>- IoT sensors are a thing, whether the "average person" needs them or not. Think remote weather stations, car counting cameras, GPS trackers...

Something tells me that your average municipal government or enterprise isn't going to want a hodgepodge fleet of phones as IOT sensors. Most of the applications you describe don't even need to the phone to be reprogrammed. There's a dozen apps that allow your phone to be repurposed as cameras or GPS trackers today, what's holding back their adoption?

>- "Smart thermostats" exist, surely you could just copy whatever they're doing with ease. And let's not limit ourselves to DIY here.

Yeah but how much is this custom hardware going to cost, especially when you don't have economies of scale? You can get a sleek looking smart thermostat for $150-200. Most people will take that over a tangled mess of wires that a DIY solution is going to look like https://en.wikipedia.org/wiki/File:Ahmed_Mohamed_Clock_by_Ir...

>- Every block of flats I've been in here has had an intercom system, some even have video transmission. Sounds like a job for old phone hardware, no?

So you're going to be gluing a phone next to your door? Sounds like a great way to lose an old phone.

>And just to repeat, I don't want regular people to start making these things out of old phones en masse, I want businesses to have that opportunity. You're arguing against a strawman.

No, you're arguing against a strawman. If you read my initial comment you'd see it states in no uncertain terms that I'm skeptical of the argument that it'll meaningfully reduce e-waste, not that there's going to be exactly zero people repurposing their phones.

>By nodes I meant, say robotic applications, simple room surveillance camera, baby monitor,audio streaming, multimedia/tv remote control, where a rpi/custom hw could be perfectly be replaced by an old phone, since it comes with imu, cameras, audio, touchscreen, wifi, storage, etc.

For the family that has a techie willing to jump through a dozen hoops to set those up, sure it might mitigate some e-waste. However I doubt that's applicable to most or even 10% of people. Moreover I don't see how an unlocked OS is necessary for most of the applications you mentioned. Why do you need an unlocked bootloader to turn a phone into a camera/baby monitor? Aren't there a dozen apps that basically serves that purpose? Finally, as the saying goes, "[insert OSS project] is only free if you don't value your time". Sure, you can spend an entire weekend turning your old phones into cameras, installing frigate on a docker container somewhere, and adding a coral TPU to do object recognition. Or you can pay $50 for a 2-pack of wyze cameras which have cloud connectivity and object recognition out of the box, and is in a far better form factor than a smartphone.

The point isn't that exactly zero phones will be diverted from landfill, just that approximately zero phones will be.

The iPhone 13 mini is a faceID device - but I’m holding onto it until the bitter end. But we’ve been using iPhone SE as company phones until they were discontinued- the devices are perfectly usable for all basic use cases.

The internet means it's easy to find "lots" of people for anything. Excluding yourself how many iPhones do you see in the wild have a home button? I'd estimate less than 1 in 20, or 5%. If less than 5% of people are keeping their phones while they're in support, how much e-waste can you possibly divert by allowing third party OS?

>You don’t know that because the regulations have never existed. Please try to refrain from unscientific thinking

You're accusing me of "unscientific thinking", but you're basically making an argument from ignorance? You haven't provided any rebuttals to my argument, and you're basically arguing "we haven't tried so if you try to argue against it you're WRONG".

Note $2 on aliexpress gets you a fully assembled module. If you're trying to repurpose chips after desoldering you still need to sort, test, and resolder them.