Design More Power-Efficient IoT Devices

Design More Power-Efficient IoT Devices

The things we have around us and interact with have intelligence. That’s why we want to connect them to the internet. But it hasn’t been feasible or practical to bring everything online. For example, the sensors and actuators that can bring intelligence to the things around us come with some big power challenges. It’s not ideal to run power to, say, a front-door sensor, and frequent battery replacements are a turnoff to consumers. Large batteries can overwhelm an application, and harvested energy sources like solar aren’t always available.

To free the invisible intelligence around us, we need to figure out how to provide power to that intelligence.

What is Invisible Intelligence?

Inspired by the idea that the best technology fades away, invisible intelligence is based on three key principles:

  1. The things we interact with and have relationships with have data, and when enabled by technology, this shouldn’t fundamentally change the way we interact with them.
  2. We shouldn't notice that the smart device is fundamentally different from its 'dumb' counterpart (hence its invisibility).
  3. The data from our smart device needs to have value. Invisibly intelligent things will inherently be more expensive than their dumb counterparts.

Now, let's look at how these three principles relate to our original question about powering the IoT.

  • Interaction: Batteries or other harvesting mechanisms can’t hamper people’s use of a device. Can you imagine having to turn a hand crank to operate your smart thermostat? It’s not just about physical impediments, either. For instance, battery charging is also not generally part of our interaction with most devices. Who would want a smart doorbell if it needed daily recharging?
  • Appearance: Aesthetics and practicality do matter. Consider a view through a window being blocked by the battery of a smart window sensor, or a smart ring that looks bulky because of the battery.
  • Data: As with any product or in any business, the 'return' needs to outweigh the 'investment.' Exotic harvesting mechanisms can drive up the cost of an IoT device, as can battery replacements. So these are important considerations when evaluating ways to power your connected product, so it can do something useful with the data.

Smart, connected kitchen appliances are examples of IoT devices that must be efficiently powered to be effective.

We're already seeing many IoT devices in mass deployment. Wearable devices like fitness watches are among the most popular—and they're answering these power questions while successfully exhibiting 'invisible intelligence.' We interact with fitness watches much as we do with their traditional counterparts. Charging them doesn’t really disrupt our interaction with them, as it's something we can do when we remove the device at night. Fitness watches also, for the most part, maintain the appearance of regular watches. Most importantly, they provide a wealth of valuable data, including calorie count and multiple health parameters.

Many other connected devices are also adding more sensors to help provide more data. But more sensors, more connectivity, and more algorithms mean more power, and bigger batteries or more frequent recharges are never a part of a good user experience.

Managing the Power Budget

The real promise of the IoT—that we can get valuable data from everywhere—can only be fulfilled if we can shed the power cords and get data from things that aren’t tethered to an infinite power source. How can you make the most efficient use of the battery inside these devices? This is where having the right low-power microcontroller can help. In my white paper, "Powering the Next Generation of Smart Devices," I discuss parameters to consider when evaluating low-power microcontrollers. Read the paper today for more insights and techniques to help you develop power-efficient IoT designs.