You know what’s gonna surprise a lot of people, and surprised me?

[elizafox@social.treehouse.systems]

You know what’s gonna surprise a lot of people, and surprised me?

The biggest source of BOM cost isn’t sensors (excluding the SPS30 and kinda the SCD40)

The biggest source of BOM isn’t the compute module with the ESP32

No, the biggest source of BOM is… the power module.

Turns out, unless you’re handling tiny amounts of it, power ain’t cheap on a PCB.

eFuse, USB-PD, thick copper, etc.

I understand why GOOD USB-C power bricks are so expensive now.

It isn’t because manufacturers wanna gouge you (mostly). It’s because it just… costs a lot to get components rated for a lot of power, costs a lot to get PCBs rated for that power (thick copper, 4-6 layers, etc.). It costs a lot to make them small enough where they don’t eat your outlet like an old school wall wart.

[elizafox@social.treehouse.systems]

I’ll never trust cheap power bricks again after seeing what goes into them.

Amazon doesn’t have your safety or interests in mind.

They’re counting on the fact when your house burns down, you won’t remember it was something they sold.

They’re counting on “this thing will break or go flaky before it gets to the point it burns down your house.” They’re counting on “it will PROBABLY fail open.”

They’re counting on “they’ll get a light zap and probably won’t die if the grounding clearance turns out to be aspirational.”

They’re counting on “well, a surge is VERY unlikely and they SHOULD use a surge protector.” (SURGE PROTECTORS ARE NOT ISOLATION BTW)

They’re probably right.

But “probably” doesn’t mean “always.” Just means you’re playing Russian Roulette with 9999 empty chambers and one loaded one.

And the times it does burn someone’s house down or torch their living room, it’s easy to blame the user.

[cheappontoon@beige.party]

@Elizafox
AMAZON and other marketplaces are also counting on the FTC bureau of consumer protection to not maintain a database that any rudimentary AI program could use to link a list of fires with a list of products. Or make transparent any consumer complaints or fire stories submitted by fire investigators that could be linked with products or vendors.