What if your gadget needs a memory card... that is no longer available?

Column + Datatalk + Homematic

Is this a column? Not exactly, but a recent event made me realize that technology fails, and that sometimes we depend on that technology in very essential ways. Take heating. My heating failed (or appeared to) because of a failing SDHC card.

(Lots of interesting reading on ageing of SDHC cards you'll find here and here. And here.)

Floor heating using a CCU2

I run an old Homematic domotics setup in my home since 2014 (maybe a bit earlier) using a CCU2 and some Homematic radiator valves. It's an essential bit of hardware, as it controls my floor heating setup. I have some spare parts (unfortunately I couldn't find a spare HM-LC-SW4).

With the winter coming I was inspecting my heating system and had a look at the diagrams, to see if the valves did properly open etc.

The diagram told me they did not.

The diagram may have lied.

The diagram told my my Homematic system had opened the valves at 04:00 or so at night, then again at 06:30. The 06:30 was correct (floor heating is notoriously slow) but the 04:00 wasn't.

I rebooted all the components, reinserted batteries in the valves, and sat down to ponder. Everything seemed to work...

Did I miss anything?

Only then I considered the small micro SDHC card that sits inside my Homematic CCU2. It's a 16 GB card that has been in use since... I dunno. It has seen use in some older mobile phone, then after that has been repeatedly wiped, and for years it has served as the card inside the CCU2, storing all historical data. Which isn't much, by itself, but it does mean the CCU2 has been writing to this card for years.

I took it out, and just to be sure did a SLOW reformat on my PC. Afterwards, the card could no longer be read.

SDHC cards are DOOMED to fail

Over the coming days I will find out if the card is the actual culprit, but it made me realize something else. Just like with car parts - or anything else for that matter - we may no longer be able to keep certain technology up and running, because we're running out of spare parts. I checked on Amazon and found only a few reliable (?) suppliers of micro SDHC 16 GB cards left. Which makes sense, because these days 16 GB is laughably small. (I guess I shouldn't mention that I started my adventures in electronics with a Commodore VIC20 with 3.5 kB of RAM.)

These (small) SDHC cards have been a staple for years now. They're everywhere. And they are ageing. And then, suddenly, 10 years later, a device may simply stop because the SDHC memory can no longer be written to... (Do you remember the Tesla MCU1 failure?)

They were never designed to live forever.

Here's the card that died in my CCU2:

Yes, (micro) SDHC cards age. More about that here and here and here (and I stole the image he used for this page.)

Also note that older equipment may no longer be compatible with newer, larger (micro) SDHC / XDHC cards... They might require an older type of card!

For example, the CCU2 can handle max 16 GB, the Zoom H1N can handle max 32 GB, etcetera.

So, how do you address this as a simple end user? Do I know have to take my essential gear apart to see if they have old memory chips or cards in there, and then order some spares whilst I still can?