Hardware
Hardware has been developed in conjunction to the EECS (Embedded Electronics and Computing System) research group of Dipartimento di Ingegneria Industriale (University of Trento).
The network nodes - produced by Tretec S.r.l. and commercialized with the name of 3MATE! - comply with the standard IEEE 802.15.4.
The nodes computation capability is guaranteed by the 16bit Texas Instruments' MSP430F1611/8 microcontroller, whilst wireless connectivity is provided by the T.I. CC2420 radio chip. Both chips are characterized by low power consumption.
An external Flash or FRAM memory on 3MATE! device allows storing non volatile data and firmware images.
3MATE! supports TinyOS (the most widely used wireless sensor network operating system) and all the related device library.
In the snapshot a 3MATE! device is presented with highlights on main components and connections.
Main features of 3MATE! nodes
16 bit Texas Instruments microcontroller, model MSP430F1611
- RISC architecture
- 10 KB of RAM memory
- 48 KB of flash memory
- 48 I/O lines
- 12 bit analogic to digital converter with internal reference voltage
- 2 internal timer
- low power consumption
Chipcon CC2420 radio chip
- 250 Kbps
- frequency: 2.4 Ghz
- standard IEEE 802.15.4 compliant
- controllable with SPI
- adjustable output power
- low power consumption
- provide an index of the received signal strength (RSSI)
- for every received packet provide an index of the link quality (LQI)
Interfaces
- 2 USART interfaces for programming and data excange
- JTAG interface
- 3 expansion connectors (JP1, JP2 e JP6 in the picture) for daughter boards (interfaces like USB, GPRS, Ethernet and WiFi)
- 1 reset bottom
- 1 user configurable bottom
- 3 led: amber, red and green
Antenna
- Inner microstrip antenna (reversed F type): 50 m indoor range and about 125 m outdoors
- optional SMA connector to connect an external antenna (when an external antenna is used, the internal one must be disabled).
Memory
- 1 Mbyte of external flash memory (external at the microcontroller)
- SPI communication with the external flash
Sensor interface
3MATE! nodes are easily expandable by three external connectors. Through them it's possible to connect external sensor modules.
Sensors types depend on the application: custom modules can be designed by Tretec for different application fields.
Some examples are:
Building and structural monitoring
see Torre Aquila deployment
- temperature
- air humidity
- strain
- vibrations
Other features
Processing
- 16-bit MSP430F1611 RISC Architecture, 125[ns] Instruction Cycle Time
- 10 KB RAM, 48 KB Flash
- 48 General Purpose I/O lines
- 2 internal timers (with 3 and/or 7 Capture / Compare registers) and Watchdog
- Integrated Temperature and Voltage sensors
- 12-Bit A/D Converter with Internal Reference, Sample-and-Hold
Network communication
- 250kbps 2.4GHz CC2420 RF transceiver
- IEEE 802.15.4 DSSS baseband communication
- On-chip VCO, LNA and PA
- two separate tx and rx 128 byte FIFOs
- On-chip Synchronization, RSSI detection, CRC-16 and encryption capabilities
- Integrated onboard antenna with 50m range indoors and 125m range outdoors
- Optional external antenna connector
Interfaces
- 2 USART interfaces for programming and data exchange (also I2C capability)
- JTAG capabilities
- 3 expansion connectors for daughter board (for interfaces like USB, GPRS, Ethernet and WiFi)
- 1 reset button, 1 user button and 3 LEDs for direct application control