Thanks to the wireless and battery-free switch technology from ZF, there are various possible application fields to increase connectivity, flexibility, and convenience. Bus stop buttons are another smart application integrating the inductive RF generator module. The target is to avoid cabling (up to 100m) and expensive maintenance work caused by cable breaks in buses. The energy harvesting switch guarantees design freedom and reduces maintenance work to a minimum as it has a lifetime of over 1,000,000 switching cycles.
The energy harvesting switch can be integrated directly into the plastic housing of the stop request buttons in buses. The compact design (20.1 x 7.3 x 14.3 mm) makes it easy to integrate. In addition, the ZF radio switch generates a voltage pulse by mechanical actuation as it relies on the inductive principle. Therefore, RF commands can be reliably sent via commercially available radio protocols such as EnOcean3.0 at a frequency band of 868MHz. In this case there is no risk of RF interference with Bluetooth devices which operate at a 2.4 GHz frequency range. Altogether, the radio switch is completely free of batteries or cabling, allows a reliable RF transmission and offers a high degree of flexibility when it comes to mounting in buses.
Each RF switch has a unique ID and can be programmed individually. This means that each stop request button can be assigned to a specific command group, such as opening doors at the front, back, or initiating measures for wheelchair users. The buttons are paired to the central receiver unit, which is again connected to the electrical bus system. Depending on the received command, the receiver triggers a visual or acoustic signal to give the bus driver appropriate instructions.