Unit G - ESP32

33. Introducing the ESP32 Family

Meet ESP32, ESP32-C3, ESP32-C5, ESP32-C6 and ESP32-P4, compare them with the Uno, and install Espressif support in Arduino IDE 2.

Estimated time 2-3 hours

Learning outcomes

Explain how ESP32-class boards differ from Arduino Uno R3
Compare classic ESP32, ESP32-C3, ESP32-C5, ESP32-C6 and ESP32-P4 at a high level
Add the Espressif ESP32 board package in Arduino IDE 2
Select a matching board definition and upload a first sketch
Apply 3.3 V I/O safety when moving from 5 V Uno labs

Parts and preparation

Arduino IDE 2, USB data cable, and one ESP32-family development board (classic ESP32 DevKit, C3, C5, C6 or P4). Optional: LED + series resistor rated for 3.3 V logic.

Before power: inspect wiring, confirm supply voltage and ensure all connected circuits share GND.

Introducing the ESP32 Family instructional connection diagram

What is the ESP32 family?

ESP32 is a family of microcontrollers from Espressif. Most members are used for Wi-Fi and Bluetooth projects; ESP32-P4 is the high-performance HMI / edge-compute branch and does not include on-chip Wi-Fi or Bluetooth. Unlike the classic Uno R3, you program these boards from Arduino IDE with the Espressif board package.

This unit introduces the family after you already understand Uno pins, sketches and safe wiring. Later ESP32 projects build on that foundation - they are not a replacement for the Uno labs in Units A-F.

ESP32 versus Arduino Uno R3

Same IDE workflow idea (setup/loop), very different hardware. Treat voltage and pin maps carefully when you switch boards.

Feature	Arduino Uno R3	Typical ESP32-family board
Maker / MCU	Arduino / ATmega328P (8-bit AVR)	Espressif / ESP32-class SoC
CPU class	16 MHz single core	Much faster; Xtensa or RISC-V (single- or dual-core)
Memory	32 KB Flash, 2 KB SRAM	Megabytes of Flash, hundreds of KB SRAM (varies by module)
Logic voltage	5 V I/O	3.3 V I/O - do not feed 5 V into pins
Wi-Fi / Bluetooth	None on-board	Most chips: Wi-Fi and usually Bluetooth; ESP32-P4 needs a companion radio for wireless
ADC	6 × 10-bit (A0-A5)	Multiple ADC channels; check the module pinout
USB / programming	USB-B serial bridge	USB-UART or native USB-C (board-dependent)
IDE support	Arduino AVR Boards	esp32 by Espressif Systems (Board Manager)
Shields / 5 V modules	Uno ecosystem	Often need level shifting or 3.3 V-safe modules

Classic ESP32 (DevKit / WROOM class)

The original ESP32 (often sold as ESP32-DevKitC or ESP32-WROOM modules) uses Xtensa dual-core CPUs with 2.4 GHz Wi-Fi and Bluetooth Classic/BLE. It is the most common "ESP32" learners mean. Pin labels are module-specific - always use your board's silkscreen and datasheet, not Uno D-numbers. The example photo is a common 38-pin DevKit V1 style board (ESP-WROOM-32, Micro-USB).

Classic ESP32 DevKit V1 38-pin development board — Classic ESP32 DevKit / WROOM example - confirm GPIO numbers on your silkscreen before wiring; pick ESP32 Dev Module in the IDE.Photo: Mantech ESP-32-38-PIN.

ESP32-C3

ESP32-C3 is a cost-focused RISC-V single-core chip with 2.4 GHz Wi-Fi 4 and Bluetooth LE. It is a strong budget step into Wi-Fi when you do not need the dual-core classic ESP32 or Thread/Zigbee radios. The example photo is a Waveshare ESP32-C3-Zero - a compact USB-C board; always match the IDE board entry and GPIO labels to your module.

ESP32-C5

ESP32-C5 adds dual-band Wi-Fi 6 (2.4 GHz and 5 GHz) plus Bluetooth LE and IEEE 802.15.4 (useful for Matter / Thread-style IoT). Choose C5 when 5 GHz Wi-Fi or dual-band connectivity matters. The example photo is a Waveshare ESP32-C5-WIFI6-KIT (N16R4 class module).

ESP32-C6

ESP32-C6 is a RISC-V IoT SoC with 2.4 GHz Wi-Fi 6, Bluetooth LE, and IEEE 802.15.4 for Zigbee / Thread / Matter-oriented designs. It is a common choice for modern smart-home nodes that need Wi-Fi 6 and 802.15.4 without 5 GHz. The example photo is a DFRobot FireBeetle 2 ESP32-C6.

ESP32-P4

ESP32-P4 is Espressif's high-performance RISC-V SoC for rich human-machine interfaces and edge compute: dual-core CPU, MIPI-CSI camera and MIPI-DSI display paths, USB 2.0 HS, and media helpers such as H.264 encode. The P4 itself has no on-chip Wi-Fi or Bluetooth - many boards add a companion radio (often an ESP32-C6). The example photo is a DFRobot FireBeetle 2 ESP32-P4 with onboard MIPI CSI/DSI and a C6 co-processor for Wi-Fi 6. Choose P4 for displays, cameras and heavier local processing; choose a C-series or classic ESP32 when you only need a simple Wi-Fi node.

ESP32 versions at a glance

High-level comparison for course selection. Exact Flash/SRAM and pin counts depend on the module and vendor board.

SoC	CPU	Wi-Fi	Bluetooth	802.15.4 / Matter-oriented	Typical use
ESP32 (classic)	Xtensa dual-core	Wi-Fi 4 (2.4 GHz)	BT Classic + BLE	No	General Wi-Fi projects, largest community examples
ESP32-C3	RISC-V single-core	Wi-Fi 4 (2.4 GHz)	BLE	No	Budget Wi-Fi + BLE nodes
ESP32-C5	RISC-V	Wi-Fi 6 dual-band (2.4 + 5 GHz)	BLE	Yes (IEEE 802.15.4)	Dual-band / 5 GHz Wi-Fi IoT
ESP32-C6	RISC-V single-core	Wi-Fi 6 (2.4 GHz)	BLE	Yes (Zigbee/Thread/Matter path)	Smart-home / Matter-class nodes
ESP32-P4	RISC-V dual-core (high perf.)	No on-chip (companion radio)	No on-chip (companion radio)	Via companion if fitted	HMI, MIPI camera/display, edge compute

Add ESP32 support in Arduino IDE 2

Install Espressif’s official board package once, then pick the board that matches your hardware.

Step	Action
1	Open File → Preferences (Windows/Linux) or Arduino IDE → Settings (macOS)
2	In Additional Board Manager URLs add: https://espressif.github.io/arduino-esp32/package_esp32_index.json
3	Open Boards Manager; search esp32; install “esp32 by Espressif Systems”
4	Tools → Board → esp32 → choose a match (e.g. ESP32 Dev Module, ESP32C3 / C5 / C6 Dev Module, or ESP32P4 Dev Module)
5	Tools → Port → select the COM/tty port that appears when the board is plugged in
6	Upload Blink or this lesson’s sketch; if upload fails, try a data USB cable and the board’s BOOT button if required

3.3 V safety when leaving the Uno

ESP32-family GPIO is 3.3 V. Never connect a 5 V Uno output directly into an ESP32 input. Many “5 V” sensors need level shifting or a 3.3 V-safe variant. Power the board only as the module documentation allows (often 5 V on USB, 3.3 V on the chip).

Wiring and safe build sequence

Connect the ESP32 board with a USB data cable
Install the Espressif board package using the steps in this lesson
Select the correct board entry and port before upload
If using an external LED, use a series resistor and a GPIO that is safe on your module (LED_BUILTIN if provided)
Keep all external logic at 3.3 V-compatible levels

Power rule: switch off before moving wires. Arduino I/O pins are control signals; high-current loads require a driver and suitable external supply.

Worked sketch

Download .ino sketch

// First ESP32 sketch - confirm board + port selection in the IDE.
// LED_BUILTIN works on many DevKits; if not, set LED_PIN to a labelled GPIO.

#ifndef LED_BUILTIN
#define LED_BUILTIN 2
#endif

const int LED_PIN = LED_BUILTIN;

void setup() {
  pinMode(LED_PIN, OUTPUT);
  Serial.begin(115200);
  delay(500);
  Serial.println("ESP32 family board ready");
}

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

How the code works

Many ESP32 boards use 115200 baud for Serial by default in examples - match the Serial Monitor.
LED_BUILTIN is not identical on every clone; check the silkscreen if the LED never blinks.
Upload uses the Espressif toolchain from Board Manager, not the Uno AVR core.

Test and record evidence

Expected result: The sketch uploads to the selected ESP32-family board. Serial prints ready/on/off messages and the on-board or wired LED blinks if the pin is correct.

Practical evidence checklist

Labelled wiring or block diagram Uploaded sketch and observed result At least one measured/tested value Fault or improvement recorded in logbook

Common faults and checks

Board package missing: confirm the Additional Board Manager URL and install esp32 by Espressif Systems.
Wrong board selected: classic ESP32 vs C3/C5/C6/P4 need different Board menu entries.
No port: data cable, drivers, or try another USB socket.
Upload fails at connect: hold BOOT while uploading on some boards, then release.
LED silent: change LED_PIN to the GPIO labelled on your board.
P4 board has no Wi-Fi in sketches: expected unless a companion radio (e.g. C6) is on the module and configured.

Extension challenge: Document your exact board name, IDE Board menu selection, and one measured 3.3 V rail reading relative to GND.

Check your understanding

Q1. What is the usual I/O voltage class for ESP32 pins compared with Uno R3?

Show answer

ESP32 is 3.3 V; Uno R3 is 5 V.

Q2. Which feature do most ESP32 Wi-Fi chips add that classic Uno R3 lacks on-board?

Show answer

Wi-Fi (and usually Bluetooth). ESP32-P4 is the exception: no on-chip radio.

Q3. What Board Manager package author should you install for ESP32 in Arduino IDE?

Show answer

Espressif Systems (package name esp32).

Q4. Name one difference between ESP32-C3 and ESP32-C6 at course level.

Show answer

Examples: C3 uses Wi-Fi 4; C6 adds Wi-Fi 6 and 802.15.4 for Zigbee/Thread/Matter-oriented use.

Q5. What is ESP32-P4 mainly for, and what does it lack on-chip?

Show answer

High-performance HMI / camera-display / edge compute; it has no on-chip Wi-Fi or Bluetooth (companion radio if wireless is needed).

Q6. Why might a 5 V sensor output be unsafe on ESP32?

Show answer

It can over-voltage a 3.3 V GPIO without level shifting.