setup()
Runs once. Use it for pinMode(), Serial.begin(), library setup, and device initialization.
Arduino sample guide
roboda-sample-0041 - RGB LED 02
Practice this Arduino feature with a verified Roboda sketch.
Step-by-step build
Blend three PWM channels for status colors and visual feedback.
1
Read the constants at the top of the sketch.
2
Wire the pins exactly as listed in the pin map.
3
Upload or compile once before changing values.
4
Change one value at a time and watch Serial Monitor or the output device.
Important code parts
These are the sections learners should understand before changing the sketch.
loop()
Runs repeatedly. Put the behavior you want the robot or circuit to keep doing here.
constants
Named pins and thresholds make the sketch easier to adapt to another board or wiring layout.
Pin mapping for this sample
Use this first table for the exact sample wiring, then use the board-family table when moving the sketch to another Arduino board.
| Code name | Sample pin | Mode | Connect to | Note |
|---|---|---|---|---|
| RGB channels | D9, D10, D11 | PWM OUTPUT | Red, green, blue LED legs through resistors | Use common-anode LEDs with inverted values if needed. |
Arduino board pin reference
The code names stay the same; only the physical board pins may change by family. Always confirm with the board silkscreen when using clones or special variants.
| Board family | Digital | PWM | Analog | I2C | SPI | Interrupt |
|---|---|---|---|---|---|---|
| Uno / Nano / Pro MiniDefault target for these samples. | D0-D13 | D3, D5, D6, D9, D10, D11 | A0-A5 | A4 SDA, A5 SCL | D10 SS, D11 MOSI, D12 MISO, D13 SCK / ICSP | D2, D3 |
| Mega 2560Best for many sensors or multiple serial ports. | D0-D53 | D2-D13, D44-D46 | A0-A15 | D20 SDA, D21 SCL | D50 MISO, D51 MOSI, D52 SCK, D53 SS / ICSP | D2, D3, D18, D19, D20, D21 |
| Leonardo / MicroUSB serial can behave differently because the main MCU handles USB. | D0-D13 | D3, D5, D6, D9, D10, D11, D13 | A0-A5 plus extra analog-capable pins by board | D2 SDA, D3 SCL | ICSP header | D0, D1, D2, D3, D7 |
| Nano Every / Uno WiFi Rev2Check the board package pinout for exact PWM labels. | D0-D13 | PWM-marked digital pins | A0-A7 on Nano Every, A0-A5 on Uno WiFi Rev2 | SDA/SCL marked pins | ICSP/SPI marked pins | Use pins supported by digitalPinToInterrupt() |
| Uno R4 Minima / Uno R4 WiFi5V logic board; still confirm shield/library compatibility. | D0-D13 | PWM-marked digital pins | A0-A5 | SDA/SCL marked pins | ICSP/SPI marked pins | Use digitalPinToInterrupt(pin) |
| Due3.3V logic only; protect pins from 5V sensors. | D0-D53 | PWM-marked digital pins | A0-A11 | SDA/SCL and SDA1/SCL1 | SPI header | Use digitalPinToInterrupt(pin) |
| MKR / Nano 33 family3.3V logic. Some AVR-only libraries may need alternatives. | Board-marked digital pins | PWM-marked pins | Board-marked analog pins | SDA/SCL marked pins | SPI marked pins | Use digitalPinToInterrupt(pin) |
Full sample code
/*
Roboda verified Arduino sample 0041
Feature: RGB LED
Generated for online build, classroom practice, and hardware upload testing.
*/
const byte redPin = 9;
const byte greenPin = 10;
const byte bluePin = 11;
byte hueStep = 0;
void setup() {
pinMode(redPin, OUTPUT);
pinMode(greenPin, OUTPUT);
pinMode(bluePin, OUTPUT);
}
void loop() {
analogWrite(redPin, hueStep);
analogWrite(greenPin, 255 - hueStep);
analogWrite(bluePin, (hueStep / 2) + 1);
hueStep += 5;
delay(38);
}
Teacher notes
- Compile the sample before changing wiring or constants.
- When changing boards, keep the code names the same and update only the pin number constants.
- For 3.3V boards, level-shift 5V sensors and modules before connecting signal pins.
- Use the first compiler error and the Roboda diagnostic suggestion before fixing later warnings.