# Heltec Turtle Board > Ultra-low-power LoRa development board with STM32L432KC ARM Cortex-M4 MCU and SX1276 transceiver, capable of 10-year battery life on AAA cells using the RadioShuttle peer-to-peer protocol. ## Quick Facts - **Brand:** Heltec Automation - **Price:** ~$41 - **CPU:** ARM Cortex-M4F single-core @ 80MHz, FPU, DSP, AES-256 hardware crypto - **CPU Architecture:** ARM Cortex-M4F - **CPU Cores:** 1 - **RAM:** 64KB SRAM - **Flash:** 256KB - **USB:** Micro-USB (DFU) - **Power:** Micro-USB,2x AAA batteries (3V),VIN 3.4-5V - **Operating Voltage:** 3.3V - **Operating Temp:** -20°C to +70°C - **Dimensions:** 73.5 x 31.5 x 24mm - **Weight:** 40g - **Antenna:** SMA,IPEX - **SD Card:** No ## Connectivity - **Lora:** SX1276 433/868/915MHz ## Certifications CE ## Use Cases - lora-sensor-node - environmental-monitoring - battery-powered-sensor - mqtt-gateway - asset-tracking ## Components - **STM32L432KC** (mcu): STMicroelectronics 32-bit ARM Cortex-M4 with FPU running at up to 80 MHz, featuring 256KB flash, 64KB SRAM, hardware AES-256 encryption, and 4 uA deep sleep current. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.st.com%2Fresource%2Fen%2Fdatasheet%2Fstm32l432kc.pdf&ref=openhardware.directory&product=heltec-turtle-board&source=md-export) - **SX1276** (radio): Semtech SX1276 LoRa transceiver supporting 137-1020 MHz with up to +20 dBm TX power, -148 dBm sensitivity, and LoRa/FSK/OOK modulation. Provides 200m to 20km range in ISM bands. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fcdn.sparkfun.com%2Fassets%2F7%2F7%2F3%2F2%2F2%2FSX1276_Datasheet.pdf&ref=openhardware.directory&product=heltec-turtle-board&source=md-export) ## Protocols - **SPI** (SPI1): MOSI: PA7, MISO: PA6, SCK: PA5, CS: PA4 - **I2C** (I2C1): SCL: PA9, SDA: PA10 - **UART** (USART2): TX: PA2, RX: PA15 - **ADC** - **DAC** - **DFU** - **SAI** ## GPIO Map | Pin | Name | Type | Functions | |-----|------|------|-----------| | PA0 | LoRa DIO0 — RX/TX Interrupt | LoRa | digital-input | | PA1 | LoRa Reset | LoRa | digital-output | | PA2 | USART2 TX (Debug Console) | UART | digital-input, digital-output, pwm | | PA3 | VEXT Power Switch | — | digital-output | | PA4 | LoRa SPI CS | SPI | digital-input, digital-output | | PA5 | SPI1 SCK (LoRa) | SPI | digital-input, digital-output | | PA6 | SPI1 MISO (LoRa) | SPI | digital-input, digital-output, adc | | PA7 | SPI1 MOSI (LoRa) | SPI | digital-input, digital-output, adc | | PA8 | Battery Power Detect | — | digital-input | | PA9 | I2C1 SCL (10k pullup) | I2C | digital-input, digital-output, pwm | | PA10 | I2C1 SDA (10k pullup) | I2C | digital-input, digital-output, pwm | | PA13 | SWDIO (Debug) | SWD | digital-input, digital-output | | PA14 | SWCLK (Debug) | SWD | digital-input, digital-output | | PA15 | USART2 RX (Debug Console) | UART | digital-input, digital-output, pwm | | PB0 | Red LED (Receive Indicator) | — | digital-output, pwm, adc | | PB1 | Green LED (Status) | — | digital-output, pwm, adc | | PB3 | SWO Debug / General GPIO | — | digital-input, digital-output, pwm | | PB4 | General Purpose GPIO | — | digital-input, digital-output, pwm | | PB5 | General Purpose GPIO | — | digital-input, digital-output, pwm | | PB6 | General Purpose GPIO | — | digital-input, digital-output, pwm | | PB7 | General Purpose GPIO | — | digital-input, digital-output, pwm | | PH3 | User Button / Boot Pin | — | digital-input | ## Description ## Overview The Heltec Turtle Board is an ultra-low-power LoRa development board designed for long-life battery-powered IoT applications. Built around the STM32L432KC ARM Cortex-M4 MCU and Semtech SX1276 LoRa transceiver, it achieves a remarkable 4 uA sleep current that enables up to 10 years of operation on two standard AAA batteries. What sets the Turtle Board apart from typical LoRa nodes is its included RadioShuttle peer-to-peer protocol software, which enables direct node-to-node communication without requiring LoRaWAN gateways or network servers. This makes it a turnkey solution for deploying wireless sensor networks in remote locations. The board also supports standard LoRaWAN protocol with AT command interface for integration into existing networks. The board exposes 18 GPIO pins through two 14-pin headers, providing access to SPI, I2C, UART, ADC, and DAC interfaces for connecting external sensors and peripherals. An optional Si7021 temperature/humidity sensor can be plugged directly onto the debug header, and I2C-compatible OLED displays (SSD1306) are supported out of the box. The integrated MQTT gateway functionality allows the board to bridge LoRa sensor data directly to cloud platforms. Programming is supported via ARM Mbed IDE and STM32CubeIDE, with firmware upload possible through DFU over USB or ST-LINK debugger. The board features automatic USB/battery power switching with ESD and short-circuit protection on the Micro-USB port. ## Where to Buy - [Heltec Store](https://openhardware.directory/r?to=https%3A%2F%2Fheltec.org%2Fproject%2Fturtle-board%2F&ref=openhardware.directory&product=heltec-turtle-board&source=md-export) — 41.00 - [AliExpress](https://openhardware.directory/r?to=https%3A%2F%2Fwww.aliexpress.com%2Fitem%2F33023966198.html&ref=openhardware.directory&product=heltec-turtle-board&source=md-export) — 29.99 - [Amazon US](https://openhardware.directory/r?to=https%3A%2F%2Fwww.amazon.com%2FHeltec-Turtle-Development-LoRaWAN-RadioShuttle%2Fdp%2FB07WPYW35M&ref=openhardware.directory&product=heltec-turtle-board&source=md-export) — 41.00 ## Resources - [product](https://openhardware.directory/r?to=https%3A%2F%2Fheltec.org%2Fproject%2Fturtle-board%2F&ref=openhardware.directory&product=heltec-turtle-board&source=md-export) - [github](https://openhardware.directory/r?to=https%3A%2F%2Fgithub.com%2FRadioShuttle%2FMBED_Turtle_RadioShuttle&ref=openhardware.directory&product=heltec-turtle-board&source=md-export) - [wiki](https://openhardware.directory/r?to=https%3A%2F%2Fdocs.heltec.cn%2Fen%2Fnode%2Fstm32%2Fturtle_board%2Findex.html&ref=openhardware.directory&product=heltec-turtle-board&source=md-export) - [datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fresource.heltec.cn%2Fdownload%2FTurtleBoard%2FTurtle%2520Board.pdf&ref=openhardware.directory&product=heltec-turtle-board&source=md-export) - [schematics](https://openhardware.directory/r?to=https%3A%2F%2Fresource.heltec.cn%2Fdownload%2FTurtleBoard%2FTurtle_Board_Pinout.pdf&ref=openhardware.directory&product=heltec-turtle-board&source=md-export) ## Tags `lora`, `stm32`, `low-power`, `iot`, `radioshuttle`, `lorawan`, `sensor-node` ## Images ![Heltec Turtle Board](https://nbg1.your-objectstorage.com/openhardware-directory/entities/heltec-turtle-board/6c6bc34f38a2.png) ![Heltec Turtle Board](https://nbg1.your-objectstorage.com/openhardware-directory/entities/heltec-turtle-board/64b316112842.png) ![Heltec Turtle Board](https://nbg1.your-objectstorage.com/openhardware-directory/entities/heltec-turtle-board/09bd98dd4020.png) ![Heltec Turtle Board](https://nbg1.your-objectstorage.com/openhardware-directory/entities/heltec-turtle-board/0ec5bd5f0ccf.png) ![Heltec Turtle Board](https://nbg1.your-objectstorage.com/openhardware-directory/entities/heltec-turtle-board/de914cb0a0fd.png) ![Heltec Turtle Board](https://nbg1.your-objectstorage.com/openhardware-directory/entities/heltec-turtle-board/72a44296dc46.png) > **Battery Powered:** yes --- [View full device page](https://openhardware.directory/devices/heltec-turtle-board)