Ask Hackaday: Preserving Electronic Devices

Conventional wisdom holds that we no longer make things to last for the long haul, and that we live in a disposable world. It’s understandable — after all, most of us have a cell phone in our pocket that’s no more than a year or two old, and it’s often cheaper to buy a new printer than replace the ink cartridges. But most of that disposability is driven by market forces, like new software that makes a device obsolete long before it breaks down, or the razor and blades model that makes you pay through the nose for ink. It turns out that most electronic devices are actually pretty well engineered, and as long as they’re not abused can still be operating decades down the road.

But what happens when you want to put an electromechanical device away and preserve it for a rainy day? What can you do to make sure the device will operate again a few years down the road? Are there steps one can take beyond the typical “keep it in a cool, dry place” advice? In short, how do you preserve electronic devices?

The Problem

I’ll admit that there aren’t a huge number of devices that are worth the extra effort that would go into storing them for future use. But I have a specific piece of gear that I’m looking to put into storage: my daughter’s old insulin pump. We recently started having some trouble with her pump, an Animas Ping that has been a solid performer for over three years. They seemed to be software issues, minor annoyances that the manufacturer couldn’t seem to resolve despite replacing the unit outright twice. We decided to try for a pump from another manufacturer through our health insurance, and after a flurry of letters and phone calls, a new pump was approved.

The device in question: her old insulin pump. Note the time — the RTC died within a week without the battery.

But now I’m left with a conundrum: what to do with the old pump? Hacker me says, “Teardown!” There’s certainly something to be said for what I’d learn by looking under the hood, but responsible adult me sees this as an opportunity to have a backup for the new pump. As we learned with the first pump, these devices are far from perfect. Diabetics using a pump have to keep a backup supply of needles and syringes ready to deliver insulin the old-fashioned way in case the pump fails. But it’s a difficult and traumatic transition, especially for a kid, and having a pump around that could be put back into service quickly would be great for our peace of mind.

With that in mind, I’m left with the question of how best to preserve the old pump in top operating condition. If it were something as simple as an obsolete cell phone, you could reasonably expect to just toss it in a drawer and be able to boot it up again in a couple of years after charging the battery. But this pump is an electromechanical device with a finely calibrated syringe pump driven by a tiny but powerful gear motor. There are moving parts in addition to the electronics, all of which need to work together.

There’s also the wrinkle that the pump does not have a rechargeable battery — it runs on a single lithium AA battery. There appears to be either a supercapacitor or a small rechargeable internal battery to maintain the real-time clock, which I assume is topped off from the main battery. There’s also the question of how the pump’s setting are maintained — I assume there’s flash memory of some sort in there, in addition to the pump’s firmware.

My Ideas

My basic approach to preserving this pump will be to store it powered down. Leaving batteries in devices for extended periods is never a good idea, and a leaking battery is likely to be fatal to the pump. Plus, this device expects to be doing something when it’s powered up, and if there’s no insulin to deliver, it starts to whine. I’ve already left the battery out for a week and seen that only the real-time clock resets; all the other settings are preserved. I’m going to slowly increase the time off-battery to a month and see what sort of issues arise, if any.

If I can get to a month unpowered, I’ll put a reminder in my calendar to pull the pump out of storage and give it a little exercise. My experience with electromechanical systems like 35-mm cameras is “use it or lose it” — mechanisms need to move once in a while to keep everything working. So maybe I’ll put the battery in once a month and give the pump a little workout, moving the plunger back and forth a few times to make sure everything is still working.

Your Turn

Those are my ideas for now. But here’s where you get to pitch in. How would you put a device like this aside for a rainy day? I realize I may be going overboard here, but keeping in mind that this is a vital piece of medical equipment, a little extra care is probably prudent.

Or perhaps you think I haven’t gone far enough. Either way, sound off in the comments below. And if you have any experience stashing gear for the long haul, by all means share your story. I have a feeling that there might be some interesting tales out there about not only the hows but the whys: what would make you go to the effort to preserve something electronic?

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