# Heltec LoRa Kit 151 > Ultra-low-power LoRaWAN development kit based on STM32L151CBU6 ARM Cortex-M3 MCU and Semtech SX1278 LoRa transceiver, with 6uA deep sleep current, integrated battery management, and CE certification. ## Quick Facts - **Brand:** heltec - **Price:** ~$13.5 - **Product Readiness:** production - **CPU:** ARM Cortex-M3 single-core @ 32MHz, ultra-low-power - **CPU Architecture:** ARM Cortex-M3 - **CPU Cores:** 1 - **RAM:** 16KB SRAM - **Flash:** 128KB - **USB:** Micro-USB - **Power:** 5V via Micro-USB,3.7V LiPo - **Operating Voltage:** 3.3V - **Operating Temp:** -20°C to +70°C - **Dimensions:** 56.3 x 25.5 x 7.8mm - **Weight:** 20g - **Battery:** External 3.7V LiPo (SH1.25 connector) - **Antenna:** IPEX - **SD Card:** No ## Connectivity - **Lora:** SX1278 433/470MHz,, 19dBm TX, -135dBm RX ## Certifications CE ## Use Cases - lorawan-node - environmental-monitoring - irrigation-control - smart-agriculture - asset-tracking ## Components - **STM32L151CBU6** (mcu): STMicroelectronics STM32L151CBU6 ultra-low-power 32-bit ARM Cortex-M3 MCU running at up to 32MHz with 128KB flash, 16KB SRAM, 4KB EEPROM, 12-bit ADC/DAC, and deep sleep current as low as 6uA. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.st.com%2Fresource%2Fen%2Fdatasheet%2Fstm32l151cc.pdf&ref=openhardware.directory&product=heltec-lora-kit-151&source=md-export) - **SX1278** (radio): Semtech SX1278 LoRa transceiver supporting 137-525MHz with LoRa modulation, -135dBm sensitivity at SF12/125kHz, and +19dBm maximum TX power for long-range LPWAN communication. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fcdn-shop.adafruit.com%2Fproduct-files%2F3179%2Fsx1276_77_78_79.pdf&ref=openhardware.directory&product=heltec-lora-kit-151&source=md-export) - **CP2102** (usb-uart): Silicon Labs CP2102 single-chip USB to UART bridge IC providing USB 2.0 full-speed connectivity for programming and serial debug output. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.silabs.com%2Fdocuments%2Fpublic%2Fdata-sheets%2FCP2102-9.pdf&ref=openhardware.directory&product=heltec-lora-kit-151&source=md-export) - **TP4054** (battery-charger): TP4054 single-cell lithium-ion/polymer battery charger with programmable charge current, providing integrated battery management with USB/battery automatic power switching. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.alldatasheet.com%2Fdatasheet-pdf%2Fpdf%2F1132571%2FETC2%2FTP4054.html&ref=openhardware.directory&product=heltec-lora-kit-151&source=md-export) ## Protocols - **SPI1** (SPI1): SCK: PA5, MISO: PA6, MOSI: PA7, NSS: PA4 - **SPI2** (SPI2): SCK: PB13, MISO: PB14, MOSI: PB15, NSS: PB12 - **SPI3** (SPI3): SCK: PB3, MISO: PB4, MOSI: PB5, NSS: PA15 - **I2C1** (I2C1): SCL: PB8, SDA: PB9 - **I2C2** (I2C2): SCL: PB10, SDA: PB11 - **UART1** (UART1): TX: PA9, RX: PA10 - **UART2** (UART2): TX: PA2, RX: PA3 - **UART3** (UART3): TX: PB10, RX: PB11 - **ADC** - **DAC** - **SWD**: SWDIO: PA13, SWCLK: PA14 ## GPIO Map | Pin | Name | Type | Functions | |-----|------|------|-----------| | PA0 | ADC_IN0, WKUP — Analog Input / Wake-up | ADC | digital-input, digital-output, adc, pwm | | PA1 | ADC_IN1 — Analog Input | ADC | digital-input, digital-output, adc, pwm | | PA2 | ADC_IN2, TX2 — UART2 Transmit / Analog | UART | digital-input, digital-output, adc, pwm | | PA3 | ADC_IN3, RX2 — UART2 Receive / Analog | UART | digital-input, digital-output, adc, pwm | | PA4 | LoRa_NSS, DAC_OUT1, ADC_IN4, NSS1 — LoRa Chip Select (reserved) | SPI | digital-input, digital-output, adc, dac | | PA5 | LoRa_SCK, DAC_OUT2, ADC_IN5, SCK1 — LoRa SPI Clock (reserved) | SPI | digital-input, digital-output, adc, dac | | PA6 | LoRa_MISO, ADC_IN6, MISO1 — LoRa SPI MISO (reserved) | SPI | digital-input, digital-output, adc | | PA7 | LoRa_MOSI, ADC_IN7, MOSI1 — LoRa SPI MOSI (reserved) | SPI | digital-input, digital-output, adc | | PA8 | GPIO — General Purpose I/O | — | digital-input, digital-output, pwm | | PA9 | TX1 — UART1 Transmit | UART | digital-input, digital-output, pwm | | PA10 | RX1 — UART1 Receive | UART | digital-input, digital-output, pwm | | PA13 | SWDIO — Serial Wire Debug Data | SWD | digital-input, digital-output | | PA14 | SWCLK — Serial Wire Debug Clock | SWD | digital-input, digital-output | | PA15 | NSS1/NSS3 — SPI Chip Select | SPI | digital-input, digital-output, pwm | | PB0 | LoRa_DIO3, ADC_IN8 — LoRa Interrupt (reserved) | ADC | digital-input, digital-output, adc | | PB1 | LoRa_DIO2, ADC_IN9 — LoRa Interrupt (reserved) | ADC | digital-input, digital-output, adc | | PB3 | SCK1/SCK3, Vext control — SPI Clock / External Power Control | SPI | digital-input, digital-output, pwm | | PB4 | MISO1/MISO3 — SPI MISO | SPI | digital-input, digital-output, pwm | | PB5 | MOSI3/MOSI1 — SPI MOSI | SPI | digital-input, digital-output, pwm | | PB6 | SCL1 — I2C1 Clock | I2C | digital-input, digital-output | | PB7 | SDA1 — I2C1 Data | I2C | digital-input, digital-output | | PB8 | SCL1, LED — I2C1 Clock / LED | I2C | digital-input, digital-output, pwm | | PB9 | SDA1 — I2C1 Data | I2C | digital-input, digital-output | | PB10 | SCL2, TX3 — I2C2 Clock / UART3 Transmit | I2C | digital-input, digital-output, pwm | | PB11 | SDA2, RX3, LoRa_DIO0 — I2C2 Data / UART3 RX / LoRa Interrupt (reserved) | I2C | digital-input, digital-output | | PB12 | NSS2, ADC_IN18 — SPI2 Chip Select / Analog | SPI | digital-input, digital-output, adc | | PB13 | SCK2, ADC_IN19 — SPI2 Clock / Analog | SPI | digital-input, digital-output, adc | | PB14 | MISO2, ADC_IN20 — SPI2 MISO / Analog | SPI | digital-input, digital-output, adc | | PB15 | MOSI2, ADC_IN21 — SPI2 MOSI / Analog | SPI | digital-input, digital-output, adc | ## Description ## Overview The Heltec LoRa Kit 151 is an ultra-low-power LoRaWAN development board designed for battery-powered IoT sensor node applications. Built around the STM32L151CBU6 ARM Cortex-M3 microcontroller and Semtech SX1278 LoRa transceiver, it achieves a remarkably low deep sleep current of just 6uA, making it ideal for remote field deployments where devices must operate for months or years on a single battery charge. The board comes in two frequency variants: the LoRa-Kit-151-L for 433-510MHz (EU433/CN470 bands) and the LoRa-Kit-151-F for 863-928MHz (EU868, US915, AU915, AS923, KR920 bands). Both variants support standard LoRaWAN 1.0.2 protocol with Class A, B, and C operation modes, and include AT command firmware for rapid prototyping without custom coding. With 23 exposed GPIO pins including 8 ADC channels, 2 DAC outputs, 3 UART ports, 2 SPI buses, and 2 I2C buses, the LoRa Kit 151 provides ample interfacing options for connecting environmental sensors, actuators, and other peripherals. The onboard battery management system with TP4054 charger IC, SH1.25 battery connector, and automatic USB/battery power switching makes it ready for portable and field-deployed applications right out of the box. The compact 56.3 x 25.5mm form factor with standard 2.54mm pin headers and breadboard-compatible layout makes it easy to integrate into custom PCB designs or prototype on a breadboard. An integrated CP2102 USB-to-serial bridge simplifies programming and debugging via the Micro-USB port. ## Where to Buy - [Heltec Official Store](https://openhardware.directory/r?to=https%3A%2F%2Fheltec.org%2Fproject%2Flora-kit-151%2F&ref=openhardware.directory&product=heltec-lora-kit-151&source=md-export) — 13.50 ## Resources - [product](https://openhardware.directory/r?to=https%3A%2F%2Fheltec.org%2Fproject%2Flora-kit-151%2F&ref=openhardware.directory&product=heltec-lora-kit-151&source=md-export) - [datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fresource.heltec.cn%2Fdownload%2FLoRa_Kit_151%2Fkit151.pdf&ref=openhardware.directory&product=heltec-lora-kit-151&source=md-export) - [schematics](https://openhardware.directory/r?to=https%3A%2F%2Fresource.heltec.cn%2Fdownload%2FLoRa_Kit_151%2FLoRa_Kit_151_sch_diagram.PDF&ref=openhardware.directory&product=heltec-lora-kit-151&source=md-export) - [github](https://openhardware.directory/r?to=https%3A%2F%2Fgithub.com%2FHelTecAutomation&ref=openhardware.directory&product=heltec-lora-kit-151&source=md-export) - [wiki](https://openhardware.directory/r?to=https%3A%2F%2Fdocs.heltec.org%2Fen%2Fnode%2Fstm32%2Flora_node_151%2Findex.html&ref=openhardware.directory&product=heltec-lora-kit-151&source=md-export) ## Tags `lora`, `lorawan`, `stm32`, `low-power`, `iot`, `sensor-node`, `battery-powered` ## Images ![Heltec LoRa Kit 151](https://nbg1.your-objectstorage.com/openhardware-directory/entities/heltec-lora-kit-151/76f912ade0cb.png) ![Heltec LoRa Kit 151](https://nbg1.your-objectstorage.com/openhardware-directory/entities/heltec-lora-kit-151/f2e35eaeb93d.jpg) ![Heltec LoRa Kit 151](https://nbg1.your-objectstorage.com/openhardware-directory/entities/heltec-lora-kit-151/fa224d08de45.png) > **Battery Powered:** lithium-battery --- [View full device page](https://openhardware.directory/devices/heltec-lora-kit-151)