The WSN1120L is a low profile low power WiSense Sub 1-GHz wireless mesh node. It includes the CC1120 high performance sub-ghz radio (from TI) and the MSP430G2955 microcontroller (from TI). The WiSense wireless mesh network operates in the 865-867 MHz license free band in India. The module consists of two PCBs. One PCB hosts the microcontroller while the other hosts the CC1120 radio.
Microcontroller PCB: ● MSP430G2955 ○ Ultra low power microcontroller from TI ○ 56 KB flash, 4KB SRAM ○ Standby current (in LPM3) as low as 1 micro amp. ○ Operating voltage: 1.8 V – 3.6 V ○ Multiple On-chip 10 bit ADC channels ○ Peripheral support (in hw): ■ SPI/I2C/UART ■ I2C and 1-wire (software) ■ UART/SPI (hardware) ○ On chip power supply voltage measurement ○ On chip temperature sensor ○ 2 pin Spy-Bi-Wire protocol for development (Programming and debugging). ● SPI/GPIO interface to the radio module ● UART/I2C/SPI/1-wire/GPIO interface to sensors ● On board serial (I2C) EEPROM (AT24MAC602) with hardwired and globally unique 48 bit and 64 bit addresses. ● On board 128 Kilo-Bytes EEPROM (M24M01) for over the air firmware upgrade. EEPROM can store two full images. ● On board high accuracy 32 kHz crystal ● 1 three pin right angled header (UART) – Tx, Rx and Gnd ● 1 four pin right angled header (Spy-Bi-Wire) – Vcc, Gnd, Test, Reset ● 2 LEDs ● 2 2x7 headers which expose most of the MSP430G2955 pins. ● Dimensions: 42 mm x 42 mm
Radio PCB: ● CC1120 ○ Low-cost sub-1 GHz transceiver designed for narrow band and very low-power wireless applications. Narrow band operation provides the link budget required to operate long range links (1 KM and above). ○ Programmed by WiSense stack to operate in the 865-867 MHz license free band in India. ○ Operating voltage: 2.0 V – 3.6 V ○ Sensitivity: -123 dBm @ 1.2 kBaud (865-867 MHz) ○ Modulation: 2-FSK, 4-FSK, GFSK, and MSK supported as well as OOK and flexible ASK shaping. Programmed modulation is 2-GFSK. ○ Programmable output power up to +13 dBm for all supported frequencies ○ Programmable data rate from 0 to 200 kbps. Lower the programmed data rate, higher the range. Programmed baud rate is 20 kbps. ●
● ● ●
Two antenna options (mutually exclusive) ○ U.FL antenna connector. Can use U.FL to SMA cable assembly to connect to antenna outside weatherproof enclosure. ○ PCB antenna. On board high accuracy 32 MHz crystal Uses 2 1x7 2.54 mm pitch headers for mating with microcontroller board. Dimensions: 37.61 mm x 37.61 mm
Range ● Line of Sight: More than 1000 meters @ 1.2 kbps ● Non Line of Sight: More than 500 meters @ 1.2 kbps
Power supply consideration ● ● ●
The WSN1120L supply voltage range: 1.8 V to 3.6 V Note: Exceeding 3.6 V can damage the WSN1120L !!! The WSN1120L can be powered by a 3 V lithium coin cell or a pair 1.5 V AA/AAA batteries in series. Note that the WSN1120L does not have a battery / coin cell holder. This needs to be purchased separately. Optional Solar + Li-Ion battery power supply unit (PSU).
The WSN1120L comes pre-programmed out of the box to operate as a WiSense mesh network reduced function device (RFD) in the 865-867 MHz license free band (in India). Once the node joins a WiSense mesh network, it will periodically (every 3 seconds) report the supply voltage.