Is the Sense-U Smart Sock accurate?

I couldn’t get a signal to hold long enough to judge; even on a well-perfused adult thumb it read for only 30 to 40 seconds before dropping out. On my son’s foot it never got an oxygen reading at all.

Does the Sense-U have an oxygen alarm?

No. The app lets you set heart-rate alert thresholds, but the oxygen screen has no alerts section, so there’s no low-oxygen level to alarm on.

Will it alert me if my baby stops breathing?

It doesn’t monitor breathing, it has no oxygen alarm at all, and its heart-rate alarm didn’t fire in my own test. Treat it as a wellness tracker, not a safety device, which is what the maker’s own disclaimer says. If SIDS is the worry, I wrote an honest piece on whether baby monitors prevent SIDS.

Does it work without keeping the app open?

Not reliably. Sense-U’s own FAQ says the app must run in the foreground and, on Android, keep Location on, or it can’t stay connected.

Is the Sense-U better than the Owlet?

No, not in my testing. The Owlet Dream Sock held a signal all night, tracked within about 2% of a hospital monitor, and has a real oxygen alarm — the things the Sense-U couldn’t do.