ESP32-S3 board
The board — and the small onboard LED you'll blink.
01 First, know the pieces
What you need
Almost nothing today — the LED you'll blink is already on the board. Tap Define on anything unfamiliar; the answer opens as a field note.
Arduino IDE
Opens the sketch, uploads it, and reports "Done uploading."
Official sketch
Sketch_01.1_Blink.ino
02 One action at a time
Build it
The whole day is upload-and-watch. Tap each step as you go to keep your place — you can finish without opening a single field note.
0 / 5 done
Plug the ESP32-S3 into your computer with a data-capable USB-C cable.
In Arduino IDE, select your ESP32-S3 board and the port it appears on.
Open
Sketch_01.1_Blink.ino.Press Upload and wait for the IDE to say
Done uploading.Watch the small onboard LED near the chip start to blink.
03 Read just enough code
Read the code
Five short lines. Two of them run once to get ready; three of them repeat forever. That's the shape of nearly every Arduino sketch.
#define LED_BUILTIN 2
void setup() {
pinMode(LED_BUILTIN, OUTPUT);
}
void loop() {
digitalWrite(LED_BUILTIN, HIGH); // on
delay(1000); // wait 1 second
digitalWrite(LED_BUILTIN, LOW); // off
delay(1000); // wait 1 second
}#define LED_BUILTIN 2Names the onboard LED's pin so the rest of the sketch reads plainly. pinMode(LED_BUILTIN, OUTPUT)Runs once in setup() to say this pin will push signal out. digitalWrite(LED_BUILTIN, HIGH)Turns the LED on; LOW turns it off. delay(1000)Holds that state for one second before the next line. 04 Understand, don't memorise
Why it blinks
There's no magic here — just two functions the board runs in a fixed order, over and over.
setup()
The board prepares the pin as an output.
loop()
Everything inside runs again and again without stopping.
HIGH + delay
Voltage on the pin lights the LED; delay holds it there.
LOW + delay
Voltage off; delay holds the dark before it repeats.
The rhythm
one blink = 1 s on + 1 s off = a 2-second cycle
setup() vs loop()
setup() gets things ready a single time; loop() is the part that keeps running.
05 Know it worked
Test & debug
Nothing prints to the screen today — the proof is on the board itself.
What you should see
- The small onboard LED turns on for one second.
- Then off for one second.
- Then it repeats, steady, for as long as the board has power.
The larger LED that stays lit is the power light — look for the smaller one that blinks.
If it doesn't
- Nothing blinks? Confirm the right board and port are selected, then upload again.
- No `Done uploading`? Try a different USB-C cable — some are charge-only and carry no data.
- One LED glows steady? That's the power LED. The blink is a second, smaller LED near the chip.
06 Make the idea yours
Try this: find a heartbeat
Same sketch, one small change: the two delay numbers. Timing is what gives a blink its character.
Speed it up
Set both delay(1000) lines to delay(200) and upload. Notice how different 200 feels.
Find a heartbeat
Adjust the two numbers until the blink feels like a resting pulse. Write down what you landed on.
Logbook
07 Learn it with a hand on the tiller
Coach me through it
Every lesson ships with a code and a machine-readable packet, so an agent can guide you with full context.
Lesson code
TSK-DAY03-BLINK
Context packet
How the agent should behave: keep it to upload-and-watch, check board and port and cable before touching code, and explain setup()/loop() and the delay numbers on request.