{ "schema": "tinyskiff.lessonPacket.v0", "lessonCode": "TSK-DAY09-RGB", "course": "TinySkiff ESP32-S3 Lab", "day": 9, "title": "Mix any colour from three lights", "status": "published", "learnerProfile": "adult beginner; curious and capable; no electronics assumed", "estimatedTimeMinutes": 25, "mission": "Wire an RGB LED — three tiny lights in one dome — to three PWM pins, upload the Arduino sketch, and watch the board mix red, green, and blue into a stream of random colours you never wired by hand.", "mainPath": "Arduino/C++", "optionalSidePath": "MicroPython", "sourceMetadata": { "officialPdf": "source/Freenove_Super_Starter_Kit_for_ESP32_S3-main/C/C_Tutorial.pdf", "chapter": "Chapter 5 RGB LED", "page": 72, "arduinoSketch": "source/Freenove_Super_Starter_Kit_for_ESP32_S3-main/C/Sketches/Sketch_05.1_RandomColorLight/Sketch_05.1_RandomColorLight.ino", "arduinoVariant": "source/Freenove_Super_Starter_Kit_for_ESP32_S3-main/C/Sketches/Sketch_05.2_GradientColorLight/Sketch_05.2_GradientColorLight.ino", "micropythonFile": "source/Freenove_Super_Starter_Kit_for_ESP32_S3-main/Python/Python_Codes/05.1_RandomColorLight/RandomColorLight.py", "imageAsset": "docs/course/assets/day-09/circuit-page-72.png", "imageAlt": "Official Freenove circuit for the RGB LED: a red, a green, and a blue leg each running through its own 220 ohm resistor to a separate GPIO pin, with the long common pin joined to 3.3 volts, 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": "RGB LED", "imageAsset": "docs/course/assets/shared/item-rgb-led.png", "explanation": "An RGB LED is three tiny LEDs — red, green, and blue — in one dome. Set each one's brightness with PWM and your eye blends them into a single colour. All off is dark; all full is white; everything else is a mix — the same trick a screen uses." }, { "name": "3 × 220 Ω resistors", "imageAsset": "docs/course/assets/shared/item-resistor.png", "explanation": "A resistor limits how much current flows. Placed in series with the LED, the 220 Ω one keeps the current gentle enough to light the LED instead of burning it out. The bands of colour print its value, and it has no direction." }, { "name": "Jumper wires", "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": "Red leg (via 220 Ω)", "connectTo": "GPIO 38", "reason": "One PWM channel sets how much red shows." }, { "partPin": "Green leg (via 220 Ω)", "connectTo": "GPIO 39", "reason": "One PWM channel sets how much green shows." }, { "partPin": "Blue leg (via 220 Ω)", "connectTo": "GPIO 40", "reason": "One PWM channel sets how much blue shows." }, { "partPin": "Common (long) pin", "connectTo": "3.3V", "reason": "All three share this positive pin so a colour lights when its pin goes LOW." } ], "coachInstructions": [ "Guide one physical connection at a time and wait for learner confirmation before proceeding.", "Stress that this is a common-anode LED — the long common pin goes to 3.3V, not to ground.", "Explain the 255 minus value inversion only when asked; it is why a colour lights when its pin goes LOW.", "If only one colour appears, check that colour's 220 Ω resistor and GPIO wire before changing code.", "If nothing lights, check the common pin reaches 3.3V; if a colour is stuck on, suspect common-anode wiring or the wrong leg.", "Keep the Arduino path primary; MicroPython is optional only if already set up." ], "steps": [ "Seat the ESP32-S3 on the GPIO extension board and keep USB unplugged while you wire.", "Find the RGB LED's long pin — that's the common one shared by all three colours.", "Wire the red leg through a 220 Ω resistor to GPIO 38.", "Wire the green leg through a 220 Ω resistor to GPIO 39.", "Wire the blue leg through a 220 Ω resistor to GPIO 40.", "Run the long common pin to 3.3V, not to ground.", "Compare every wire to the chart before you plug in USB.", "Open Sketch_05.1_RandomColorLight.ino in Arduino IDE and upload it.", "Watch the dome change colour again and again." ], "codeFocus": { "arduino": [ { "line": "const byte ledPins[] = {38, 39, 40}", "explanation": "The three pins are the red, green, and blue legs in that order." }, { "line": "ledcWrite(ledPins[0], 255 - red)", "explanation": "Writes 255 minus the value because this common-anode LED lights when its pin goes LOW." }, { "line": "red = random(0, 256)", "explanation": "Each colour gets a fresh brightness from 0 to 255, and setting all three at once mixes the shade." } ], "micropython": [ { "line": "pwm0.duty(1023 - r)", "explanation": "MicroPython's duty here is 10-bit, so it inverts with 1023 minus the value instead of 255." } ] }, "theoryModel": { "plainLanguage": "Set a brightness for red, green, and blue at once, and your eye blends them into a single colour.", "formula": "colour = red + green + blue at chosen brightnesses", "notes": [ { "title": "Why the code inverts each value", "body": "The common pin sits at 3.3V, so a colour is brightest when its own pin is pulled LOW. Writing 255 minus the brightness flips the scale so bigger still means brighter." }, { "title": "Three lights in one part", "body": "An RGB LED is three coloured LEDs packaged together, each with its own leg and a shared common pin." } ] }, "test": { "expectedOutputExample": [ "The RGB LED glows a colour.", "Every fraction of a second it jumps to a new random colour.", "It keeps changing for as long as the board has power." ], "successCriteria": "The colours look random on purpose — each one is a fresh mix of red, green, and blue." }, "troubleshooting": [ { "symptom": "Only one colour ever appears", "firstChecks": [ "Check that colour's 220 Ω resistor and its GPIO wire — the other two legs may not be reaching their pins." ] }, { "symptom": "Nothing lights at all", "firstChecks": [ "Check the common pin — it goes to 3.3V, not to ground." ] }, { "symptom": "A colour is stuck full-on", "firstChecks": [ "Suspect the common-anode wiring or the wrong leg on that pin." ] }, { "symptom": "Upload fails", "firstChecks": [ "Swap in a data-capable USB cable." ] } ], "challenge": "Choose a colour that would mean ready or warning, record its red, green, and blue numbers, then try the gradient variant.", "logbookPrompts": [ "What red, green, and blue numbers did you pick for your status colour?", "How did the gradient sketch feel different from the random one?", "What in a real gadget would you want an RGB light to tell you?" ] }