Lesson 3 of 4

Dim the LED with a knob

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// Dim an LED from a potentiometer const uint8_t POT_PIN = 1; // wiper of the 10 kΩ pot, GPIO1 const uint8_t LED_PIN = 4; const uint8_t RGB_PIN = 38; const uint32_t PWM_HZ = 5000; const uint8_t PWM_BITS = 8; // 8 bits: duty 0 to 255 unsigned long lastPrint = 0; void setup() { Serial.begin(115200); analogReadResolution(12); // 12-bit ADC: raw 0 to 4095 ledcAttach(LED_PIN, PWM_HZ, PWM_BITS); // 3.x API: attach PWM by pin } void loop() { int raw = analogRead(POT_PIN); // 0 at one end of the knob, 4095 at the other int mv = analogReadMilliVolts(POT_PIN); int duty = raw / 16; // 4095 / 16 = 255, full duty ledcWrite(LED_PIN, duty); rgbLedWrite(RGB_PIN, duty / 4, 0, (255 - duty) / 4); if (millis() - lastPrint >= 250) { lastPrint = millis(); Serial.printf("pot %d (%d mV) -> duty %d\n", raw, mv, duty); } delay(10); }

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A potentiometer on GPIO1 sets the brightness of the LED on GPIO4. The ESP32-S3 reads the wiper with a 12-bit ADC and drives the LED with LEDC PWM.

A 12-bit reading turned into an 8-bit duty
The 3.x LEDC API, attached by pin
The wiper voltage, printed in millivolts

Pin	Connects to	What it does
`GPIO1`	Potentiometer wiper	Analog input
`GPIO4`	330 Ω, then the LED	PWM output
`3V3`	One end of the potentiometer	3.3 V reference

Wire it in

Sensors and actuators this board drives, with the real connections.

All 10 parts on the ESP32-S3-DevKitC-1 page

Dim the LED with a knob

Try it yourself

Serial monitor

Checks

Break it

Inputs

Parameters

Wire it in

Dim the LED with a knob

Try it yourself

Serial monitor

Checks

Break it

Inputs

Parameters

Wire it in