APPLICATION: Remote sensor nodes capture, store and transmit data with limited available power, using a small battery or harvested energy.
PROBLEM # 1:
Sensor data is lost before transmission due to limited available energy.
PROBLEM # 2:
Battery drains quickly due to high sensor node power consumption.
An IoT node captures and stores sensor data, then wirelessly transmits it to cloud storage. Power is often supplied from small batteries or capacitors charged by solar panels or alternative sources. The limited energy budget requires the system to be optimized for low power operation.
When logging data, the MCU and memory must minimize power consumption while ensuring reliable operation and secure data store. To ensure reliable data-logging and data transmission when using limited power sources, data is coalesced in local memory, then transmitted to the cloud with a limited duty cycle.
Wireless transmission is the most power consuming task in IoTs. Storing the sensor data locally and transmitting in bulk can significantly improve the data sample size and the sampling interval without compromising the quality of wireless transmission of data. This can help improve the power usage and quality of services (QoS) in energy harvested or small battery based IoT nodes.
Low-power F-RAMs, used as local storage, play a pivotal role in these architectures due to faster writes with instant nonvolatility, low power modes and virtually infinite endurance. F-RAMs are more reliable and consume less energy when compared to other nonvolatile memories such as EEPROMs. IoT nodes using low-power F-RAMs can collect more samples per charge and transmit the stored data after longer intervals, rather than immediately after every capture. This saves significant energy that would have been consumed to power the radio in the absence of local storage. Use of F-RAMs helps to optimize the energy usage between data capture and wireless data transmission.
This demo has 3 configurations to showcase the value proposition of F-RAM:
- F-RAM as local storage
- EEPROM as local storage
- Direct transfer without any local storage
- In local storage mode, 16 samples are first collected and stored locally before transmitting over BLE
- In direct transfer mode, every sample is collected and transmitted immediately over BLE
The demo GUI plots sensor data throughput for each of the IoT nodes over a given time