Low Power Wireless Sensor Network

A group of spatially distributed, independent devices that collect data by measuring physical or environmental conditions with minimal power consumption.

A wireless sensor network (WSN) is a group of spatially distributed, independent devices that collect data by measuring physical or environmental conditions. Some of the conditions being measured are: temperature, pressure, moisture, position, usage information, lighting, and sound. Traditionally, these WSNs tend to need a lot of power to function, but decreasing the power needs of the system increases the lifetime of the sensor devices, and creates space for battery-powered applications. Battery-powered devices allow for wide-ranging use cases and opens opportunities for lower-ROI applications. This is where low power wireless sensor networks come in. The key to achieving a longer lifetime for WSN is to design wireless sensor networks that minimize power consumption of wireless sensor devices, hence the name “low power.” To cut down on overall power consumption, low power wireless sensor networks control the active time or “awake time” of the devices (such as a radio or microcontroller) and limit the current draw when they are “sleeping.” These networks accomplish this by varying the power setting modes of the devices, such as “always on”, “standby”, or “hibernation” modes. For example, think about a basic remote temperature sensor that collects data over a long period of time. In “active” mode, the device uses power to take temperature readings and to manipulate data using a sophisticated noise-filtering algorithm, but the device does not have to do this constantly. When not in active mode, the microcontroller can return to sleep mode until more sample measurements are taken. Then, at regular intervals, the Real-Time Clock and Calendar (RTCC) will wake up from sleep mode to see if there is another task to perform. If not, it will go back to sleep, conserving power usage. When the amount of time the microcontroller spends running is smartly managed and controlled, the overall amount of power consumption is drastically reduced. One ideal use case for low power wireless sensor networks is in “smart city” applications. Low-power network technology is optimal for monitoring the condition of things such as parking, streetlights, traffic control, municipal transportation systems (buses), snow plowing, trash collection, and public safety. Data is collected from these devices, then interpreted into meaningful information in a format that allows city employees to make informed decisions about allocating resources and delivering services. In many cases, responses to changing conditions can be made ahead of time and automated, resulting in a “smart city.”