EnOcean Employs Energy Harvesting for Bluetooth Switch Module

January 30, 2024 by Arjun Nijhawan

The company has now released the second generation of the "world’s first energy-harvesting Bluetooth switch module."

Sustainable IoT company EnOcean recently introduced the second generation of its PTM216B Bluetooth switch module, adding to the company’s growing portfolio of NFC-equipped, energy-harvesting devices. 

The company's energy-harvesting portfolio converts energy from kinetic energy, sunlight, and thermal energy into electrical energy or radio waves. EnOcean's second generation of its PTM216B Bluetooth switch module harvests kinetic energy to generate ultra-low-power Bluetooth signaling for various applications. Its design doubles communication power, allowing for larger communication distances. 


PTM216B module

The second-generation PTM216B module has increased communication distance. 


The company says the latest generation of this device will be particularly suitable for high bay lighting and mesh network lighting control solutions. 


From Kinetic Energy to Bluetooth Communication

The switch uses an energy bow and power converter to convert the kinetic energy generated when the button contacts are pressed to Bluetooth signaling. While specific design details are not publicly available, the user manual indicates that the switch converts the motion of the energy bow into electrical energy, which is then fed to the power converter. The power converter generates a DC voltage (which is one of the inputs) to an on-switch processor.

Energy harvesting using the power converter allows the switch to be completely battery-free. The processor takes two other inputs: one from the button contacts and another from an NFC interface. 


Block diagram of PTM216B Bluetooth switch

Block diagram of PTM216B Bluetooth switch. 


The NFC interface allows users to read and write certain product parameters to the switch, such as the radio channel frequency, within the allowable Bluetooth radio frequency band from 2,402 MHz to 2,480 MHz. There are two sets of button contacts—one for Channel A and one for Channel B—and each channel has two contacts for a total of four button contacts. The status of these contacts is transmitted via Bluetooth using the following button action encoding.


The PTM 216B's default button action encoding

The PTM216B's default button action encoding.

The switch also securely transmits the data using AES128 encryption. A signature algorithm generates a unique signature for the switch based on the source address, telegram data, and sequence counter. The receiver uses the same algorithm and only validates the data transmission as trusted if the generated signature matches the received signature. 


EnOcean's Energy-Harvesting Portfolio Grows

The PTM216B module is one of dozens of energy-harvesting devices EnOcean offers. EnOcean sells standalone kinetic harvesters, self-powered sensors, transceivers, and IoT software kits. According to the company's technology page, NFC enables quick and easy device configuration for its portfolio. 



All images used courtesy of EnOcean.