Capturing Ambient Photovoltaic Energy to Achieve Forever-Battery Life and Drive the Battery-Free IoT

Now more than ever we must put the energy sourced from the Sun and lighting to work

The practicality and convenience of connected IoT devices continues to grow as they literally change the game, taking efficiency to new heights and streamlining operations for virtually every industry, including manufacturing, agriculture, medicine, transportation, real estate and more. You name the industry, and there’s a way that connected IoT sensors and trackers can change the way that companies do business. And for consumers, IoT devices are delivering new experiences that we could only have dreamed of – just think about how smart speakers talk to consumers and wearables help users track their health and fitness. Given the multitude of advantages that the IoT can bring, ABI Research predicts installed base for Bluetooth, Wi-Fi and NFC devices will be more than 35 billion globally by 2023.

It’s great to see the progress that industries are making with connected IoT devices, but along with these advances comes a big concern: how to deal with the challenges of batteries powering the billions of devices. Batteries are costly to maintain and also do long-term harm to our environment when they are discarded.

The team at Atmosic – which is expert in wireless communications and low-power silicon solutions – has focused all its efforts to help solve the battery dilemma of the connected IoT. Atmosic has created ultra-low power solutions that can enable forever-battery life for connected devices, and even enable devices to be completely battery-free.  

Bringing Energy Harvesting to Maturity

The first step to enabling energy harvesting was to create an ultra-low power connectivity solution. When the connectivity doesn’t consume a lot of energy, even modest amounts of harvested energy can be sufficient to power an IoT device. Atmosic created our Lowest Power Radio and On-demand Wake Up technologies to dramatically lower power consumption, enabling the batteries powering devices to last forever. Learn more about our M2 SoC series here.

Secondly, Atmosic combined its ultra-low power connectivity advancements with energy harvested from ambient radio frequencies (RF), thermal, kinetic and photovoltaic – including both solar and indoor/outdoor lighting – energy sources to develop its M3 SoC series.

With its photovoltaic energy harvesting, Atmosic’s M3 series is ideal for large connected IoT deployments, such as networked wireless, location-based sensors in venues such as hospitals, malls, stadiums, entertainment venues, factories, retail stores and enterprises. Imagine the massive battery maintenance required of such deployments, which consumes time, money and potential down time if batteries are short lived and need to be frequently re-charged or replaced. With Atmosic’s Bluetooth® connectivity M3 series solutions powered by energy harvested from either the Sun or lighting, it’s feasible to power large deployments of sensors or other devices with a tiny battery that lasts the lifetime of the device. And some devices with Atmosic’s M3 don’t even need a battery at all.

The M3 series has been designed to store harvested energy in a variety of ways to enable flexible product design and implementation best suited to specific application requirements. The M3 supports power storage with three scenarios where power is stored, as depicted in the images below:

  • Supercapacitor for “battery-free” operation
  • Standard battery for “extended battery life”
  • Rechargeable battery for “forever-battery” operation

The M3 is a self-contained solution, integrating:

  • An ultra-low power Bluetooth 5.0 solution
  • An advanced power management unit (PMU) to manage multiple energy inputs for the battery and harvested energy from external sources (RF, photovoltaic, thermal and kinetic)
  • Connection to a storage capacitor (or rechargeable battery) which collects excess harvested energy

Photovoltaic power, sourced from either the Sun or light, can be captured by a photovoltaic (PV) cell. Think of it as a tiny solar panel or screen integrated into the product design and used to capture light energy. Atmosic has teamed up with partners providing PV cell solutions in a variety of sizes and configurations to address the needs of different product applications and design configurations. For example, a battery-free beacon can be powered by light captured indoors with a cell roughly the size of two postage stamps. Devices using more power will require proportionally larger cells.

In the case of beacons, the energy required to sustain the beacon depends on the beaconing interval, the packet size and transmit power level, all which impact the consumed energy.

For example, a 10 cm-squared PV cell can support a battery-free operation for:

  • Beacons powered by high/retail light levels that transmit information every 100 milliseconds
  • Beacons at office lighting levels that transmit information every 200 milliseconds
  • Beacons in low light environments that transmit information at two second intervals

With a clear understanding of the operating requirements for connected IoT devices like beacons and sensors, savvy OEMs can design products that can readily sustain operation for the life of a device – without a battery or with a “forever battery” that automatically recharges for the life of the IoT device.

The Atmosic team has created proof of concept designs for commonly used IoT devices, powered by photovoltaic energy harvested by the M3, including a PV-powered beacon, remote and keyboard. Each of these designs integrate a PV cell that’s the equivalent size of half the width of a credit card, or roughly 5cm x 2cm. You can see these in demonstration here.

These are just a few examples of what can be achieved with the energy harvested from the Sun and lighting, and are the start of our quest to help deliver a battery-free and forever-battery connected IoT. For more information on how you can integrate ultra-low power Bluetooth connectivity and energy harvesting from many different ambient sources into connected devices, please contact us at info@atmosic.com.

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