Given that we can now buy modules containing an IMU the rationale for building a Dewbly is called into question – unless we do it for the hell of it.

The technical question to be answered is not quite covered on pages38-39 of the DW1000 User Manual in section 4.5.1 which shows Sniff Mode and Low duty-cycle SNIFF mode.
The basic idea behind sniffing is that the radio turns on and listens at intervals that regularly sample the ether, listening for traffic.  The sniff interval and duration are determined by the peer's anticipated transmission pattern.
So if A transmits a one second packet every ten seconds.  Then B can sniff the ether briefly every second, and guarantee to be listening when the packet is transmitted.  Notice that this does not guarantee that it is heard, or received without error.
The principle is explained well, but unlike at other places in this manual I found no illustrative examples of power usage.   I wonder if we dare ask DW to point us at the relevant information, or to provide some estimates of SNIFF power budget for different latencies?  What do you think?
One reason we are using a Nordic M0 is that it provides an alternative method for sniffing that ought to be lower powered because of the physics of the radio.  But that's not been confirmed.
Maybe we could ask them for an off-the-cuff guestimate of how DW sniffing would compare with (er… to take a random example)  BLE sniffing for a range of duty cycles.

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