Everything with a battery should have an off switch

Can you tell whether you work in a product design company, or an engineering company?

Does that come from clients?

I used the same 3-in-1 latch circuit for power on/off, pairing, and software power off for 12 years.

A good enhancement mode NMOS FET can be as good as a physical switch at low voltages.

If you really need nano-amp level leakage current AND very low drop, you can consider turning to beefy depletion mode devices, which gate the user will discharge with the button press. A nice benefit is that you can directly sense the button press with an MCU.

I once even did a bluetooth mouse with this "hardware" switch, and a graceful shutdown: we sense voltage on the buck capacitor, and detect when the battery disconnect triggers.

The few microfarads in the capacitor are enough to send the last update with the 0% battery level, and a disconnect command.

it doesnt even have to be a mitutoyo to get you down to 0.01mm precision, i got mine for about 40euros. Using equipment i had access to at work i checked that rating and indeed: the tool i got is good for measuring at that scale, and you really dont need any electronics.

Usually you can pay the vendor to calibrate the tool for a couple bucks more.

of course digital ones are much, much easier to read, but you only really feel that convenience when having to measure hundreds of items quickly to sort them into a tray or something...

And in the end, usually a Nonius type caliper is good enough anyways, and skilled users can read those to up to 0.02mm... and thats already pretty good and most of the time: good enough

and in case you do need to know the length of something down to a micron, there are other tools for that with less sources for measuring errors

so yeah: mechanical calipers rock and: you dont have to always get the brand things to get what you need

> by spinning a dial

When we moved into our current house, it had a microwave like that. When we replaced it, my primary requirements were 1. multiple fan speeds, and 2. a nice, simple touch pad for entering the time; preferably one where you didn't need to press a button before starting to enter the cooking time.

The dial thing is... infuriating. It never once found a situation where it made using the device better, and in most situations it made it worse.

You might be able to remove the “buzzer” or speaker in the device.

That's such a godawful book. In my view it epitomizes everything that is wrong with design today. And the worst part is that comments like these make it come off as the go-to reference to actually solving these problems.

The reasons it's the worst design guidance out there is that it teaches: 1) that engineers should NOT be entrusted/involved with user design. 2) to conceptualize users as blissful idiots. 3) that obscuring errors in a system is actually a good thing.

All of these are things that I see the lasting effects of in products I use in every day. Don't get me wrong, I bought this with the best of intentions. It was the highest rated design book on Amazon on the topic. Reading through was an extremely painful exercise in essentially coming to realize that everything I see broken in the engineering teams I work with and products I use is actually codified in words.

Take this excerpt as an example -- p. 65: "Eliminate all error messages from electronic and computer systems. Instead, provide help and insight."

Are you f'ing kidding me? You cannot seriously think this is right. For the longest of time I wondered why I hated using Apple products. It turns out Norman was schooled at Apple and they absolutely practice this teaching. I bought an early-day iPod touch circa 2007 and proceeded on to loading all my music on it. A few upgrades later, some albums disappeared without any error. I searched and searched and searched, trying to describe my problem in a number of different ways on Google to see what I could find. And all I could find were semi-answers. But you know what? If it had actually displayed "error 0xFHJAD1234" when failing during the upgrade, I could've actually google that. And I'll spare you the story of what I had to do when the family Mac's HDD failed ...

So this is what we actually get, devices that SILENTLY fail, designed for people who are assumed not to know what they're doing and who likely do NOT have any technically-literate person around them that could assist them if they could in fact identify the problem.

Worse, this philosophy probably hints at a level of intellectual ignorance/arrogance that is quite fascinating. You see, in my line of work I have to be able to walk engineers I work with from the gate-level silicon all the way up to cloud and AI. Without any false modesty, I think I have a fairly good idea of how modern computer architecture works. Yet, I will be the first to tell you that I have no idea how any of these systems work in full. In fact, no one does. Not the best of kernel developers nor the best of chip designers. To claim that you can somehow inventory every possible problem in a computerized system and then provide a graceful exit from that or useful info is either ignorant or arrogant or both. But since you've eliminated engineers from the design loop (see #1 above), no one will tell you you're full of it.

So yeah, no. Do read Norman's book. But look at it as everything you should NOT be doing.