[nickff]

>” How much extra cost does a hard on/off switch add to the bill of materials?”

BoM cost is not the whole story; a physical switch can greatly complicate an assembly, and may require hand-soldered wires. In addition to those cost-related factors, external switches are usually quite ugly, and getting them right can be very challenging, so it’s much easier to just omit them.

[ggm]

I think this is special pleading. At the volume we're discussing a surface mount flow solder on off device is not going to kill the BoM, and could be designed not to be ugly.

It's no different to any other bad design. It could be better.

All phones and computers can be completely powered down. They're hardly ugly switches.

[abofh]

Ermm, most phones and computers cannot be completely powered down. Either by nit-picking (CMOS clocks) or soft-switches (ACPI, soft button power-on), there's always some voltage in the system unless your PSU comes with an actual hard power switch (and even then, again, CMOS).

They consume a lot less power, but leave an 'off' phone in a drawer for a month starting at 100%, it will not be 100% when you 'turn it on'.

[JoeAltmaier]

In low-power mode even those microcontrollers are using just nA (yes that's nano-Amps). Vs 100's of mA in operation. So the battery life goes from hours to what should be decades.

I'm thinking the battery goes dead because of leakage currents through the rest of the circuits, which were probably not designed to the nA standard.

A solid-state Off switch would also need a good silicon device to cut current consumption at the battery. Which also costs something.

[unwind]

I understand and agree, but the use-case is a bit skewed since that's not even true for a bare "naked" battery or cell.

They all self-discharge [1], some chemistries more than others of course but phone batteries certainly do.

[1]: https://en.wikipedia.org/wiki/Self-discharge

[Retric]

Self discharge is easily an order of magnitude slower than the power draw of these devices while seemingly off.

[throw10920]

> I think this is special pleading.

This is an emotional, low-quality response to what is a measured comment actually providing nuance to the discussion.

The parent poster is very clearly not saying that leaving off the power switch leads to a better experience for the consumer - they're just giving legit reasons that a design/marketing team might use to justify doing so. Please don't try to cheapen the knowledge that they provided like this.

[IIsi50MHz]

I took it as "I think the reasons given are not legitimate, and are poor excuses for 'maldesign'.".

Where 'maldesign' is my dad's favourite word for every seeming design flaw or 'unreasonable' limitation. (-:

[m_eiman]

> All phones and computers can be completely powered down. They're hardly ugly switches.

iPhones (and I assume most Androids as well) can't be completely powered off. Neither can Macbooks. In fact, I'd guess that most modern digital things with non-replaceable batteries can't be powered off.

[bombcar]

There’s a specific Dell laptop reset procedure that requires you to open the case and disconnect the battery so you can then press and hold the power button to get it to discharge all residual power. It’s a pain.

[jasonthorsness]

I had to do this a couple of times with a Lenovo that sometimes locked up completely when it went to suspend - battery was highly inaccessible so it was a 30 minute tense process each time - firmware update eventually solved the problem. Not sure what the solution for this is - something like one of those paper clip reset holes?

[maxerickson]

The caliper and kitchen scale already have buttons.

(they would both be shitty without a zero/tare button)

[Tempest1981]

My $20 "Pittsburgh" calipers from Harbor Freight (don't judge) are still on their original batteries, after 6 years. They have a power button, and a separate zero button.

[felixhandte]

They don't actually turn off though. It just turns the display off. They need to continuously sense position since digital calipers measure movement increments rather than absolute position. That's why if you take the battery out and put it back in it will prompt you to re-zero the calipers.

Amusing video explanation: https://www.youtube.com/watch?v=KnDype-j3hk

[maxerickson]

It's not uncommon for them to be designed to require zeroing at each power on.

[bombcar]

Many of these “auto zero” which is why you have to do the scale dance - tap it with your foot to turn it on, wait for it to say zero, then step on.

[maxerickson]

Yeah, my explicit mention of kitchen scales and calipers was intentional, they both become much more useful if the user can choose to zero the readout at any time.

This is less true for a bathroom scale.

[thfuran]

Went not just stand on it while it tares and ignore the negative when you step off?

[majewsky]

All the digital bathroom scales that I've encountered refuse to display negative measurements.

[thfuran]

Well my kitchen scale does. Though I don't know many people who weigh less than five pounds.

[newsclues]

And on off switches can result in a call to support ($) or negative reviews when idiots can’t turn it on.

[SilasX]

In contrast to users who look for one but don't find it, who don't call support?

[kuu]

Seriously? Is 2022 and we didn't solve the switch button? I'm sorry but I just don't believe you.

[foldr]

It's weird but true. Adding physical switches to a device can be one of the most complex design elements. It complicates both the layout of the PCB and the design of the case. Finding a suitable switch is also a real pain, as parametric searches for switches don't work particularly well.

[Nextgrid]

We did, but maybe not cheaply enough. If they can save a few cents by passing on the cost to you (in the form of more battery usage) they will do so as long as the market (or regulatory environment) doesn't mind.