RFID-die: battery-free orientation sensing using an array of passive tilt switches

We here demonstrate the combination of tilt switches with RFID for building fully passive orientation-sensitive devices. We show the functionality of this approach with a simple die that can be read out with an NFC-enabled smartphone. As the proposed orientation system does not require battery powering, it is of interest to various wearable-computing and smart-home applications that benefit from long system runtime.