RTLS overnight stability issues


#1

Hi all,

We are consistently finding that when we leave the RTLS system running overnight, by morning, the system is no longer updating tag locations. Furthermore, when we reset the system, almost no anchors are sending out announcement packets (we have one that does on some resets but not always).

Could this be a battery problem? We tried the following experiment, which seemed to suggest that it is not a drained battery issue:

  1. Shut down the master
  2. Unplugged the master for 30 seconds
  3. Plugged the master back in
  4. Observed no announcement packets from any anchors over about 45 seconds
  5. Took an anchor down (from ceiling, thus a bit difficult to check each one) and observed no LED blink
  6. Unplugged the anchor
  7. Plugged the anchor back in to same battery and observed no announcement packet and still no LED blink
  8. Changed the battery and observed immediate announcement packet and corresponding yellow blink
  9. WEIRD PART: changed BACK to the original battery and observed immediate announcement and yellow blink

So rather than a dead battery, it seems a stability problem. Possibly related to a battery on low capacity?

Has anyone else seen this and know of a workaround?

Thanks,
Micah

P.S. FYI, I signed up with my personal email, as my corporate email would never receive the activation email, even in my junk folder.


#2

On further investigation, it seems this is related to battery drain. When we swapped the batteries for fresh ones, the anchors all came back immediately.

So there does seem to be some amount of non-determinism regarding whether the decawave board will come up on a mostly drained battery.


#3

As of May 11th of 2016, the demo firmware for the DWUSBs has not yet been optimized for power efficiency. Because of this, we would not expect the batteries to last through an entire overnight test.

We can verify that we were able to reproduce the inconsistent behavior of the DWUSB when attempting to run on a battery as it reaches the limit of its capacity, so that is something to be aware of when performing long-term testing with batteries powering your anchors.

Also, thank you for informing us of your issues with the activation email process. We’re already looking into this problem, and when we find a solution, we’ll let you know.