- In many Internet of Things (IoT) applications, minimizing power consumption is a key design requirement.
- It is often not feasible to add wiring, so a battery-operated solution is a preferred option.
A sensor node is a compact device which is used for sensing the environment and providing the data to a system through wireless communication. The device works on low power consumption and hence are made to work over small batteries for years. Improving the lifetime of a sensor node with limited battery is a key feature of Wireless Sensor Network technology.WSN uses data compression technology to reduce total power consumption.
IoT capability involves adding sensors and connectivity to a location where external power available is very difficult.
Some of the Key Parameters while designing a Low Power Sensor node are –
- The node should have a small and compact size. Nodes have a wide area of application in wearables and small deployable sensors.
- The power consumption of the developed node should be as low as possible. This is essential because nodes generally work on battery-powered sources and they have limitations in terms of Amp-hour capacity and discharge rate for current. To overcome these limitations, the device should be designed in such a way that it has low power consumption and can work for a longer period on the same battery-powered source.
- The main application of a sensor node is to sense and send. It means the node sense a particular factor of environment and sends the sensed data over a communication channel. As communication plays an important role in data collection, the node should support multiple wireless communication protocols for data synchronisation.
- The node should support sleep scheduling methods. Generally, sensor nodes work on sleep modes. It means the sensor will only be active when an external interrupt (hardware or software ) is generated in the controller. It helps in decreasing the total power consumption and hence an efficient method for nodes working in Wireless sensor network.
- The microcontroller is the brain of any portable electronic system. The microcontroller should have a higher clock speed for fast processing and multiple clocks to synchronise with other compatible peripherals.
All of these factors should be in consideration while designing an efficient low power node.
The key features provided by the Reference design is –
- It is Integrated with a 6-axis accelerometer and magnetometer.
- It is designed to work on 3.7 Volts 1200 mah li-ion or a lithium-polymer battery.
- It works on 2.4Ghz ISM band and supports 802.15.4 IEEE protocol including WiFi and ZigBee.
- It works on a 32 kHz clock and supports multi-processing.
- The output signal power of the design node is programmable and ranges from -35 dBm to +8 dBm.
- It supports I2C protocol for easy interface and uploading of firmware through Windows or Linux platforms using JTAG.
IoT based Nodes has a very wide area of application such as –
- Medical Devices
- Remote Sensing Applications
- Industrial IoT
- Smart Wearables
- Wireless Mesh Networks
- Development of RFID Tags
The reference design includes all the essential details regarding PCB manufacturing, Design Schematics and Bill of Materials. It can be downloaded here.