Pushing the Life of Asset Tracking Tags From One to Five Years
While asset tags are a critical puzzle piece to Industry 4.0, these devices are plagued by short battery life. Now, onsemi has literally stretched the lifespan limits—to five years.
When Bluetooth Low Energy (BLE) was released a decade ago, it enabled a new class of devices and applications that were previously thought unattainable. Amongst these applications, asset tracking tags have benefited largely from BLE thanks to its low power, high reliability, and low cost.
BLE is now being used in 50 percent of trackable asset tags. Image used courtesy of onsemi
Since then, the rise of Industry 4.0 has created new “smart factories” where asset tracking has become an integral part of production. Still, for Industry 4.0 to reach its full potential, engineers must unlock further power savings for their asset tracking tags. Last week, onsemi addressed this power challenge with its new asset tag, which the company says offers a battery life of up to five years.
In this article, we’ll discuss the challenges facing low-power asset tags and see how onsemi is approaching them.
Low-power Techniques for Asset Tags
Oftentimes an IoT device like an asset tag will spend more time doing nothing than it will spend transmitting. Hence, one of the major ways to improve battery life in these devices, beyond simply using lower-power components, is to minimize quiescent current consumption.
The main culprits in the case of an asset tag are generally the MCU, the RF transceiver, and connected sensors.
Power consumption in active vs. sleep mode for an MCU. Image used courtesy of ADI
MCUs in general are able to limit their power consumption by leveraging sleep modes, which will shut down major circuit blocks when the device is not in use. We can do similar things with an RF block, but it still requires a relatively large amount of power in order to perform any RX/TX.
While hardware-level optimizations are important for lowering quiescent and active power consumption, power savings in RF blocks come largely from the algorithmic and protocol level. For this reason, many IoT devices leverage BLE connectivity, a wireless protocol that allows very low-power connectivity.
Finally minimizing the power consumption of sensors can often be achieved by power gating the device: cutting off connection to the device’s power supply entirely until it’s to be used. While a simple MOSFET can suffice, a better solution tends to be a dedicated load switch, which is optimized for this purpose and allows for the handling of system subtleties.
The RSL10 Asset Tag
This week, onsemi released its new RSL10 Asset Tag, which is said to offer a battery life of up to five years.
The company attributes the RSL10’s low power consumption largely to the RSL10 Bluetooth 5 radio SoC. The SoC features a dual-core architecture based on an Arm Cortex−M3 processor alongside a LPDSP32 DSP core and also integrates an on-chip 2.4 GHz transceiver.
Engineered to be low power, the SoC features deep sleep currents in the nanoamps and TX/RX currents below 2 mA. As the heart of the RSL10 Asset Tag, the RSL10 SoC allows the device to be extremely low power while supporting BLE protocols.
RSL10 Asset Tag. Image used courtesy of onsemi
Beyond this, RSL10 Asset Tag integrates a 3-axis accelerometer and environmental sensors including pressure and temperature sensors. To maintain low power, each sensor is powered through a dedicated MOSFET load switch, controlled by the SoC. This enables the overall system power consumption to be controlled on a per-sensor basis, effectively decreasing total power consumption.
A high-level system block diagram of the RSL10 Asset Tag. Image used courtesy of onsemi
Additional integrated features include a low-cost antenna, a BLE-optimized matching circuit, and a 10-pin debugger. onsemi sees applications of its new tag in fields such as Industry 4.0 and healthcare.
This claim of a five-year battery life stands as an important improvement with the rise of Industry 4.0—especially considering that top-shelf consumer tracking tags like Tile or AirTags get a standard battery life of one year on a CR2032 battery.