Use your phone as a baby monitor

Most of what a baby monitor does, two phones already do: one has a microphone and sits in the room, the other makes a noise when you are needed. What follows is which devices to use for which half, the four things a phone does worse than a dedicated unit, and how to set it up without installing anything.

What you need

Two devices with a microphone, a charger for the one that stays with the baby, and a network on both. Neither device has to be new, and they do not have to match.

The two halves ask for very different things, which is the easy thing to get the wrong way round on the first night. The device by the cot is occupied for the whole evening: screen on, plugged in, in a room you are not in. The device you keep is barely used at all, since it only has to make a noise — so your everyday phone is the right one for that end, and something you can spare is the right one for the cot.

Can you use two phones as a baby monitor?

Yes, and it is the obvious pair, because it is the one you always have. One phone stays with the baby and listens; the other alerts you. Plug the first one in, put it somewhere the microphone is not muffled by a blanket, and silence the notifications on it rather than on the phone you keep.

The one thing to settle before bedtime is whether you can leave the room, or even the building. Some tools only connect two devices on the same Wi-Fi, which is fine at home and useless in a hotel or a rented flat. Ones that connect over the internet let one phone sit on the house Wi-Fi while the other is on mobile data.

Can I use my laptop as a baby monitor?

Yes, and on the listening side a laptop is often better than a phone. It is already open on the kitchen table, already plugged in, and a screen you can read from across the room beats one in your pocket. It also leaves both phones free, which on a night with two adults and one baby matters more than it sounds.

A laptop works by the cot too, as long as you can put it somewhere safe and stop it suspending when the lid closes. A tablet is the easier object in that spot: it stands up on its own and nobody needs it back.

This is where the apps run out. The ones in the App Store and Play Store are phones and tablets only, so a MacBook and an iPhone cannot be the two halves of the same monitor however much you would like them to be. A monitor that runs in a browser has no such rule: every combination is the same page open twice.

Can you turn an old phone into a baby monitor?

The retired handset in the drawer is the obvious candidate for the cot end, and it is a good one. It costs nothing, nobody needs it back, and being plugged in and warm for three hours does it no harm.

Check one thing first: most old phones have no SIM card in them, so they can only work where there is a Wi-Fi network you can join. At home or at the grandparents' that is usually fine. On a campsite, in a car park, or in a rented flat whose router you cannot log into, it is not, and the phones with data in them are the ones you carry every day. Test the old one on the actual network before the actual evening.

Does it work between an iPhone and an Android?

One of each is an ordinary household, and it is where a lot of monitor apps stop: they need the same app at both ends, so an iPhone by the cot and an Android in your pocket is simply not on offer. Check that before you pay for anything.

Anything running in the browser sidesteps the question, since both halves are the same web page. The brand, the operating system and the app store stop being part of the setup.

Is it free?

Usually free to install, which is not the same thing. The common shape in the stores is a free tier that listens, with the video, the recording, the second listening device or the alerts kept behind a subscription — and you tend to meet the paywall at half past seven with a baby already asleep. The browser-based ones are more often free outright, since there is nothing to sell you in a store.

NapLink is free today, with no account and no card. What a paid side would look like later, if the relay ever costs real money, is written down on the pricing page: hours bought once, never a subscription.

Does it work without Wi-Fi?

Two different questions hide behind that one, and they have opposite answers.

Without a shared Wi-Fi, yes: a monitor that connects its two devices over the internet does not care that one is on the house network and the other on mobile data. Sound alone costs a small fraction of what video costs, so an evening of listening is cheap on a data plan.

Without any network, no. No phone-based monitor of any kind works with two devices that cannot reach the internet, and no amount of setup changes that. If you are somewhere with no signal at all, a dedicated DECT unit on its own frequency is the answer, and it is genuinely hard to beat there.

Where a phone is worse than a dedicated monitor

• It cannot see in the dark. A baby monitor has infrared and shows you a lit picture of an unlit room. A phone camera sees a black rectangle, and the only way to change that is to light the room, which rather defeats the purpose.
• It is a general-purpose device doing one job. A call, a low battery, an operating system update at two in the morning — none of these can happen to a unit whose only trick is a microphone.
• It has nowhere to stand. Dedicated cameras clamp to a cot or screw to a wall at the right angle. A phone leans on a pile of books.
• It needs a network, and networks fail politely. A DECT pair on its own frequency has nothing to fall out of. Anything over the internet does, which makes it worth knowing whether your tool actually tells you when the link has gone.

A phone is still the right monitor for the night you do not have the other one, which is usually the night someone goes looking for this.

Before you rely on it for a whole evening

• Try it at home first, in the room and on the network you will actually use.
• Plug the device by the cot into power, and check its screen stays awake.
• Silence the notifications on that device, not on the one you keep.
• Walk to the furthest point you intend to sit at and check the sound is still there.
• Agree out loud who is listening. Two adults each assuming the other one has an ear on it is the oldest failure of the lot, and no device fixes it.

The same evening away from home, where the network is one you have never used before, is its own list: a baby monitor away from home.

Where NapLink comes in

NapLink is a baby monitor that runs in the browser, so there is nothing to install and no account to make. You open it on the device that stays with the baby, scan the code with the one you keep, and it is listening. Any two devices, in any combination: an iPhone by the cot and an Android in your pocket, a phone in the bedroom and a laptop on the kitchen table.

The two devices connect to each other over the internet, so they do not need the same Wi-Fi and one of them can be on mobile data. The alert reaches a locked phone with the page closed, rather than only making a noise in an open tab. And when the link drops, both ends say so, because a quiet screen must never mean two things at once. It is free.

NapLink is not a medical or safety device. It depends on two devices, their batteries, their browsers and a network, any of which can fail without warning. Never rely on it as your only means of supervising a child.