Home Control Assistant Newsletter for Feb 20 2022

Have you read the Important Announcement posted on August 1, 2021? If you haven't you need to.
Got a story to tell
This week I’m going to tell a tale which isn’t HCA related. Consider it a story of a playful pat on the head to remind us that sometimes we must think outside our dogma. May be useful to us all as we design and develop our automation strategies.

As you know I don’t just “do” HCA. I have other projects that are on-going. One of those has proved over the last year to be very vexing. It was one of those situations where it “worked for me” but for some users it “never worked for them”. Try as I might, I couldn’t ever come up with a reproducible case that failed even though some users saw failures “all the time”.  What made it even more difficult was that the software in question was firmware inside a device with very limited debugging capabilities. And it was firmware I didn’t create so I didn’t intimately know it.

For many months I tried to come up with test cases that would reliably and reproducibly show the problem.  Since the device is connected to a network – ethernet cable – I was never sure if it was a network issue or something else. And it could be due to some firmware changes that were made last year.

The firmware developer and I strategized on possible points of failure, and I created test cases to hopefully cause them to happen. Mostly I was unable to do that, but we did change the firmware in several ways to make it better.

Last week I decided to do a “breadth” test: I started up many of these devices. Three on one network and two on another. Some with the latest firmware version and others with an older version. I used different operations – some connected to clients and others not. And then I just let the test go for several days.

Two failed with the “problem”. There was enough overlap of test parameters that one failed device was configured and used in the same manner as another that didn’t fail.

I think I have said this before: “I never think a problem is the hardware”. Too many years of programming “close to the hardware” has shown me that hardware issues are vanishingly small.

But, alas, not this time. I asked the engineer who created the device if they had made any hardware changes. One of the failing units was from an older manufactured batch and the other working and identically configured unit was newly manufactured. Turns out they had made a change to a resistor value in one circuit. That circuit is involved in communication between two major modules of the device. Since these two modules are inside the same box the firmware never assumed that communication could fail.

So, do we have the solution? Is it really is solved, and I can’t say for sure yet, was the “fix” due to all the firmware changes or the hardware issue? Probably a bit of both. Before calling it quits, I would like to see the firmware changed to better handle the internal communication problem that this mis-valued resistor caused inside the device.

As I often say: “If you hear hoofbeats think horses and not zebras”. But this time it really was zebras.

If you are using a version of HCA prior to version 17, you may have questions about the wisdom of upgrading to version 17 given the future of HCA. Here is something to consider:

The support policy for older HCA versions has been changed
 as I can no longer devote time to past version users. Support will only be available for HCA 17 users.

If you are on version 16 or earlier and want to continue using the cloud features and want to be assured that if you have a question that it gets answered, it is indeed time to upgrade.

HCA is fully operational for several more years so the update cost, spread out over that time, is very little. Knowing support is available when you need it is worth it.
Upgrade to HCA 17
Anyone who is using Hubitat with HCA – not SmartThings – please drop me a note as I would like to add you to a discussion list for those users. I have some Hubitat ideas that I would like to “kick around” and it would help to have a group of users who have experience with Hubitat. Please just send a note to the regular support address saying you would like to be added to that discussion list.
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