile": "adult beginner; curious and capable; no electronics assumed", "estimatedTimeMinutes": 20, "mission": "Wire a servo's three leads to the board, upload the Arduino sketch, and watch the horn sweep smoothly from 0° to 180° and back — your first part that moves to an exact position on command.", "mainPath": "Arduino/C++", "optionalSidePath": "MicroPython", "sourceMetadata": { "officialPdf": "source/Freenove_Super_Starter_Kit_for_ESP32_S3-main/C/C_Tutorial.pdf", "chapter": "Chapter 17 Servo", "page": 154, "arduinoSketch": "source/Freenove_Super_Starter_Kit_for_ESP32_S3-main/C/Sketches/Sketch_17.1_Servo_Sweep/Sketch_17.1_Servo_Sweep.ino", "micropythonFile": "source/Freenove_Super_Starter_Kit_for_ESP32_S3-main/Python/Python_Codes/16.1_Servo_Sweep/Servo_Sweep.py", "imageAsset": "docs/course/assets/day-23/circuit-page-154.png", "imageAlt": "Official Freenove circuit for the servo sweep: a servo's orange signal wire on GPIO 21, its red power wire on 5V, and its brown ground wire on GND, shown as both a schematic and a breadboard photo.", "licenseNote": "Based on Freenove official material released under CC BY-NC-SA 3.0; preserve attribution and non-affiliation language.\n" }, "parts": [ { "name": "ESP32-S3 board", "imageAsset": "docs/course/assets/shared/item-esp32-s3-board.jpg", "explanation": "A development board is a friendly package around a tiny computer chip. The ESP32-S3 runs your uploaded sketch, controls pins, reads sensors, and can also use USB, Wi-Fi, and Bluetooth. In this lesson, it sends the ping signal and measures the echo time." }, { "name": "GPIO extension board", "imageAsset": "docs/course/assets/shared/item-gpio-extension-board.png", "explanation": "GPIO means general-purpose input/output. These pins are connection points your code can use. The extension board makes them easier to see, reach, and wire without cramming everything onto the ESP32-S3 itself." }, { "name": "Servo", "imageAsset": "docs/course/assets/shared/item-servo.png", "explanation": "A servo packs a DC motor, reduction gears, a position sensor, and a control circuit into one case. Send it a timing signal and it rotates its horn to the angle you asked for and holds there — 0 to 180 degrees. Three wires: orange signal, red power, brown ground." }, { "name": "3 jumper wires (M/M)", "imageAsset": "docs/course/assets/shared/item-jumper-wire.png", "explanation": "Jumper wires make temporary connections without soldering. Female-to-male wires have a socket on one end and a pin on the other, useful when a sensor module and board use different connector styles." }, { "name": "Arduino IDE", "imageAsset": "docs/course/assets/shared/item-arduino-ide.png", "explanation": "Arduino IDE is the desktop app that opens the sketch, compiles it, uploads it to the ESP32-S3, and shows messages from the board in Serial Monitor." } ], "wiring": [ { "partPin": "Servo signal (orange)", "connectTo": "GPIO 21", "reason": "Carries the timed pulse that names the angle." }, { "partPin": "Servo power (red)", "connectTo": "5V", "reason": "Feeds the servo's motor with enough current to move." }, { "partPin": "Servo ground (brown)", "connectTo": "GND", "reason": "Gives board and servo the same zero point." } ], "coachInstructions": [ "Guide one physical connection at a time and wait for learner confirmation before proceeding.", "Colour is the map — orange signal to GPIO 21, red to 5V, brown to GND; check that order before anything else.", "If the horn twitches or judders, confirm the red wire sits on the 5V pin with its own jumper — a GPIO cannot supply a servo's current.", "If it sweeps once then jams at an end, the horn is hitting something — have the learner refit it on the shaft.", "If the board resets mid-sweep, the USB supply is weak — unplug other loads before changing any code.", "Keep the Arduino path primary; MicroPython is optional only if already set up, and needs the kit's myservo.py copied to the board alongside the main file." ], "steps": [ "Seat the ESP32-S3 on the GPIO extension board and keep USB unplugged while you wire.", "Push a jumper into each of the servo's three sockets — orange, red, and brown.", "Run the orange signal wire to GPIO 21.", "Run the red wire to 5V and the brown wire to GND.", "Press a horn onto the servo's shaft so you can see it move.", "Compare every wire to the chart before you plug in USB.", "Open Sketch_17.1_Servo_Sweep.ino in Arduino IDE and upload it.", "Watch the horn sweep from one end of its travel to the other and back." ], "codeFocus": { "arduino": [ { "line": "ledcAttachChannel(pin, SERVO_FRQ, SERVO_BIT, SERVO_CHN)", "explanation": "Sets GPIO 21 switching at 50 Hz with 12-bit precision — the frame rate a servo expects." }, { "line": "map(angle, 0, 180, 103, 512)", "explanation": "Translates degrees into pulse counts — 103 counts for 0° up to 512 counts for 180°." }, { "line": "ledcWrite(SERVO_PIN, pwm_value)", "explanation": "Sends a pulse of that width every 20 ms; the servo turns until its shaft matches." } ], "micropython": [ { "line": "servo=myServo(21)", "explanation": "Builds the kit's servo helper on GPIO 21 — the same pin as the Arduino sketch." }, { "line": "servo.myServoWriteAngle(i)", "explanation": "Hands the helper an angle in degrees; it works out the pulse width for you." } ] }, "theoryModel": { "plainLanguage": "A servo reads the width of a repeating pulse and turns its shaft to the matching angle; the sketch only counts degrees and lets map() translate.", "formula": "angle = pulse width — 0.5 ms is 0° · 1.5 ms is 90° · 2.5 ms is 180°", "notes": [ { "title": "Where 103 and 512 come from", "body": "At 50 Hz and 12 bits, each 20 ms frame is 4096 counts — so 103 counts lasts about 0.5 ms and 512 counts about 2.5 ms, the two ends of the servo's travel." }, { "title": "A straight line of angles", "body": "The mapping is linear — 0.5 ms sits at 0°, 1.5 ms at 90°, 2.5 ms at 180°, and every angle between gets its own width." } ] }, "test": { "expectedOutputExample": [ "The horn glides smoothly from 0° all the way round to 180°.", "It reverses and glides back, then repeats — about 1.8 seconds each way.", "The pace is steady, like a metronome." ], "successCriteria": "A soft hum while it moves is normal. Each sweep should be one continuous glide, never a twitchy stutter." }, "troubleshooting": [ { "symptom": "Horn twitches or judders", "firstChecks": [ "Power the servo from the 5V pin with its own jumper — a GPIO can't feed a motor." ] }, { "symptom": "Sweeps once, then jams at an end", "firstChecks": [ "The horn is hitting something — pull it off the shaft and refit it clear." ] }, { "symptom": "No motion at all", "firstChecks": [ "Check the orange signal wire on GPIO 21, then the red and brown power pair." ] }, { "symptom": "Board resets mid-sweep", "firstChecks": [ "The USB supply is weak — unplug other loads from the board." ] } ], "challenge": "Sweep a half-arc, rest at each end like a lighthouse, then hunt for the smallest angle step your servo visibly answers.", "logbookPrompts": [ "Where did the horn stop on your half-arc, and did it match your prediction?", "How did the one-second rest change the feel of the sweep?", "What was the smallest angle step your servo visibly moved?" ] }