Sensor Node or Sensor Mote-basics of Sensor Node or Mote

This page describes Sensor Node or Sensor Mote with block diagram. Sensor Node or Mote is used in Wireless Sensor Network(WSN).

Following are the basic features of wireless sensor node or mote used in WSN.
• They are self organizing.
• They have long battery life and hence often not replaceable.
• They have less functional and processing capabilities.
• They have been designed to handle low data rate requirements.
Refer Article on WSN basics➤ for more information.

Sensor Node or sensor Mote Block Diagram

Sensor node or sensor mote

The figure-1 depicts block diagram of sensor node or sensor mote. It consists of processing unit, sensing unit, communication unit and power unit.

Let us understand each elements of sensor node as shown in the block diagram:
Sensing Unit: It consists of different types of sensors as per application of choice. It includes thermal sensor, vibration sensor, magnetic sensor, chemical sensor, light sensor etc. The sensing unit measures external parameter with the help of sensors and fed it to the processing unit. If the signal input is analog then it is converted to digital form using ADC (Analog to Digital converter) before being sent to processing unit.
Processing Unit: It does processing as per pre-defined instructions or programs loaded. Micro-controller or processor does this operation. ATMEGA-16, MSP 130 or ATMEGA-128L are commonly used in this unit. This unit performs various tasks and also controls other units of the sensor mote or node. Different processors or controllers will provide different performance criteria based on speed, memory, data rate and peripheral requirements of the system.
Communication Unit: Once the results are ready in the processing unit, they are relayed to the central Base Station unit using communication unit. It consists of RF transceiver and antenna for transmitting and receiving small size packets. In order to have energy efficient sensor node, communication unit has idle and sleep mode in addition to transmit and receive modes.
Power Unit: It provides power to all the other units of sensor mote. It provides such support with the help of battery.

Features of Wireless Sensor Node or Mote used in WSN

Following are the features of wireless sensor node used in WSN network type.
• It should be prone to unexpected failure.
• It should move anywhere in the network coverage.
• WSN nodes should work in any topology.
• In case of failure during communication is in progress, nodes should inform base station.
• WSN sensor node can be of any type and should co-operate with other nodes in the network in heterogeneous mode.
• The number sensor nodes in WSN network should be scalable and should support about hundreds or even thousands of such nodes.
• Any WSN node should work independantly.
• Sensor mote or node should be re-programmable.
• The sensor should provide maximum performance at less power/energy.

WSN-Wireless Sensor Network and Ad Hoc Network related links

Article on WSN basics
Cellular network Vs Ad Hoc network

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