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Heltec WiFi LoRa 32 V3

Device Type:misc
Electrical Standard:Global
Board:esp32

Heltec WiFi LoRa 32 V3

Model reference: WiFi LoRa 32 V3

Manufacturer: Heltec Automation

Product Description

The Heltec WiFi LoRa 32 V3 is a development board featuring an ESP32-S3 microcontroller with integrated WiFi, Bluetooth, and a Semtech SX1262 LoRa radio transceiver. It includes a 0.96” OLED display and is designed for IoT applications requiring long-range wireless communication.

Key Features

  • ESP32-S3 dual-core processor @ 240MHz
  • 8MB Flash memory
  • SX1262 LoRa radio (433MHz or 868/915MHz variants)
  • 0.96” OLED display (128x64)
  • WiFi 802.11 b/g/n
  • Bluetooth 5 (LE)
  • USB-C connector
  • LiPo battery connector with charging circuit
  • Onboard CP2102 USB-to-UART bridge

GPIO Pinout

LoRa SX1262 Pins

FunctionGPIO
SPI CLKGPIO9
SPI MOSIGPIO10
SPI MISOGPIO11
CSGPIO8
RSTGPIO12
BUSYGPIO13
DIO1GPIO14

Display (OLED)

FunctionGPIO
SDAGPIO17
SCLGPIO18
RSTGPIO21

Other Pins

FunctionGPIO
ButtonGPIO0
LEDGPIO35
Battery ADCGPIO1
Vext ControlGPIO36

Basic Configuration

Minimum configuration required for the Heltec WiFi LoRa 32 V3:

esphome:
  name: "heltec"


esp32:
  variant: esp32s3
  flash_size: 8MB
  cpu_frequency: 240MHZ
  framework:
    type: esp-idf


logger:
  hardware_uart: UART0


api:


ota:
  platform: esphome


wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password


# SPI bus for LoRa radio
spi:
  clk_pin: GPIO9
  mosi_pin: GPIO10
  miso_pin: GPIO11


# I2C for OLED display
i2c:
  sda: GPIO17
  scl: GPIO18
  frequency: 400kHz

LoRa Radio Configuration

# LoRa Radio Configuration (SX1262)
sx126x:
  dio1_pin: GPIO14
  cs_pin: GPIO8
  busy_pin: GPIO13
  rst_pin: GPIO12
  pa_power: 3
  bandwidth: 125_0kHz
  crc_enable: true
  frequency: 433920000
  modulation: LORA
  rx_start: true
  hw_version: sx1262
  rf_switch: true
  sync_value: [0x14, 0x24]
  preamble_size: 8
  spreading_factor: 7
  coding_rate: CR_4_6
  tcxo_voltage: 1_8V
  tcxo_delay: 5ms
  on_packet:
    - lambda: |-
        ESP_LOGD("lora", "Received packet RSSI: %.2f dBm, SNR: %.2f dB, Data: %s",
                 rssi, snr, format_hex(x).c_str());


# Example button to send LoRa packet
button:
  - platform: template
    name: "Send LoRa Packet"
    on_press:
      then:
        - sx126x.send_packet:
            data: [0xDE, 0xAD, 0xBE, 0xEF, 0xCA, 0xFE, 0xBA, 0xBE]

FSK Modulation Configuration

# FSK Radio Configuration (SX1262)
sx126x:
  dio1_pin: GPIO14
  cs_pin: GPIO8
  busy_pin: GPIO13
  rst_pin: GPIO12
  pa_power: 3
  bandwidth: 78_2kHz
  crc_enable: true
  frequency: 433920000
  modulation: FSK
  rx_start: true
  payload_length: 0
  hw_version: sx1262
  bitrate: 4800
  rf_switch: true
  sync_value: [0x33, 0x33]
  preamble_size: 4
  preamble_detect: 2
  tcxo_voltage: 1_8V
  tcxo_delay: 5ms
  on_packet:
    then:
      - lambda: |-
          ESP_LOGD("fsk", "Packet RSSI: %.2f dBm, SNR: %.2f dB, Data: %s",
                   rssi, snr, format_hex(x).c_str());


button:
  - platform: template
    name: "Send FSK Packet"
    on_press:
      then:
        - sx126x.send_packet:
            data: [0xC5, 0x51, 0x78, 0x82, 0xB7, 0xF9, 0x9C, 0x5C]

OLED Display Configuration

Configuration to use the onboard 0.96” OLED display:

# OLED Display
display:
  - platform: ssd1306_i2c
    model: "SSD1306 128x64"
    reset_pin: GPIO21
    address: 0x3C
    lambda: |-
      it.printf(0, 0, id(font), "Heltec V3");
      it.printf(0, 16, id(font), "WiFi LoRa 32");
      it.printf(0, 32, id(font), "%.1f dBm", id(wifi_signal_db).state);


font:
  - file: "gfonts://Roboto"
    id: font
    size: 14


sensor:
  - platform: wifi_signal
    id: wifi_signal_db
    name: "WiFi Signal"
    update_interval: 60s

Battery Monitoring

Configuration to monitor LiPo battery voltage:

sensor:
  - platform: adc
    pin: GPIO1
    name: "Battery Voltage"
    attenuation: 12db
    filters:
      - multiply: 2.0  # Voltage divider correction
    update_interval: 60s

Power Management

The Vext pin (GPIO36) controls power to external peripherals. Set it LOW to enable power:

switch:
  - platform: gpio
    pin: GPIO36
    id: vext
    name: "Vext Control"
    inverted: true
    restore_mode: ALWAYS_ON