Your Phone's Screen Is Cracked and the Camera Still Works: Setting Up an Old-Phone Security Camera You Cannot Touch

Twice in this blog I have told people that a cracked screen does not matter.

In the shop-monitoring guide it is item one on the shopping list: "An old Android phone. Anything you stopped using. A cracked screen is fine — you will not be looking at it." In the pet-camera guide I said it again: "If the screen is cracked, that doesn't matter; the screen will be off."

Both sentences are true about the ten months the phone spends on a shelf. Neither is true about the ten minutes before that.

For those ten minutes you have to unlock the phone, join Wi-Fi, install something, answer four permission dialogs and press start — and every one of those is a touch event, on the exact component that breaks when a phone hits a floor. "You will not be looking at it" answers the display. It does not answer the digitizer. I skipped that, twice, and this is the missing half.

The good news: Android has had a documented answer since 2011, it costs about a dollar, and it does not involve a computer.

Can you use a phone with a broken screen as a security camera?

Short answer: Usually yes. A camera phone does not need its display after setup — but setup itself needs input. If the picture is broken and touch still responds, you can drive it as-is. If touch is dead and the picture is fine, a USB mouse plugged in through a $1 OTG adapter gives you a pointer, with no computer, no drivers and no developer settings. If both are dead, you need a PC — and whether that works depends on a decision you had to make before the screen broke.

How do you set up an Android phone when the touchscreen does not work?

Short answer: Connect a wired USB mouse through a USB-OTG adapter. Android has supported USB host mode since Android 3.1 (API level 12), mice are explicitly among the supported device classes, and Google's own documentation says "No special configuration or driver is needed, in most cases." A pointer appears on screen and you can point, select, drag, scroll and hover through the entire setup. This works on a locked phone, so you can enter the PIN with it too.

The screen is two parts, and they die separately

This decides everything else, and almost nobody separates them.

The panel you look at and the layer that senses your finger are different components stacked on top of each other. A drop can kill one, the other, or both. The spider-web of cracks tells you the glass is broken; it tells you nothing about whether touch still works underneath it.

So before buying anything, find out which failure you have:

• Picture fine, nothing responds to touch — dead digitizer. Common with liquid damage and with "the bottom third is dead" phones.
• Screen black, dim, or a mess of lines, but the phone vibrates and rings — dying display, working touch.
• Nothing at all — either both, or the phone genuinely is dead.

Quick test for the middle case: plug in a charger and tap where the unlock button would be. Haptic feedback in the right places means touch is alive.

Case 1: cracked glass, touch still works

Nothing to solve. Set it up normally, put it where it belongs, and let the display go off for good. This is the case both of my earlier articles were quietly assuming, and it is genuinely the majority of drawer phones — cosmetic damage, working hardware. Write down the Wi-Fi password and the screen-lock PIN while you still can; once the phone is on a wall, a forgotten PIN is a real problem.

Case 2: touch is dead, the picture is fine — use a mouse

This is the fix that deserves to be better known, because it is old, official and cheap.

Android's USB support has two directions. In host mode the phone acts as the host and powers the bus, and the documentation lists what you can plug into it: "Examples of devices include digital cameras, keyboards, mice, and game controllers." That has been in the platform since Android 3.1 — so essentially any phone you are likely to be repurposing already has it.

The 3.1 release notes are explicit about what this feels like to use. On setup: "No special configuration or driver is needed, in most cases." On pointers:

"For pointing devices, the platform supports most types of mouse with a single button and optionally a scroll wheel, as well as similar devices such as trackballs. When these are connected, users can interact with the UI using point, select, drag, scroll, hover, and other standard actions."

Point, select, drag, scroll, hover — every gesture a setup wizard asks for.

What you need: a USB-OTG adapter matching the phone's port (micro-USB or USB-C), and any wired USB mouse. The adapter is usually the cheapest accessory on the shelf. Choose wired over Bluetooth — pairing is itself a touch-dependent task on a phone you cannot touch.

The 60-second test: plug the adapter into the phone, the mouse into the adapter, and move the mouse. If a small arrow appears, you are done deciding; everything from here is clicking. If nothing appears after ten seconds, try a different adapter before giving up — the adapters are the flaky part.

The honest caveat, in Google's own words: "Support for USB host and accessory modes are ultimately dependant on the device's hardware, regardless of platform level." The platform supporting it does not oblige the manufacturer to wire it up. Budget and entry-level models are the most likely to have left it out. There is no way to know from the spec sheet — you test it.

If it works, the mouse solves the whole problem, lock screen included: a pointer clicks PIN pad digits exactly like a finger.

Case 3: both are dead — and the trap in the obvious answer

Search this problem and you will be told to use scrcpy, a free and open-source tool from Genymobile that mirrors an Android screen to a computer and lets you control it with your own keyboard and mouse. It is excellent, it works from Android 5.0 (API 21) upward, and it is exactly the right shape of tool.

It also has a requirement stated plainly in its README: "Make sure you enabled USB debugging on your device(s)." Enabling USB debugging requires tapping through Settings. On the phone. Which is the thing you cannot do.

And it goes a layer deeper: even with debugging already on, the first connection from a new computer triggers an on-device confirmation. scrcpy's FAQ describes it directly — "When connecting, a popup should open on the device. You must authorize USB debugging." A popup you must approve, on a screen that shows you nothing.

So the fork is: if debugging was already on and this computer was already authorized, you are fine — mirror the screen, set the camera up with your desktop mouse, unplug. If it wasn't, the standard advice does not apply to you, however often it is repeated.

One path remains, and it is a nice piece of symmetry. scrcpy has an OTG mode that "allows to control the device using AOA keyboard, mouse and gamepad, without using adb at all (so USB debugging is not necessary)." Your computer stops being a debugger and starts pretending to be a plugged-in mouse. No debugging, no authorization popup.

The catch is the very next sentence: "In this mode, video and audio are disabled."

Control without a picture. You are moving a pointer around a screen you cannot see — workable only if you know the menus by muscle memory and have an identical handset to practise on. I would rather say that than pretend it is a fix.

Notice what the two working paths have in common. In Case 2 the phone is the USB host and the mouse is the peripheral. In Case 3 the roles invert: the computer is the host, the phone the accessory. Same port, opposite direction, and which one you need is decided by which half of the screen survived.

The order to do things in

With limited or borrowed input, do the fiddly things first, while you still have a pointer:

1. Disable the screen lock, so a reboot after a power cut doesn't lock you out of a phone you can't type on.
2. Join the Wi-Fi. Typing a WPA2 password is the hardest input task in the process.
3. Install the camera app and grant every permission. Permission dialogs are modal — an unanswered one blocks everything behind it.
4. Turn off automatic updates and set display sleep to the shortest interval.
5. Start the camera and confirm the stream from another device — any phone or laptop with a browser on the same network.
6. Only then mount it and put the mouse away.

Step 5 matters most: it is the moment the phone's own screen stops being part of the system. From then on the interface is a browser window on a device that works.

What the documentation does not tell you

Six real gaps, stated rather than guessed at:

1. Which phones actually implement USB host mode. The docs say it depends on the hardware, and name no models, no list, and no way to check short of trying it.
2. Whether a mouse works on the very first boot. The out-of-box wizard on a factory-reset phone runs before most of the system does; Google's mouse documentation describes a phone already in use.
3. Input on an encrypted device before first unlock. A just-rebooted phone wants its PIN before almost anything works, and none of these pages address that window.
4. Power draw. The mouse runs off the phone's battery through the adapter, and no published figure says what that costs a phone with a worn battery.
5. The age of the source. The clearest description of Android mouse support sits on the Android 3.1 highlights page — last updated 2024-05-20, describing a 2011 release. It has never been rewritten for the modern platform, which is why the capability is so widely forgotten.
6. Phantom touches. A cracked digitizer can register presses nobody made, and a phantom tap can dismiss a dialog or stop a recording. Nothing documents living with a partially broken input device.

The claim, corrected

"A cracked screen is fine — you will not be looking at it" is right, and I stand by it. It is just incomplete. The full version:

A cracked screen is fine once the phone is running. Getting it running needs input, not a display — and in the common case input costs about a dollar and no computer at all.

That distinction matters because of who it affects. The phones most likely to be sitting unused with a smashed screen are exactly the ones being reused as cameras: three-to-six-year-old budget handsets, in households where a screen replacement costs more than the phone is worth. Telling that reader "the screen doesn't matter" and omitting the setup problem sends them away thinking the phone is unusable, when a mouse would have fixed it in five minutes.

If your phone passes the pointer test, it is a camera. Go and check.

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Background Camera RemoteStream records with the screen off, stores video locally on the phone, and serves a live view over your own network to any browser — so once it is set up, the phone's own screen is not part of how you use it. Google Play · superfunicular.com

Related reading: How to Watch Your Shop With an Old Android Phone (where the cracked-screen claim first appeared) · Monitor Your Dog While You're at Work for Free · Why Does My Android Camera Stop Recording When the Screen Turns Off? · How to Use an Old Phone as a Security Camera Without a Wi-Fi Router

Sources: USB host and accessory overview (Android Developers, last updated 2026-02-26) · Honeycomb MR1 platform highlights (Android Developers, last updated 2024-05-20) · scrcpy README, FAQ and OTG documentation (Genymobile, Apache 2.0)