Adafruit Feather M0 with LoRa Radio (with hands-on example)
- 1. Adafruit Feather M0 with LoRa Radio Claudio Pastorini Hands-on example for the Pervasive Systems course A.A. 2017/2018 University of Rome La Sapienza
- 2. Adafruit Feather M0 Radio with LoRa Radio Module : Board/Processor ATSAMD21G18 (32-bit ARM Cortex M0+) @ 48MHz with 3.3V logic/power Embedded with lithium battery management chip and status indicator led 20 GPIOs (All pins but only 8 are PWM) 1 x analog output (10-bit DAC) 10 x analog inputs (12-bit ADC) 3 x pins for RFM/SemTech control 3.3V regulator with 500mA output Flash Memory : 256 kb SRAM : 32 kb Reset button 1 x pin for antenna (no built-in antenna)
- 3. Adafruit Feather M0 Radio with LoRa Radio Module : Board/Modules RFM9x LoRa 868/915 MHz radio module embedded by SX1276 transceiver. High link budget of 160dB. -140dBm sensitivity and 19dBm Output power. Support Class A/C LoRaWAN protocol 1.45uA sleep current in WOR mode Dual band: 19dBm@434MHz/470MHz 14dBm@868MHz/915MHz
- 4. ATSAMD21G18 : Block Diagram
- 5. RFM9x LoRa : Block Diagram
- 6. SX1276 : Block Diagram
- 7. LoRa : Frequency regulation LoRa supports a wide range of license free frequency bands Every State has its own unlicensed bands but each one can add other constraints (such as power use, time of transmission and so on) In Italy (and Europe) we can use the 434 MHz and 868 MHz frequency bands
- 8. Adafruit Feather M0 Radio with LoRa Radio Module : Antenna No internal antenna In order to achive long distance we need one based on the frequency used 433 MHz - 6.5 inches, or 16.5 cm 868 MHz - 3.25 inches or 8.2 cm 915 MHz - 3 inches or 7.8 cm
- 10. SX1276 : Modem behaviour
- 11. LoRa: Packet structure The LoRa modem employs two types of packet format, explicit and implicit. The explicit packet includes a short header that contains information about the number of bytes, coding rate and whether a CRC is used in the packet.
- 12. SX1276 : Driver In order to use the RFM9x radio module with SX1276 we need a driver. This is the RadioHead Packet Radio library for embedded microprocessors. It provides a complete object-oriented library for sending and receiving packetized messages via a variety of common data radios and other transports on a range of embedded microprocessors. http://www.airspayce.com/mikem/arduino/RadioHead/
- 13. Hands-on example The example is a simple Ping Pong application with two different LoRa boards communicate each other. One board is the Adafruit Feather M0 with LoRa Radio module the other one is the Seeduino LoRaWAN. Both boards use the same Arduino sketch, the first using the RadioHead Driver, the other one instead use AT commands over serial communication. https://github.com/claudiopastorini/PingPong