Arduino Uno R3

Upload, blink, and observe

Upload a known sketch, change one timing value, and use visible evidence to prove that the Uno is running the revised program.

CSTA 2026 mapping candidatesNot reviewed by CSTA

MS-PRO-PD-13ProgrammingMS-PRO-TR-19Programming

Students will

Select the correct board and port
Upload a sketch and distinguish compile, upload, and runtime behavior
Change a timing value and verify the new behavior

Evidence of success

The sketch uploads without an unresolved error
The built-in LED follows the original timing
A second upload produces the predicted revised timing

Hardware

Arduino Uno R3
USB cable
Computer with Arduino IDE or Arduino Cloud Editor

Prerequisites

Identify the Uno R3 and its USB connector
Use a classroom computer safely

Before class

Confirm the supported editor can detect one Uno R3
Check that the correct board support is available
Prepare a known-good USB data cable

Reviewed connection map

Board connection

ComputerArduino editor and known data-capable USB cable

Arduino Uno R3Correct board and port selected

LED_BUILTINOn-board output; no external circuit

Connect the Uno directly with the USB data cable.
This lesson uses the built-in LED, so no breadboard wiring is required.

Build and test

01Connect the Uno by USB and select Arduino Uno
02Open the Blink example and identify setup, loop, and LED_BUILTIN
03Verify and upload the unchanged sketch
04Observe and time the built-in LED
05Change both delay values, upload again, and compare the evidence

Read before uploading

Annotated Arduino sketch

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  digitalWrite(LED_BUILTIN, HIGH);
  delay(500);
  digitalWrite(LED_BUILTIN, LOW);
  delay(500);
}

Optional engineering record

Record evidence from this lesson

Choose the prompts that help students explain predictions, evidence, debugging, and transfer. Saving creates a new entry in this browser’s Rudi notebook.

Record your thinking — optional4 prompts

Use these prompts if they help students capture evidence, decisions, or questions. You do not need to complete every prompt or create an entry at every step.

Predict: Before you begin, what do you expect to observe when you select the correct board and port?Evidence: What evidence best demonstrates this result: The sketch uploads without an unresolved error?Debug: If you encounter “No board or port appears,” what will you check first, and why?Transfer: Where could you reuse the skill from “Upload, blink, and observe” in another classroom project?

Nothing is saved until you choose this button.

Troubleshooting

No board or port appears

Try a known data-capable USB cable, reconnect the board, and recheck the editor's board and port menus.

Upload succeeds but the timing looks unchanged

Confirm both delay values were edited, save the sketch, and upload the revised version again.

2026 middle school standards

Potential CSTA connections

Not reviewed by CSTA

These are evidence-based crosswalk candidates for curriculum review—not a claim of official alignment.

MS-PRO-PD-13

Use reference documentation in program development.

Students use board and editor documentation while selecting, compiling, and uploading a known sketch.

Lesson evidence: Successful documented upload

MS-PRO-TR-19

Use systematic strategies to test, refine, and document changes to a computing technology to meet the intended purpose.

Students isolate variables, compare observed behavior with the intended purpose, and document a revision.

Lesson evidence: Before-and-after timing evidence

View the official 2026 CSTA standardsStandard text: Computer Science Teachers Association (2026), CC BY-NC-SA 4.0.

Supporting concepts

board-tour · sketch-foundations

Sources and review

Arduino Uno R3 documentation Arduino Projects Book · CC BY-NC-SA 3.0

Starting point, not verified curriculum. Review the actual hardware, circuit, code, power requirements, and classroom conditions.

After teaching this lesson