The improvement in chip manufacturing and new low-power wireless standards is enabling what are called Wireless Sensor Networks (WSN). These networks consist of tiny nodes, equipped with a microprocessor and sensors, wirelessly connected in a mesh network to exchange information and trigger actions.
WSNs can enable a wide range of applications related with supervision, control and tracking in areas such as military, medical, industrial, security, traffic or home and office automation.
The nodes are specified to have very small dimensions, low power consumption, limited processing and memory, low data-rate wireless transmission and able to support extreme environmental conditions. This autonomy provides the flexibility to deploy the nodes virtually anywhere without need for any wiring, as nodes can be battery or solar powered. Being connected in a wireless mesh network also guarantees extra resilience if a sensor node fails.
ZigBee is one of the most successful open standards developed around the IEEE 802.15.4 spec, and designed to meet the requirements of:
- low cost
- ultra-low power consumption
- use of unlicensed radio bands with low data-rates
- cheap and easy installation
- flexible and extendable networks
- integrated intelligence for network set-up and message routing
A ZigBee tutorial can be found here. There are different software and hardware platforms to implement WSN nodes.
- TinyOS is an open embedded OS for WSN, written in nesC, a dialect of C
- Sun SPOT is a device with a 180MHz ARM core and 512KB RAM, and supporting different sensors (light, temperature, accelerometer and analog inputs). Sun SPOT is built on the Squawk Virtual Machine
WSNs is still an emerging topic but it surely represents an important opportunity for entrepreneurs to create innovative applications. Mobile Operators will also show a lot of interest as many WSNs will be back-hauled by a gateway connected to the mobile network, multiplying the machine-to-machine traffic as more an more Wireless Sensor Networks invade our homes, offices and cars.