ESP32 Starter Kit

1. Setup checklist (do this once)

• Install Arduino IDE 2.x or PlatformIO
• Add ESP32 board support (Espressif boards package / PlatformIO espressif32)
• Install USB drivers if needed: CP210x or CH340 (depends on your DevKit)
• Use a USB data cable (charge-only cables cause 80% of “no port” tickets)
• Select the correct board profile + COM / /dev/ttyUSB0 / cu.usbserial-*
• Open Serial Monitor at 115200 baud

Board notes

• ESP32-WROOM DevKit and ESP32-S3 DevKit both work; pin numbers differ.
• LED_BUILTIN may be GPIO 2, 8, or an RGB addressable LED on S3 boards — if blink “does nothing,” try GPIO 2 explicitly.
• Many boards need you to hold BOOT while uploading if auto-reset fails.

2. Parts list (BOM)

Shopping shortlist on the site: averyjparker.com/gear (affiliate disclosure on that page).

3. Project 1 — Blink + Serial “hello”

Goal: Prove flash + USB serial work before sensors or Wi‑Fi.

Wiring

None required if you use LED_BUILTIN. USB powers the board.

Sketch

// Project 1 — Blink + Serial
// If LED_BUILTIN does nothing on your clone, try: const int LED = 2;

void setup() {
  Serial.begin(115200);
  delay(500);
  pinMode(LED_BUILTIN, OUTPUT);
  Serial.println("ESP32 starter kit — Project 1 ready");
}

void loop() {
  digitalWrite(LED_BUILTIN, HIGH);
  Serial.println("LED on");
  delay(500);
  digitalWrite(LED_BUILTIN, LOW);
  Serial.println("LED off");
  delay(500);
}

Expected result

• Onboard LED toggles ~1 Hz
• Serial prints alternating LED on / LED off

Troubleshooting

• No serial text: baud 115200; correct port; press RESET after open monitor
• Upload failed: hold BOOT; lower upload speed to 115200; try another cable
• No LED: set pin explicitly to 2 (or check your board’s silkscreen)

Done when

You can reflash freely and see serial output without fighting the port.

4. Project 2 — Button with pull-up

Goal: Read a digital input with debounce (foundation for every “if button then…” project).

Wiring

• Option A (easiest): use the onboard BOOT button (often GPIO 0) — no wires
• Option B: external button between GPIO 0 (or any free GPIO) and GND

Use INPUT_PULLUP: idle = HIGH, pressed = LOW. No external pull-up resistor required.

Sketch

// Project 2 — Button + LED feedback
const int BTN = 0;          // BOOT on many DevKits
const int LED = LED_BUILTIN;

void setup() {
  Serial.begin(115200);
  pinMode(BTN, INPUT_PULLUP);
  pinMode(LED, OUTPUT);
  Serial.println("Project 2 — press button (BOOT or wired to GND)");
}

void loop() {
  static bool lastPressed = false;
  bool pressed = digitalRead(BTN) == LOW;

  digitalWrite(LED, pressed ? HIGH : LOW);

  if (pressed != lastPressed) {
    Serial.println(pressed ? "pressed" : "released");
    lastPressed = pressed;
    delay(40); // crude debounce
  }
}

Expected result

• LED follows button state
• Serial prints pressed / released once per edge (not a flood)

Troubleshooting

• Always pressed: wrong pin; short to GND; try GPIO 4 with external button instead of 0
• Chatter: increase debounce to 50–80 ms; use a cleaner mechanical switch

Done when

One clean edge per physical press/release.

5. Project 3 — External LED + resistor

Goal: Drive an external load correctly (current limiting) — the habit that prevents dead pins.

Wiring

1. GPIO 4 → 220 Ω resistor → LED anode (long leg)
2. LED cathode (short leg) → GND

Sketch

// Project 3 — External LED on GPIO 4
const int LED = 4;

void setup() {
  Serial.begin(115200);
  pinMode(LED, OUTPUT);
  Serial.println("Project 3 — external LED on GPIO 4");
}

void loop() {
  for (int i = 0; i < 3; i++) {
    digitalWrite(LED, HIGH);
    delay(150);
    digitalWrite(LED, LOW);
    delay(150);
  }
  delay(800);
  Serial.println("blink burst");
}

Expected result

External LED does a triple-blink, pause, repeat. Serial prints blink burst.

Troubleshooting

• Dim/no light: LED backwards; bad breadboard row; resistor too large
• Very bright / hot: missing resistor — unplug immediately

Done when

You can move the LED to another GPIO by changing one constant.

6. Project 4 — Temperature / humidity read

Goal: Read a real sensor on a schedule (basis for automation and logging).

Pick one path below.

Option A — DHT22 (simpler wiring for beginners)

1. DHT22 VCC → 3.3 V (some modules want 5 V — check yours)
2. DHT22 GND → GND
3. DHT22 DATA → GPIO 15
4. If module has no onboard pull-up: 4.7k–10k from DATA to 3.3 V

Install library: DHT sensor library by Adafruit (+ Adafruit Unified Sensor).

// Project 4A — DHT22 on GPIO 15
#include <DHT.h>
#define DHTPIN 15
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(115200);
  dht.begin();
  Serial.println("Project 4A — DHT22");
}

void loop() {
  delay(2500); // don't hammer the sensor
  float h = dht.readHumidity();
  float t = dht.readTemperature(); // Celsius
  if (isnan(h) || isnan(t)) {
    Serial.println("Read failed — check wiring / pull-up / power");
    return;
  }
  Serial.print("Temp C: ");
  Serial.print(t, 1);
  Serial.print("  RH %: ");
  Serial.println(h, 1);
}

Option B — BME280 over I²C

1. VCC → 3.3 V · GND → GND
2. SDA → GPIO 21 · SCL → GPIO 22 (common ESP32 defaults)

Install library: Adafruit BME280 (+ BusIO / Unified Sensor as prompted).

// Project 4B — BME280 I2C
#include <Wire.h>
#include <Adafruit_BME280.h>
Adafruit_BME280 bme;

void setup() {
  Serial.begin(115200);
  if (!bme.begin(0x76) && !bme.begin(0x77)) {
    Serial.println("BME280 not found — run I2C scan / check SDA SCL");
    while (1) delay(10);
  }
  Serial.println("Project 4B — BME280");
}

void loop() {
  Serial.print("T=");
  Serial.print(bme.readTemperature(), 1);
  Serial.print("C  P=");
  Serial.print(bme.readPressure() / 100.0F, 1);
  Serial.print("hPa  H=");
  Serial.print(bme.readHumidity(), 1);
  Serial.println("%");
  delay(3000);
}

Expected result

Stable numbers that change when you breathe on / warm the sensor. Failed reads print a clear error — not silent zeros.

Troubleshooting

• NaN / failed: power, data pin, pull-up, library mismatch (DHT11 vs DHT22)
• BME not found: try address 0x76 and 0x77; confirm 3.3 V not 5 V on some modules

Done when

You have a repeating log line you trust enough to graph later.

7. Project 5 — Relay (low-voltage only while learning)

Goal: Drive a relay module from a GPIO with a simple on/off serial control pattern.

Wiring (module side)

1. Relay module VCC → 5 V (if module is 5 V logic) or 3.3 V per module docs
2. Relay module GND → ESP32 GND (common ground required)
3. Relay module IN → GPIO 5
4. Load on the relay COM / NO terminals — low-voltage DC only for this kit (e.g. 5 V fan, LED strip segment with its own supply)

Sketch

// Project 5 — Relay on GPIO 5 (active-low friendly)
const int RELAY = 5;
const bool ACTIVE_LOW = true; // set false if your module is active-high

void relayWrite(bool on) {
  if (ACTIVE_LOW) {
    digitalWrite(RELAY, on ? LOW : HIGH);
  } else {
    digitalWrite(RELAY, on ? HIGH : LOW);
  }
}

void setup() {
  Serial.begin(115200);
  pinMode(RELAY, OUTPUT);
  relayWrite(false);
  Serial.println("Project 5 — relay demo (3s on / 3s off)");
}

void loop() {
  relayWrite(true);
  Serial.println("relay ON");
  delay(3000);
  relayWrite(false);
  Serial.println("relay OFF");
  delay(3000);
}

Combine with Project 4 (mini automation)

// Pseudo-logic you'll use in the full site guide:
// if (temperatureC > 28.0) relayWrite(true);  // e.g. fan
// else if (temperatureC < 26.0) relayWrite(false);

Full write-up: ESP32 home automation with sensors & relays.

Expected result

Relay clicks (or module LED toggles) on a 3 s cadence; serial confirms state.

Troubleshooting

• Board resets when relay fires: power the relay from a separate 5 V supply; common GND
• Logic inverted: flip ACTIVE_LOW
• No click: wrong IN pin; module needs 5 V VCC while ESP is 3.3 V signal — most opto boards still accept 3.3 V IN

Done when

You can turn a safe low-voltage load on/off without the ESP brownout-resetting.

8. Troubleshooting cheat sheet

9. What to build next

1. Site guide: ESP32 first project (expanded)
2. Home automation project
3. Pi + ESP32 mesh smart home
4. Choose Pi, ESP32, or Arduino
5. Upcoming scheduled posts

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