Taking a bite out of the IoT energy budget

This article originally appeared in the Jan'23 magazine issue of Electronic Specifier Design – see ES's Magazine Archives for more featured publications.

At CES 2023, Dracula Technologies will showcase its Layer organic photovoltaic (OPV) technology which generates energy from ambient light to charge low power indoor devices, even in low light conditions. It is designed to be applied to IoT products which would typically rely on a battery to connect them to the network. The reason why the company developed a means to harvest energy to power IoT devices is simply one of scale. Having billions of IoT devices using batteries which are thrown away when they are exhausted does not have a positive environmental impact.

Unsustainable battery use

The popularity of the IoT in the home, workplace and factory means that the number of connected devices requiring batteries is growing at a phenomenal rate with at least 50 billion industrial IoT devices expected to be deployed in 2025.

“The situation today is unstainable," says Brice Cruchon, CEO and founder of Dracula Technologies. "The devices that are already deployed . . . consume too much energy and generate too much e-waste: 15 billion batteries are thrown away every year!”

The thin OPV material is 0.3mm thick and has a bending radius of 20mm enabling it to be fitted around most shapes of IoT nodes. It is also lightweight (o.04g/cm²). The company estimates that the energy return on investment (EROI) for not using batteries or heavy materials is 0.35 years when applying Layer instead of integrating a battery in the design.

The elimination of batteries will also reduce the cost and weight of IoT devices as well as maintenance with no battery changes needed. The company uses patented techniques to produce organic photovoltaic modules through inkjet printing and uses special materials that harvest both natural and artificial light.

Printing process

Layer technology generates electricity from as little as 50 lux, which is the intensity of light emitted by emergency exit panels. Using five nano-layers of materials, Dracula prints its Layer modules using conductive ink made from organic polymers derived from carbon which has a positive environmental impact, says the company.

The inkjet printing process means the result is adjustable in terms of dimensions as well as the ability for printing into shapes or curves to meet a particular product design. Customers can specific any shape, even logos. To increase its sustainability credentials, Dracula points out that it operates a ‘drop on demand’ process which means there is less material waste, compared to other printing and coating technologies.

IoT node devices can be covered with the printed PV cells which power sensors or other devices connected to the IoT in industrial or smart home settings, using natural or artificial light sources. It is also bi-facial and therefore able to collect photons from the front and back of the OPV. Once printed, the OPV is suitable for a variety of locations, with an temperature range of -30 to +40°C.

Layer is compatible with a range of communications protocols and can be used for IoT devices in smart office buildings, smart homes, retail and smart factories as well as autonomous vehicles. Product designers can already order a demokit to build prototypes.

A development kit is available for designers to build prototypes and to tailor the technology for IoT devices. At CES, Dracula will showcase an autonomous temperature logger, a CO2 sensor, an infrared sensor and remote control devices powered by Layer.

Plotting a roadmap

Layer can be customised “even adapting to the smallest imaginable format”. Customisation includes the composition of each layer of the photovoltaic module which enables developers to tailor responses which are appropriate for a range of applications, environmental sensors, remote controls and switches, says the company.

Dracula Technologies raised €5.5m, including investment from LoRa semiconductor company, Semtech. The company is entering full scale production soon, with capacity for 15,00 modules per week presently, and expects to produce 10 million modules per year by the end of 2023