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
| Function | GPIO |
|---|---|
| SPI CLK | GPIO9 |
| SPI MOSI | GPIO10 |
| SPI MISO | GPIO11 |
| CS | GPIO8 |
| RST | GPIO12 |
| BUSY | GPIO13 |
| DIO1 | GPIO14 |
Display (OLED)
| Function | GPIO |
|---|---|
| SDA | GPIO17 |
| SCL | GPIO18 |
| RST | GPIO21 |
Other Pins
| Function | GPIO |
|---|---|
| Button | GPIO0 |
| LED | GPIO35 |
| Battery ADC | GPIO1 |
| Vext Control | GPIO36 |
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