Heltec WiFi LoRa 32(V2)

by Heltec

Improved LoRa ESP32 board with better power management - suited for off-grid and battery-powered systems.

Micro-USB

Buy · $17.90 Pinout Datasheet ↗

50.2 × 25.5 mm

ESP32

MCU

240MHz

clock

8MB

flash

520KB

SRAM

28· 18 ADC

GPIO

BLE 4.2+ WiFi

radio

Heltec WiFi LoRa 32(V2) Pinout

36 pins · 2.54 mm pitch

Pin	GPIO	Labels	Status	Capabilities	Notes
1	-	GND	ground	-
2	-	5V	power	-
3	-	Vext	power	-	switched 3.3 V output, on while GPIO21 is LOW
4	-	Vext	power	-	Vext, second pin
5	3	RXPWM	uart	uart	UART0 RX, wired to the CP2102
6	1	TXPWM	uart	uart	UART0 TX, wired to the CP2102
7	-	RSTEN	control	-	chip reset, shared with the RST button
8	0	KEY_BUILTINA11T1	strapping	adc · touch	the PRG button; strapping pin
9	22	SCLPWM	safe	i2c
10	19	MISOPWMLoRa_MISO	safe	spi
11	23	GPIO23PWM	safe	pwm
12	18	SSPWMLoRa_CS	safe	spi
13	5	SCKPWMLoRa_SCK	strapping	spi	strapping pin - LOW while flashing
14	15	A13T3PWMOLED_SCL	strapping	adc · touch	strapping pin - HIGH while flashing
15	2	A12T2PWM	strapping	adc · touch	strapping pin
16	4	A10T0PWMOLED_SDA	safe	adc · touch
17	17	GPIO17PWM	uart	uart · pwm
18	16	PWMOLED_RST	safe	-
19	-	GND	ground	-
20	-	3V3	power	-
21	-	3V3	power	-
22	36	A0	strapping	adc	input-only
23	37	GPIO37A1	strapping	adc	input-only
24	38	GPIO38A2	strapping	adc	input-only
25	39	A3	strapping	adc	input-only
26	34	A6LoRa_DIO2	strapping	adc	input-only
27	35	A7LoRa_DIO1	strapping	adc	input-only
28	32	A4T9PWM	safe	adc · touch
29	33	A5T8PWM	safe	adc · touch
30	25	LED_BUILTINA18DAC1LEDPWM	safe	adc · dac
31	26	A19DAC2PWMLoRa_DIO0	safe	adc · dac
32	27	MOSIA17T7PWMLoRa_MOSI	safe	adc · touch · spi
33	14	A16T6PWMLoRa_RST	strapping	adc · touch
34	12	A15T5PWM	strapping	adc · touch	strapping pin - LOW while flashing
35	13	A14T4PWM	strapping	adc · touch
36	21	SDAVextPWM	safe	i2c	Vext control: LOW turns the Vext rail on

Download the Heltec WiFi LoRa 32(V2) pinout Free to use and share for non-commercial work, as long as you credit espboards.dev. License.

PNG - download the Heltec WiFi LoRa 32(V2) pinout, high resolution image 4800 px wide · 1.4 MB SVG - download the Heltec WiFi LoRa 32(V2) pinout as a vector file Vector, any size · 157 KB PDF - download the Heltec WiFi LoRa 32(V2) pinout as a printable PDF A4, print ready · 535 KB

28 GPIOs broken out 5 free · 15 need care · 8 to avoid

Start with these

5 pins with no boot or system involvement

SCLGPIO22GPIO23GPIO17A4GPIO32A5GPIO33

Freely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.

Fine - with a little care

15 pins · 11 things to know

RXGPIO3 Default UART0 RX pin for USB-serial programming (console input). UART

Used for receiving data from USB-UART (programming); also pulled HIGH at boot for console communication, so using as GPIO can disrupt uploads.

TXGPIO1 Default UART0 TX pin for USB-serial programming and console. UART

Connected to on-board USB-UART for uploading and logs; drives serial output at boot, so using as GPIO can disrupt programming or console.

KEY_BUILTINGPIO0 Bootstrapping pin (enter bootloader when low); internal pull-up. Strapping

Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode.

A13GPIO15A10GPIO4PWMGPIO16 strapping pin - HIGH while flashing onboard hardware

Wired to the OLED on this board. The pin is yours if you give that up, but nothing else can share it.

A13strapping pin - HIGH while flashing
A10
PWM

A12GPIO2 Bootstrapping pin (must be low or floating at reset); internal pull-down. Strapping

If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure.

A0GPIO36 Input-only GPIO (no output); ADC1 channel 0, Hall sensor VP. Other

Cannot be used as output; only suitable for input (e.g., analog read).

GPIO37GPIO38A3GPIO39 Input-only GPIOs with ADC1 channels - no output driver Other

Cannot be used as output; only suitable for input.

GPIO37Input-only GPIO (no output); ADC1 channel 1.
GPIO38Input-only GPIO (no output); ADC1 channel 2.
A3Input-only GPIO (no output); ADC1 channel 3, Hall sensor VN.

LED_BUILTINGPIO25 Used by the white LED onboard hardware

Wired to the white LED on this board. The pin is yours if you give that up, but nothing else can share it.

A15GPIO12 Bootstrapping pin; JTAG TDI; sets flash voltage (VDD_SDIO); also HSPIQ (flash data line). Strapping

Keep LOW during boot (internal PD); pulling HIGH at reset selects 1.8V flash mode, causing flash brownout if 3.3V flash is used.

A14GPIO13 JTAG clock pin (TCK); also ADC2 channel 4 / Touch4 input. JTAG

Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed.

SDAGPIO21 Vext control: LOW turns the Vext rail on onboard hardware

Wired to the Vext power switch on this board. The pin is yours if you give that up, but nothing else can share it.

Only if you know the tricks

8 pins · 1 thing to know

MISOGPIO19SSGPIO18SCKGPIO5A6GPIO34A7GPIO35A19GPIO26MOSIGPIO27A16GPIO14 Used by the SX1276 LoRa radio onboard hardware

Wired to the SX1276 LoRa radio on this board, which is soldered down. Driving it from your own code breaks that function.

MISO
SS
SCKstrapping pin - LOW while flashing
A6input-only
A7input-only
A19
MOSI
A16

These are recommendations, not hard rules - with the right pull-ups, timing and boot-state awareness most pins can be made to work. When in doubt, start green.

The Heltec WiFi LoRa 32(V2) breaks out 36 pins in total: 28 GPIO for your project, with GND, 5V, Vext and 3V3 handling power.

Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO21 and SCL on GPIO22; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO1 and GPIO3 cover serial logging and flashing.

Beyond plain digital I/O you get 18 ADC-capable pins for sensors and battery monitoring, PWM on 2 pins, 10 capacitive-touch inputs and 2 true DAC outputs.

15 of the exposed pins carry boot-time or system duties on the ESP32 (RX, TX, KEY_BUILTIN and 12 more) - check the guidance above before wiring anything to them. SCL, GPIO23, GPIO17, A4 and 1 more are free of any such role - the safest first picks.

Getting started

flash your first firmware in ~2 minutes

Tool:

Connect over USB

Uses a CP2102 bridge - install the CP210x driver if no port appears. Not detected? Hold BOOT while plugging in.

Match & flash

Set the Tools options shown, then click Upload.

Verify it runs

GPIO22 toggles - wire an LED and resistor to it, or change the pin to your board's own LED.

Set these in Tools · leave everything else at default

Arduino IDE 2.x - Tools Copy

Board: "ESP32 Dev Module"▸

Flash Size: "8MB (64Mb)"▸

Flash Mode: "DIO"▸

Partition Scheme: "8M with spiffs (3MB APP/1.5MB SPIFFS)" (default)▸

Upload Speed: "921600"▸

▸ every other Tools option - leave at default

Board: ESP32 Dev Module
Flash Size: 8MB (64Mb)
Flash Mode: DIO
Partition Scheme: 8M with spiffs (3MB APP/1.5MB SPIFFS)
Upload Speed: 921600

Find it: Tools ▸ Board ▸ ESP32 Arduino ▸ ESP32 Dev Module

blink.ino Copy

// toggle GPIO22 - wire an LED and resistor to it
void setup() {
  pinMode(22, OUTPUT);
}
void loop() {
  digitalWrite(22, HIGH); delay(500);
  digitalWrite(22, LOW);  delay(500);
}

board to selectesp32dev⧉ copy

platformio.ini Copy

[env:heltec_wifi_lora_32_V2]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600

Find it: PlatformIO Home ▸ Boards, search esp32dev - or type it after board =.

board to selectesp32dev⧉ copy

device.yaml Copy

esp32:
  board: esp32dev
  variant: esp32
  framework:
    type: esp-idf

# blink - GPIO22
output:
  - platform: gpio
    pin: 22
    id: led_out
light:
  - platform: binary
    name: "LED"
    output: led_out

Find it: search ESPHome's board list for esp32dev (same ids as PlatformIO).

esptool doesn't pick board settings - a prebuilt .bin already has them baked in. This is just the raw flash command.

terminal Copy

esptool.py --chip esp32 --port /dev/ttyACM0 \
  --baud 921600 write_flash 0x1000 firmware.bin

--port = your /dev/tty* (macOS/Linux) or COMx (Windows).

Build details: sketch space 3342336 B · data 327680 B · DIO

Downloads

Free for non-commercial use, credit espboards.dev · License

Board illustration

The bare Heltec WiFi LoRa 32(V2) board drawn to scale at 50.2 × 25.5 mm, with no pin labels on it. Made for slide decks, wiring diagrams and project write-ups where a photo is too busy. Take the scalable SVG for print or editing, the high-resolution PNG to drop straight in, or the transparent PNG when you need it with no background behind it.

SVG - download the Heltec WiFi LoRa 32(V2) board illustration as a vector file Vector, any size · 90 KB PNG - download the Heltec WiFi LoRa 32(V2) board image, high resolution 1200 px wide · 342 KB PNG transparent - download the Heltec WiFi LoRa 32(V2) board image with no background No background · 379 KB

Pinout diagram

Every pin on both sides of the board with its functions, drawn by ESPboards from the ESP32 Series Datasheet v5.3 - the same sheet shown at the top of this page. The PNG is a high-resolution image for screens, the SVG is vector so it stays sharp at any size, and the PDF is laid out to print on A4 or Letter.

Free for non-commercial use, with the credit line kept.

Embed the Heltec WiFi LoRa 32(V2) pinout

Paste this where you want the diagram. Keep the credit line - it is what the licence asks for, and it is the only thing we want in return.

<figure>
  <img src="https://cdn.espboards.net/boards/heltec-wifi-lora-32-v2/diagram-1600.png"
       alt="Heltec WiFi LoRa 32(V2) pinout diagram" width="1600" loading="lazy">
  <figcaption>
    Heltec WiFi LoRa 32(V2) pinout by
    <a href="https://www.espboards.dev/esp32/heltec_wifi_lora_32_V2/">ESPboards</a>,
    <a href="https://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC 4.0</a>
  </figcaption>
</figure>

Using it commercially? Ask us first - it takes one email.

Yours to use, share and adapt for non-commercial work, as long as you credit espboards.dev - the full terms and ready-made credit lines are here.

Specifications

ESP32 · 50.2 × 25.5 mm · vs other ESP32 chips →

Compute

MCU

ESP32

Clock

240 MHz

SRAM · Flash

520 KB · 8MB

Radio

Wi-Fi

802.11 b/g/n

Bluetooth

4.2 LE

Antenna

PCB

I/O

GPIO · ADC

28 · 18

UART · I²C · SPI

3 · 2 · 2

PWM

16 channels

Power

USB

Micro-USB

Serial

CP2102

Boot address

0x1000

Electrical

Input

5V USB · 3.7V LiPo

Consumption

800µA sleep

Regulator

Display

Screen

OLED · 0.96" · 128x64

Driver

SSD1306

Touch

Flashing

Upload · OTA

esptool_py · esp_ota

Flash · Boot mode

DIO · QIO

Sketch · Data

3.19 MB · 320 KB

Dimensions

Heltec WiFi LoRa 32(V2) board, drawn to scale

50.2 × 25.5 mm · pin pitch 2.54 mm

The Heltec WiFi LoRa 32(V2) uses esptool_py for firmware uploads, esp_ota for over-the-air (OTA) updates. Flash mode is DIO with QIO boot mode. The maximum sketch size is 3.19 MB with 320 KB available for data.

About this board

Inside sits the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.

The $17.90 price tag is typical for an ESP32 board.

Around the module: an OLED 0.96" 128x64 display, LoRa (SX1276), battery charging via JST-SH 1.25mm and Reset/PRG buttons.

2.4GHz metal spring antenna for Wi-Fi/BT; IPEX (u.FL) connector with external antenna for LoRa
Onboard Li-Po charge/discharge management with automatic USB/battery power switching
LoRa variants ship as SX1276 (868/915MHz) or SX1278 (433MHz)

Where to buy

prices are typical street prices

Heltec WiFi LoRa 32(V2)

$17.90per unit, typical

Resources

Board datasheet resource.heltec.cn↗ ESP32 datasheet espressif.com↗ WiFi LoRa 32 (V2) - Heltec documentation docs.heltec.org↗WiFi LoRa 32 (V2) product page - Heltec heltec.org↗

Similar boards

Adafruit ESP32 Feather Feather-format ESP32 board with LiPo charging - great for wireless projects… ESP32 · 4MB

Adafruit Feather ESP32 V2 Updated Feather ESP32 with improved power handling and USB-C - great for… ESP32 · 8MB

Adafruit ItsyBitsy ESP32 Small ESP32 board in ItsyBitsy format - ideal for low-power wireless projects… ESP32 · 8MB