ESP32-S3 board
The brain that runs your uploaded sketch.
01 First, know the pieces
What you need
Six things, and most of them are old friends from earlier days. Tap Define on any part you haven't met — the answer opens as a field note you can read and dismiss without losing your place.
GPIO extension board
Spreads the pins into rows you can reach and label.
Rotary potentiometer
The knob — its middle pin picks off any voltage between its two ends.
LED
The light you'll shade — it only works one way round.
220 Ω resistor
Sits in series with the LED to keep the current gentle.
5 jumper wires
Temporary, solder-free connections.
02 Make the physical circuit
Chart the circuit
The official Freenove diagram is your chart — schematic on top, the same circuit built on a breadboard below. Click it to enlarge. Two small circuits share the board today, so check the knob's side and the LED's side separately.
Pot middle pin
→GPIO 1
The board reads the knob's voltage here.
Pot outer pin
→3.3V
Gives the knob its top voltage.
Pot other outer pin
→GND
Gives the knob its bottom voltage.
LED long leg (+)
→GPIO 14 via 220 Ω
This pin shades the LED with PWM.
LED short leg (−)
→GND
Completes the LED's path back to zero volts.
Mind the LED's legs. The LED only lights one way round — long leg toward GPIO 14 through the 220 Ω resistor, short leg to ground. Unplug USB before you move any wire.
03 One action at a time
Build it
This is the main path — you can finish the day without opening a single field note. Tap each step as you go to keep your place.
0 / 9 done
Seat the ESP32-S3 on the GPIO extension board and keep USB unplugged while you wire.
Stand the potentiometer on the breadboard so each of its three pins lands in its own row.
Wire one outer pot pin to 3.3V and the other outer pin to GND.
Run the pot's middle pin to GPIO 1 — this is the wire the board reads.
Place the LED so its long leg (+) is on the GPIO 14 side and its short leg (−) heads toward ground.
Put the 220 Ω resistor in series between GPIO 14 and the LED's long leg.
Compare every wire to the chart before you plug in USB.
Open
Sketch_10.1_SoftLight.inoin Arduino IDE and upload it.Turn the knob slowly from end to end and watch the LED follow your hand.
04 Read just enough code
Read the code
The whole sketch is four working lines. One line sets up PWM on the LED's pin; the loop reads the knob and hands that number straight to the light. Switch to MicroPython if you'd rather see the same idea in Python — the wiring never changes.
#define PIN_ANALOG_IN 1
#define PIN_LED 14
#define CHAN 0
void setup() {
ledcAttachChannel(PIN_LED, 1000, 12, CHAN);
}
void loop() {
int adcVal = analogRead(PIN_ANALOG_IN); //read adc
int pwmVal = adcVal; // adcVal re-map to pwmVal
ledcWrite(PIN_LED, pwmVal); // set the pulse width.
delay(10);
}ledcAttachChannel(PIN_LED, 1000, 12, CHAN)Sets up PWM on GPIO 14 at 12-bit resolution, so brightness runs 0 to 4095 — the same span the ADC produces. analogRead(PIN_ANALOG_IN)Reads the knob's voltage on GPIO 1 as a number from 0 to 4095. ledcWrite(PIN_LED, pwmVal)Sets the LED's duty to that number. The two scales match, so the raw reading passes straight through as a brightness — the "re-map" comment overstates what this line does. Optional side path · same circuit
pwm =PWM(Pin(14,Pin.OUT),1000)
adc=ADC(Pin(1))
adc.atten(ADC.ATTN_11DB)
adc.width(ADC.WIDTH_12BIT)
adcValue=adc.read()
pwmValue=remap(adcValue,0,4095,0,1023)
pwm.duty(pwmValue)adc.width(ADC.WIDTH_12BIT)Sets the ADC to 12 bits so readings run 0 to 4095 — the same span the Arduino sketch reads.remap(adcValue,0,4095,0,1023)MicroPython's duty here is 10-bit, so the reading is squeezed from 0–4095 down to 0–1023 before it drives the LED.Same pins, same wiring. MicroPython's duty runs 0–1023, so this version remaps the reading down before writing it; the Arduino sketch matches the two resolutions so the number passes straight through. Run it in Thonny if MicroPython is set up; otherwise skip it — it should never block the Arduino-first path.
05 Understand, don't memorise
One loop from hand to light
Everything you've learned about pins joins up today. Day 13 turned a voltage into a number; Day 7 turned a number into brightness. This sketch links the two, many times a second.
Knob in
analogRead turns the wiper's voltage into a number from 0 to 4095.
One variable
pwmVal takes the ADC number straight across — both scales run 0 to 4095.
LED out
ledcWrite sets the duty so the LED holds that brightness.
Every 10 ms
The loop runs again at once so the light tracks your hand as you turn.
The model
knob voltage → ADC number → PWM duty → brightness
Why there's no map() call
The sketch sets the PWM to 12 bits on purpose. Both scales run 0 to 4095, so the ADC reading is already a valid duty and passes through untouched. When the scales differ — as in the MicroPython version — you remap first.
What the potentiometer is doing
Its two outer pins hold 3.3V and 0V across a resistive track, and the middle pin slides along that track as you turn — picking off any voltage in between.
06 Know it worked
Test & debug
Nothing prints to the screen today — the proof is the LED under your fingertips.
What you should see
- Turn the knob to one end — the LED sits dark.
- Turn it to the other end — the LED reaches full brightness.
- Everywhere in between, the brightness follows the knob smoothly, with no jumps or dead spots.
Which end is dark depends on which outer pin you wired to GND — either way round is a working circuit.
If it doesn't
- LED stuck at full or stuck dark? Check the pot's middle-pin wire — it must reach GPIO 1.
- Turning the knob changes nothing? Check the outer pot pins — one to 3.3V, one to GND.
- LED dark at every knob position? Check the LED's direction and the 220 Ω resistor on the GPIO 14 side.
- Upload fails? Swap in a data-capable USB cable.
07 Make the idea yours
Try this: bend the response
Same working circuit, one line to play with — the line that carries the number across. It fits inside today's 20 minutes.
Reverse the direction
Change the middle line to int pwmVal = 4095 - adcVal; and upload. The light now fades the opposite way as you turn — the same chain, flipped in one subtraction.
Make a three-step lamp
Replace the pass-through with if-bands — below 1000 write 0, up to 3000 write 2048, above that write 4095 — and feel the knob become an off / half / full switch.
Logbook
08 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-DAY15-SOFTLIGHT
Context packet
How the agent should behave: guide one physical connection at a time, wait for you to confirm, explain terms on request, and always check wiring, board, port, and USB before changing code.