Munich, Germany-based EnOcean GmbH, a supplier of energy-harvesting wireless technologies, has introduced a solar-powered radio-frequency (RF) magnet-contact sensor. Labeled STM250, it eliminates the principal deficiency of wireless security systems: the dependence upon batteries. By doing away with the burden of battery monitoring and replacement, the new magnet contact can operate virtually forever without costly maintenance, said the developer.

“The security industry has long had a need for simplified magnet-contact sensor installation and operation. Wireless seemed to provide the answer, yet the cost and consistency of battery power has been a recurring concern,” said Jim O'Callaghan, vice president of EnOcean. “By combining solar power with robust RF technology, EnOcean has effectively merged all the benefits of wire — affordability, stability and reliability — with the convenience of wireless.”

Whereas a typical wireless security system achieves long life through the use of expensive high-quality Lithium-ion batteries, STM250 requires only ambient indoor or outdoor light. The amount of light typically available in homes or offices is sufficient to both operate STM250 continuously and to store energy for up to six days use in total darkness.

Even though the STM250 uses surprisingly little energy — which it gathers via its tiny surface solar cell — it generates sufficient output power to communicate throughout an entire house. The unit's embedded EnOcean RF transmitter will send a signal across 300 meters outdoors and 30 meters indoors through walls. The secret is in its signal duration: the entire transmission is initiated, undertaken and completed in approximately 1/1000 of a second.

Not only does each module offer a comfortable range; it also assures dependable communication. Its suite of sophisticated RF protocols includes multiple broadcasts, fast data rates, error detection and unique addressing. STM250 automatically transmits its signal immediately when the contact is opened/closed. What's more, a periodic presence signal is sent on the quarter-hour to indicate that the node is operating properly, using stored energy.

Packed into a small 109 × 17 × 16 mm inch device — smaller than a standard doorbell — the STM250 includes a solar cell energy generator, an energy reservoir, a reed contact switch, a microprocessor for sensor control, and a radio transmitter and antenna. A separate magnet is provided.

STM250 will serve either as a ready-to-install switch for security system contractors, or as an OEM-level product for integration into doors and windows. Thanks to its intrinsic stability, it can even be permanently embedded inside impossible-to-reach places, such as between panes of window glass.

Out of the box, it quickly acquires sufficient energy to run — 10 minutes under normal indoor light. The system provides unmatched simplicity through an ingenious “learn-in” programming feature that doesn't require time-consuming PC programming or personnel training. Due to its fast transmission rates, hundreds of magnet contacts can be connected to a single receiver without system degradation. In addition, it can also serve applications such to conserve energy, HVAC equipment automatically shuts off if a window is opened, to disable exhaust-emitting equipment like indoor grill ovens, stoves, heaters, etc. unless a window is open, and warning indicator that cargo containers or trailer cargo doors have been opened.

To simplify the OEMs development of their wireless network, EnOcean provides a family of receivers and transceiver/repeaters compatible with all switch and sensor modules. The proprietary radio technology is approved for use in Europe (ETSI), the United States (FCC) and Canada (IC).

For more information, visit www.enocean.com