General Description

audio_trigger_montato_lowVirtualSense is an ultra-low power wireless node for use in wireless sensor networks (WSNs) subject to tight power constraints. Thanks to the on board Java compatible virtual machine (VM) it allows programmers to rapidly develop monitoring applications and communication protocols. VirtualSense makes use of IEEE 802.15.4 wireless transceivers in order to standardize communication and to inter-operate with other existing devices. The set of on board sensors (including pressure, temperature, and light), together with the possibility to easily connect any external sensor/actuator, allows VirtualSense to be used in a wide range of application fields.

In order to promote research and development VirtualSense is developped in a modular way and it adopts an open-hardware/open-source model. In particular, it mounts widely available off-the-shelf components and it makes publicly available all PCB schematics. The open-source software stack is based on a modified version of Darjeeling java-compatible VM running on top of Contiki operating system.


Key Components and Features

The key components of VirtualSense 1.0 are listed below:

  • 250kbps 2.4GHz IEEE 802.15.4 Texas Instruments cc2520 Wireless Transceiver
  • 25MHz Texas Instruments MSP430f54xxa microcontroller unit (MCU) with 16k RAM and 128k Flash
  • Integrated Pressure, Temperature, and Light sensors
  • 512K I2C™ Serial EEPROM
  • On-board 48-bit I2C Extended Unique Identifier (EUI-48™)
  • On-board programmable ultra-low-power RTC

The distinguishing features include:

  • Ultra low power consumption (≈0.66µW in hibernation, ≈1.5µW in sleep mode, 10/60mW in send/receive modes, respectively)
  • Compatibility with state-of-the-art energy harvesting modules
  • Fast wakeup from sleep mode (<5μs)
  • Programmable timed wake-up from any low-power mode
  • Sensitivity to asynchronous external events
  • Integrated 12-bit ADC/DAC
  • Integrated Supply Voltage Supervisor (SVS)
  • Integrated DMA Controller
  • USB 2.0 RS232/UART communication and firmware programming 
  • Interoperability with other IEEE 802.15.4 devices
  • Open-source software stack
  • Contiki MAC-layer compatibility
  • Java-compatible run-time environment
  • Easy Over the Air (OTA) programming