Overcome power budget limitations to achieve breakthrough IoT systems

Batteries are convenient, but constraining

Batteries that power IoT devices pose a solution, as well as a problem. While they serve as portable power options that are quick to install anywhere, batteries also impose strict power budgets and limit device functionality.

For example, while wireless security cameras may be easy for homeowners to self-install due to the lack of wiring involved, batteries are known to quickly deplete. Constantly changing batteries is a hassle, and homeowners are often left wishing they had invested in wired systems that offer features such as streaming video. Similarly, smart locks require constant battery replacements in order to power the device, and even more so if the user wants video recording, biometrics or cloud storage.

An executive from a smart home products company we recently spoke with gave some insight into challenges they face regarding powering IoT devices. “At first,” he said, “we wanted to make sure customers don’t have to replace batteries more than once a year, but we realized we could not fit the features we wanted under those power constraints.” He added, “Ultimately, we decided that the need to replace batteries every six months would be okay, so we could include the features most desired in the product.” Whether you agree or disagree with this executive, this exchange illustrates how battery power handcuffs solution designers.

Let’s assume the device is using four high-end AA alkaline batteries — likely too large for some IoT devices, but it’s a good reference point. If the batteries need to last one year, the average power consumption is only 0.002 watts. Compare that with wired devices that can take 1, 5 or even 50 watts. You can begin to see the problem. This huge gap explains the dramatic functionality difference between battery-operated and wired devices.

Would wired devices serve as a better alternative?

While some may believe that wired devices are the solution, they carry their own set of problems. Consumers can’t easily install wired IoT devices themselves without having a background in electrical wiring or fishing wire through walls, and, at an average cost of $100 per hour for labor, professional installation is quite expensive. Also, if a problem arises with a wired IoT device, installation teams are required to make a service trip to the home or facility to troubleshoot and resolve the issue.

The concept behind long-range wireless power relies around three simple steps:

1. An energy transmitter converts electrical energy into some physical phenomena.
2. That physical phenomenon travels through air to reach an energy receiver.
3. That phenomenon is converted back into energy on the receiver side.

There are different approaches to make wireless charging a reality, including radio waves, ultrasound and infrared light. When looking into options, product designers need to investigate a few key parameters:

• How much energy can be available for the receiving device? At what distance?
• What is the transfer efficiency?
• How large are the energy transmitter and receivers?
• Is it safe? Are the quoted values within the regulator’s (FDA, FCC, etc.) tolerable limits?

Using the light spectrum for energy delivery

One promising alternative is long-range wireless power that uses infrared (IR) light. It is promising for several reasons, the first being that IR light is natural light. About 50% of the sun’s energy is IR, so humans have already been living with IR for millions of years.

Light can travel in a thin, straight line. For instance, with a laser pointer you can shine a small dot on a wall from far away. In the same manner, an IR transmitter can focus a tight energy beam on a small receiver. This means high efficiency, and that all or most of the transmitted energy reaches the receiver and that little or no energy leaks into the environment.

Energy transmission using IR light can safely deliver hundreds or thousands of times more energy than batteries or other wireless charging methodologies due to the fact that the transmitted energy significantly dissipates the further it travels, limiting the usable energy available at the device level. The combination of power, distance and safety of IR holds significant promise to product designers and end users alike.

What’s the future of wireless power and IoT?

Regardless of approach, wireless power is not always the right answer. Sometimes a battery provides plenty of energy for a particular sensor. If a device needs a new battery every five years, wireless power might not be a high priority. By the same token, if an IoT device needs tens of watts, wireless power might not be able to deliver the amount of power required. Sometimes, it is not practical to install an energy transmitter within reasonable distance of the client device.

Long-range wireless power can absolutely be useful as a third option for energy delivery. If power cords are cumbersome and batteries are insufficient, wireless power can be an alternative. Designers equipped with much more than batteries can create breakthrough IoT innovations, simplify installations and put the power back into consumer’s hands. Wireless power is not a perfect fit for all applications, but forward-thinking companies will soon consider this technology and the benefits it provides.

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