What is the LSN50

LSN50 is a Long Range LoRa Sensor Node. It is designed for outdoor use and powered by Li/SOCl2 battery for long term use power consumption and secure data transmission.It is designed to facilitate developers to quickly deploy industrial level LoRa and IoT solutions. It help users to turn the idea into a practical application and make the Internet of Things a reality. It is easy to program, create and connect your things everywhere.

It is based on SX1276/SX1278 allows the user to send data and reach extremely long ranges at low data-rates.It provides ultra-long range spread spectrum communication and high interference immunity whilst minimising current consumption.It targets professional wireless sensor network applications such as irrigation systems, smart metering, smart cities, smartphone detection, building automation, and so on.

LSN50 uses STM32l0x chip from ST, STML0x is the ultra-low-power STM32L072xx microcontrollers incorporate the connectivity power of the universal serial bus (USB 2.0 crystal-less) with the high-performance ARM® Cortex®-M0+ 32-bit RISC core operating at a 32 MHz frequency, a memory protection unit (MPU), high-speed embedded memories (192 Kbytes of Flash program memory, 6 Kbytes of data EEPROM and 20 Kbytes of RAM) plus an extensive range of enhanced I/Os and peripherals.

LSN50 is an open source product, it is based on the STM32Cube HAL drivers and lots of libraries can be found in ST site for rapid development.

STM32l0x

• The maximum link budget is 157 dB
• +20 dBm, 100 mW constant RF output with Vsupply
• +14 dBm high efficiency PA
• Programmable bit rates up to 300 k
• High sensitivity: down to -137 dBm
• Bulletproof front end: IIP3 = -12.5 dBm
• 89 dB blocking immunity
• The low RX current is 10 mA and the register is held at 200 nA
• Fully integrated synthesizer with 61 Hz resolution
• FSK, GFSK, MSK, GMSK, LoRa and OOK modulations
• Bit built-in synchronizer for clock recovery
• Synchronous word recognition
• Preamble detection
• 127 dB + dynamic range RSSI
• Built-in temperature sensor and low battery indicator 1.65 V to 3.6 V power supply

Specifications

MCU Side:

• MCU: STM32L072CZT6
• Flash:192KB
• RAM:20KB
• EEPROM: 6KB
• Clock Speed: 32Mhz

LoRa Side:

• LoRa Chip: sx1276/sx1278
• 68 dB maximum link budget.
• +20 dBm – 100 mW constant RF output vs.
• +14 dBm high efficiency PA.
• Programmable bit rate up to 300 kbps.
• High sensitivity: down to -148 dBm.
• Bullet-proof front end: IIP3 = -12.5 dBm.
• 127 dB Dynamic Range RSSI.
• LoRaWAN 1.0.2 Specification

Absolute Maximum Ratings:

• I/O pins: 0.5v ~ VCC+0.5V

Common DC Characteristics:

• Supply Voltage: 2.1v ~ 3.6v
• Operating Tempature: -40 ~ 85°C
• I/O pins: Refer to STM32L072 datasheet

Power Consumption:

• STOP Mode: 2.7uA @ 3.3v
• LoRa Transmit Mode:

125mA @ 20dBm 44mA @ 14dBm

Battery:

• Li/SOCI2 unchargable battery
• Capacity: 4000mAh
• Self Discharge: <1% / Year @ 25°C
• Max continuously current: 130mA
• Max boost current: 2A, 1 second

Dimensions:

• Size:65 x 50 x 50mm
• Net Weight: 140g

Features

• STM32L072CZT6 MCU
• SX1276/78 Wireless Chip
• Pre-load bootloader on USART1/USART2
• MDK-ARM Version 5.24a IDE
• I2C,LPUSART1,USB
• 2x12bit ADC, 1x12bit DAC
• 18xDigital I/Os
• LoRa™ Modem
• Preamble detection
• Baud rate configurable
• CN470/EU433/KR920/US915
• EU868/AS923/AU915
• Open source hardware / software
• Available Band:433/868/915/920 Mhz
• IP66 Waterproof Enclosure
• Ultra Low Power consumption
• AT Commands to change parameters
• 4000mAh Battery for long term use

Applications

• Wireless Alarm and Security Systems
• Home and Building Automation
• Automated Meter Reading
• Industrial Monitoring and Control
• Long range Irrigation Systems,etc.

Getting Start

Power On/Off the LSN50

The LSN50 is power off before shipping to avoid accident during shipping. We use a jumper to power on/off the LSN50, This will be useful for monitoring power consumption when connecting to different sensors and with different software. User can power on the device by simply adding the jumper to the board , as below.

Use the AT Command

• 

• steps

1. 

2. 

3. 

   Open application Seral port and click Start

4. 

   You can see the status of the interface(If it does not appear, press the reset button or the AT command: ATZ.)

5. 

   Input commands: Ex)AT+ADR=0（Adaptive rate is off）.If your AT command is sent successfully, the software will receive feedback (OK).

• Tips:If you want to know the more commands,you can send: AT+?.)

Program LSN50

• Download Flashloader(Here is just sample application.You can also use the same type of programming application.And the method is similar.) and download STM32CubeExpansion_LRWAN.zip(Include source code).

Steps

• Please follow the below of examples:

Result

Current consumption test in “Stop mode” mode

• Remove the jumper from JP2, connect with a multimeter, and hit 20uA.

Pin Definition

 

Case Study 1: With Oil Sensor

Schematic

• The Oil Sensor is a sliding variable resistance, floating through the float above the circuit to change the size of the resistance.

Connection steps

Calculation method

• Only for our LSN50 such as:

(TTN) The value of the first two above is 00 00, which is 0
H = 0 * 3.0 * 1000 / (3.0 * 4095) (mm)
If (TTN) data = 00 10 is 16
H = 16 * 3.0 * 1000 / (3.0 * 4095) (mm)

Case Study 2: With DS18B20 Temperature Sensor

Schematic

• DS18B20 Temperature range is -55~125℃.

The delay time when the temperature changes is 750ms.Temperature measurement error is 0.5 ℃. The programmable resolution is 9~12 bits.

Connection steps

Calculation method

• The DS18B20 is configured as 12 bits at factory shipment. When reading the temperature, a total of 16 bits are read. The first 5 bits are sign bits. When the current 5 bits are 1, the read temperature is negative. When the current 5 bits are 0, Take the temperature is positive. When the temperature is positive read method: the hexadecimal number can be converted into decimal. When the temperature is negative, the reading method is: add 1 after the hexadecimal inversion, and then convert it to 10 hexadecimal. Example: 0550H = +85 degrees, FC90H = -55 degrees.

Order Infomation

Order Info- LSN50-XX-YY

XX:

• 433: Best Tuned at 433Mhz
• 868: Best Tuned at 868Mhz
• 915: Best Tuned at 915/920 Mhz

YY:

• 12: With M12 waterproof cable hole
• 16: With M16 waterproof cable hole
• 20: With M20 waterproof cable hole