We are currently developing a low-power embedded system (Security Tag) that is able to run for months without battery replacements (long lasting battery is a must). The Tag will be in a sleeping state most of the time. It will need to wake up and process some data only when it passes through the particular checking area (let's say between the gates). Passing through the checking area should generate some kind of an interrupt event to wake up the processor. We are thinking that we could use some RF signals that, received and processed by the appropriate circuitry on our Tag, will be able to trigger waking up procedure (processor interrupt). Of course, it can happen that there are some other more efficient waking up approaches. We are open to suggestions.
We know that wireless waking up exists as a concept in the world of Wireless Sensor Networks (WSNs). Each WSN node has its own wake-up receiver part that is in charge to receive RF signals and wake up the rest of the electronics on the node. There are many scientific papers on that topic and, yet, not enough commercial solutions. There is a company on the market (Austria micro systems) offering some 3D RF/RFID Low Power Wakeup receivers:
We would like to hear your opinion on how we can wirelessly wake-up our Tag. We would like you to advise us how to design the part that will generate waking up signal as well as the part of the Security Tag that will be able to receive that signal and wake up the processor. The system should be somehow immune to noise (the present random RF signals that could wake up the Tag by accident).
It is also worth mentioning that generating wake-up signal is energy independent - it does not need to be energy efficient since we can use a power supply from the AC/DC converter.
We have the ability to make the prototypes for both emitter and wakeup receiver, we would like you to guide us through the designing procedure (provide us schematics and some other support if needed).
Thank you very much for your time and effort.