Home/Away status - Fine tuning

[PaulLeadbeater1]

This is my first contribution. Sorry if it's not exactly set out as it should be.
I have Bermuda running on an HA Blue (yes they still exist!). I am using Blue Charm ble beacons as the source, fitted to cars in my driveway. I am only using detection for the cars being on the driveway or not on the driveway.
With my current settings Bermuda reports devices as being 'Home' (when they are home) consistently (so far).
Bermuda also reports devices as 'Away' when the cars leave the driveway and 'Home' when they return. So far, so good.
When a car returns to the driveway, Bermuda picks it up quickly and correctly reports 'Home'.
When a car leaves the driveway, however, Bermuda is slow to detect it leaving and hence slow to report it 'Away'.
As I'm not sure exactly how Bermuda evaluates the data to report Home/Away, I'm not sure what adjustments should be made to improve the 'Away' detection.
Can you point me to any information on Bermuda's calculations for the 'device tracker' which will help fine-tune it's responses?

[agittins]

Hi Paul!

The first thing to keep in mind is that the only "fact" that bermuda gets from the world is "I just saw this thing". Nothing ever tells us "I can't see this thing", because we have no "proof" of a thing being not there.

So all we know is that at times, we know the thing is there, but at other times we get nothing, and at some point we need to decide if we think it's gone.

For the device_tracker, we use the Device Tracker Timeout setting, in Bermuda's CONFIGURE, Global Settings screen. The default is I think 5 minutes (300 seconds), which gives a pretty reliable indicator for most situations - if we don't hear anything for 5 minutes, we mark the device as Away.

You can reduce that timeout to whatever value suits your particular use-case. As with everything in life though, this is a trade-off. The shorter you set the timeout, the more likely (and more often) you will get "nuisance triggers" - bluetooth is a "best effort" thing - devices just spit out advertisements, and maybe we get them, maybe we don't.

So you can adjust the value down until you start getting false indicators for Away, then increase it a bit.

If you want something that will lock doors for you etc, then you might be better off using a trigger that is conclusively affirmative (like "the lock button was pressed") rather than an assumption ("haven't seen the car lately..."), but it all depends on what works for you.

[PaulLeadbeater1]

Hi Ashley,
Thanks for this comprehensive explanation. I'll try lowering the timeout setting and see how it goes.
Have to say that Bermuda is the most stable system I've found so far; probably related to how good the calculations going on behind the scenes are. Others have problems with lack of consistency in their reporting - something which is no good for HA automatons and not really fast enough for my use, where I'm trying to detect cars when they leave a driveway, not when they're half-way down the road!
I'll report back how I get on with your suggestions.
Cheers,
Paul

[PaulLeadbeater1]

Latest update.
I still can't get the settings to work reliably to detect cars on/off the driveway.
I'm trying a different approach now. Using a feature of the Blue Charm beacon where it can be set to only transmit on motion, I'm going to use a Home Assistant automation to detect the motion and maybe an Input Boolean to determine if the car's coming or going.
I realise this is moving away from what Bermuda is designed to do - maybe there is no good way to use tracking beacons for what I'm trying!