Why your baby monitor doesn’t wake you on silent

Written 27 August 2026 · Android and iPhone · About 6 minutes

You put the phone on silent so a work email at 11pm doesn’t wake the baby. Then the baby cries, and the app that was supposed to wake you says nothing at all. This is not a bug in your phone. It is the phone doing exactly what you told it — and it is why an ordinary notification is the wrong tool for a monitor.

Why a normal notification stays quiet

When you silence a phone, you are not turning the speaker off. You are telling the operating system which categories of interruption you are willing to be disturbed by. Everything else is delivered silently: it arrives, it appears in the shade, and it makes no sound and lights no screen.

That is the correct behaviour for almost everything. A messaging app that could override your silent switch would be a menace, so the platforms make it hard on purpose. The result is that a baby monitor built on ordinary push notifications is indistinguishable from a chat app at 3am — and it loses.

This catches people out because the app looks like it is working. The alert really is being delivered. Open the phone afterwards and there it is in the notification list, timestamped to the exact moment you slept through it.

What actually works on Android

Android exposes the escape hatch through notification channels. A channel can be marked as bypassing Do Not Disturb, but the app only gets that power if you grant it Notification Policy access — a separate permission, in a separate settings screen, that most apps never ask for.

Three things have to line up, and missing any one of them fails silently:

• A high-importance channel that bypasses Do Not Disturb. Importance alone is not enough; the DND bypass is a distinct flag, and setting it requires the permission above.
• Alarm-category audio. Sound has a usage type attached. A notification sound routed as a notification follows the notification volume, which is what you just silenced. Routed as an alarm, it follows the alarm volume — the one that still fires at 6am with the phone on silent.
• A full-screen intent. This is what turns the screen on and puts something in front of the lock screen, the way an incoming call does, instead of a banner nobody is awake to see.

Calmina uses all three. The cry alert sounds on the alarm path rather than the notification path, and if the first alert goes unanswered it escalates to a full-screen alarm over the lock screen. That escalation is built to survive an aggressive battery manager killing the app mid-alert — the case that makes most monitors fail quietly on exactly the phones that need them most.

Deliberately, only crying gets this treatment. Low battery, ordinary room noise and movement alerts are high-priority heads-up notifications and nothing more — they never bypass Do Not Disturb and never take over the screen. An app that pierces silent mode for everything trains you to silence it entirely, which costs you the one alert that mattered.

What actually works on iPhone

iOS has a similar escape hatch and guards it more tightly. Ordinary notifications, including ones marked time-sensitive, respect the silent switch and Focus. The mechanism that does not is Critical Alerts — the same class of interruption used by medical and safety apps. It sounds through silent mode and through Focus, at a volume you set separately.

Two gates stand in front of it. Apple must grant the app the entitlement, which is an application process rather than a checkbox, and then you must approve Critical Alerts on your own device — a separate prompt from the ordinary notifications permission, which you can revoke at any time in Settings.

The other half: staying alive until morning

An alert that would have woken you is no use if the app was frozen before the baby cried. Both platforms aggressively suspend background apps, and some Android manufacturers do considerably more than stock Android does.

• Battery optimisation needs an exemption on the nursery phone, or the monitoring service gets suspended once the screen has been off for a while.
• Manufacturer restrictions are the ones people miss. Several popular Android skins have an extra “autostart” setting and their own per-app battery policy, both separate from Android’s own, and both capable of killing a running monitor overnight.
• The nursery phone should be charging. A monitoring session with the screen dimmed and the microphone live is not a low-power state on any phone.

Test it before you need it

This is the part worth doing tonight, whichever monitor you use. The failure mode is silent by definition, so the only way to know is to provoke it.

1. Put the parent phone in the exact state it will be in overnight — silent, or Do Not Disturb, or whatever bedtime routine you actually use.
2. Lock it and put it down, screen off, where it will sit.
3. Trigger a real alert from the nursery phone. Calmina has a Test the alert screen that fires the genuine alarm path rather than a preview of it; if your monitor has an equivalent, use that rather than trusting a settings toggle.
4. Watch what the parent phone does from across the room. A screen that lights up and an alarm you can hear from another room is a pass. A silent buzz, or nothing at all, means one of the permissions above is not actually granted.

Do it again after any OS update. Permissions survive updates; manufacturer battery settings sometimes do not.

Calmina is not a substitute for direct adult supervision or a medical monitoring device. No monitor can be relied on to detect a medical emergency.