Smoke alarm (optical) from #AliExpress failed the smoke test. It feeps loudly when pushing the test button, but when held into some nice fire smoke, it does exactly nothing, despite patience.
So always test with a real life scenario. The test button only checks the batteries and the beeper are working, not the actual sensor.
I sent them a nice video and expect a refund. This isn't because it's from China, the same can happen with any.
Got refund, left 1-star warning and did the obvious, crack the thing open.
Test button works, status LED flashes and yet, never mind smoke, even shoving some tin foil inside the detector causes no alarm.
It has what looks like an IR LED and a photo diode, but the LED isn't lit. It's not even powered. Great battery life, I'm sure.
This is a complete fake that can never work. 1000+ sold, proclaims the listing. That's a lot of potentially burning to your death.
Heh, apparently even the Atlanta fire department didn't test theirs, before distributing 18500(!) of them: https://www.cpsc.gov/Newsroom/News-Releases/2011/CPSC-Alert-Counterfeit-Smoke-Alarms-Distributed-in-Atlanta
I guess they trusted in the UL label, which of course counterfeiters definitely would never fake.
@yngmar Wow, that's bad!