Low-power, low-cost Wi-Fi modules have changed the landscape of wireless sensor networks. Autonomous Wi-Fi sensors can connect to common, widely available wireless network infrastructure. They send sensor data over standard TCP/IP, making their information available anywhere in the world from any computer or smartphone.

Previously, wireless sensors networks were built on top of proprietary protocols running on sub-GHz radios. These systems have the benefit of covering long distances however they are closed systems. Likewise, sensors networks based Zigbee^® radios are also closed systems. Both types of wireless sensor networks require additional gateway hardware devices to get sensor data onto the Internet or the user's LAN. Gateways introduce a single point of failure and additional costs.

Built on standard 802.11 b/g Wi-Fi infrastructure, remote sensor networks contain three main components: battery-powered sensors, standard Wi-Fi access points, and server software that receives, stores and presents sensor data. Sensor information can be viewed from a device on the network or, if desired, from any Internet-accessible location. If the sensor is not in range of the Wi-Fi access point, additional access points can be added as repeaters. The sensor only needs to know the SSID and passphrase to join the network, and with the preprogrammed IP or URL address, the sensor can start sending data to the server.

The sensor can intelligently send data to the server based on a time period, sensor event or even if the data meets a programmed criteria. These capabilities can be controlled from the server by provisioning the sensor when it first connects. If the network goes down or the sensor goes out of range, data is cached on the sensor. When the network comes back up, the sensor can catch up with the server.