Why aren’t cellular asset trackers getting smaller?
At BinaryTech we specialize in massive IoT technology, connecting everything from beer kegs to pathology samples to the internet so we can gather, enrich, and report on all the real-world data they collect. One question we’re commonly asked is “Can you make your monitoring devices smaller? You know, like an Apple Watch?”. It’s a fair question because wearables operate from batteries, connect to the cellular network, and offer rudimentary asset tracking features (e.g. Apple’s “Find My” utility) just like our own IoT sensors. So why aren’t dedicated cellular asset tracking devices small as well?
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Wearables vs IoT Asset Monitors
Wearables and IoT asset monitors work in entirely different environments. Typically an IoT asset monitor is most valuable when itis a long way from humans. That’s where assets are the hardest to keep tabs on, and typically where assets tend to get lost. Wearables on the other hand typically live on people. And people typically congregate in places with good wireless coverage (or more succinctly, good wireless coverage tends to be provided in places where people congregate). This puts wearables and IoT asset monitors at polar ends of the coverage scale.
Compare the Pair
Wireless asset monitors need to be optimized for wireless performance due to their usage patterns, and their necessity to use energy efficiently. As such, there are two areas where modern “LPWAN” cellular asset trackers excel:
- Battery Life - Operating from batteries, for a very long time without being charged
- Signal Reliability - Transmitting data over long distances, especially from hard-to-reach places
Battery Life
In order to excel at their raison d’etre, asset trackers are designed with generous batteries and large, efficient antennas. While cellular smart watches typically have regular charge cycles i.e. we plug them in every night. In some cases, our devices are designed to last over >10 years, unattended without undergoing battery replacement or recharging. Typically though, the batteries used in our devices are matched to service intervals of the items they are tracking. In some industries it’s once every six months that an asset is serviced, in some it’s 3 years.
‘Generous’ batteries are subjective, but in our minds it’s relative to their purpose. Aspects such as life-span, capacity, physical size and cost all contribute to the choice of the right battery for an IoT device. Ultimately though, extending the device’s operational life-span directly increases its lifetime value making this a priority when choosing a battery.
Signal Reliability
Traditionally, battery life and signal strength have been at odds with each other (pick ONE, not both) but modern LPWAN technologies have really pushed the envelope on what is possible today with long wireless range, and long battery life – allowing modern IoT adopters to have their cake and eat it too.
Wearables often leverage nearby mobile devices to carryout the heavy-lifting of long-distance, cellular communications. Owners of Apple Watches will often notice their watch doesn’t quite get the same level of signal reception as their phone does – your watch is great at being small, not so good at cellular communications in areas of poor coverage.
As IoT asset management devices aren’t constrained by the same size limits as wearables, a third aspect of IoT devices comes into the bargaining arena – antenna size. As a key driver of signal bandwidth and overall efficiency, antenna size can help with the Signal vs Battery Life conundrum.
Antenna Size
In an ideal world our antennas would be roughly ¼ the size of the wavelength of the signal they’re transmitting or receiving, but we tend to make some minor trade offs when bringing a product to market. You can read more about the specifics to do with antennas and signal power in our blog on optimizing radio performance but the TLDR is that efficient, wide-band antennas benefit from a certain size and ground plane.
Choose Any Two
Essentially though, if you are trying to track something reliably in an area with low reception you’ll still need to compromise somewhere. For BinaryTech devices it is better to have a large, efficient antenna, improving on signal power, battery life and overall reliability.
Talk to BinaryTech to see how our IoT asset monitoring can improve your operations. Email contact@binarytech.io or call 1800 BINARY.
