I'm looking for a low energy communication method for a system that will involve multiple PIR motion detectors for a wireless alert system but not sure what the best wireless solution is. The system will be battery powered so RX current draw is particularly important and must be as low as possible. The Tx part of the system only be powered on during motion alert events (which will only be 2-4 times a day), while the Rx part is always awake and listening. The Tx frequency doesn't matter and could be anything as far as I'm concerned, the range will be ~20ft outdoors, I would like to be at or below 6mA for Rx current if possible. I will ideally want a number of channel options (10+ if possible) or a method from distinguishing certain Rx modules so that I can take different actions depending on which Tx is communicating.
I won't be transmitting data so to speak, but more of an interrupt alert that motion was sensed so even an FM transmitter could work. I was looking at the the Zigbee but the Rx current seemed to be too high but those Rx current draw values are still not clear to me. The systems will also be enclosed in a waterproof box outdoors but subject to a large range of temperatures.
The wireless part of the system will look something like the picture below but instead of three Rx modules, each connected to 3-4 Tx modules, there will likely be 10 Rx modules each with 3-4 Tx module connected; and thus the need for many channels.
Thanks for you time.
