Something is slightly wrong when you get home. The bathroom door is open and you close it out of habit. A chair is at an angle you would not leave it at. The flat smells faintly of someone else. Nothing is missing, so there is nothing to report, and you spend the evening trying to decide whether you are remembering the morning correctly. That question has an answer, and it costs about eight cents a day to have it.
Search this question anywhere and the answers assume a break-in, which is why the advice is always alarms, deadbolts and insurance. In a rented flat that is almost never who it is. It is maintenance, arriving to look at the boiler with a notice that was posted after the visit. It is the letting agent showing the place to the next tenant. It is a cleaner, a neighbour with a spare key, a roommate's friend, a landlord who considers the notice period a formality, or an ex who never gave the key back.
None of that is a crime scene, and that is exactly the problem. There is nothing to call anyone about. There is only a suspicion you cannot prove and cannot stop having, and the next time you leave the flat you take it with you.
What people in that position keep asking for is small and specific: not security, not footage, just a record of whether the door opened while nobody was home.
The standard advice fails on the same three points every time.
AI Vision Monitor uses a phone you already have as the eye, and a vision AI model reads what the camera sees and answers a question you typed in your own words. There is no live feed for anyone to watch and no archive to scroll. What arrives is a message, with a timestamp, only when your sentence comes true:
Because the model reads the picture instead of counting changed pixels, it can be told what to ignore. "Anyone other than a cat" is a sentence a motion sensor cannot be given, and it is the difference between an alert that means something and an alert you learn to swipe away.
The alert is the whole product here. It arrives as a push notification, an email, or a message into Telegram or Discord, and it carries the frame that triggered it. Ten seconds later you know that a person was in your hallway at 11:40 on a Tuesday, and the question that had been sitting in the back of your head all week is closed.
That timestamp is worth more than it looks. Until you have one, a conversation about unannounced entry is your memory against somebody else's, and that is a conversation you lose. With one, a single polite message saying that entry was recorded at 11:40 and that you would like notice next time usually ends the behaviour without anything escalating, because the other side now knows the visits are being logged.
| Option | Cost | Landlord involved? | What you end up with |
|---|---|---|---|
| Hair across the door, thread on the handle | Free | No | A yes or no, with no time and no detail, and it fails if the door is opened carefully |
| Doorbell camera | Device plus a plan for history | Usually yes, it is fixed to the building | Who reached the outside of the door, not who came in or when they left |
| Indoor cam with motion alerts | Device plus a plan | No | Dozens of alerts a day, most of them the cat, and clips to scroll |
| Smart lock with an entry log | Lock plus fitting | Yes, it is a change to the door | A log of keys used, and nothing about a key you do not know exists |
| AI Vision Monitor on a spare phone | Free credits to start, no subscription | No, nothing is installed | A timestamped message describing what was in the room, only when it was |
A check every five minutes across a nine-hour day is 108 checks. On a light model at 0.5 credits per check that is 54 credits, about 0.08 euro for the whole day. Running it only on the days you are actually out, which is the sensible way to use it, comes to a couple of euro a month on the 2.99 euro starter pack.
Set it to check only when it detects movement and an empty flat costs close to nothing, because nothing gets analysed until something moves. New users get 50 free credits, no card required, which is enough to run this for several days and find out whether the answer is yes before you pay anything.
Get it on Google Play Download on the App Store
It looks at the scene on an interval, it does not record continuously. Somebody who is in and out between two checks can be missed, which is the main reason to use the movement trigger rather than a long fixed interval if the entry is the whole point. There is no archive to scroll back through either, by design, so what you keep is the alert and the frame that caused it.
It sees one framing of one room, so it knows nothing about a room it is not pointed at. It needs mains power and a working internet connection, because the analysis runs on a server, which means a power cut or a router problem stops the checks. It describes people, it does not identify them, and it does not do face recognition. A dark frame is harder for the AI to read than a lit one, exactly as it is for a person.
And the rules matter more here than in most uses of a camera. Recording inside your own home is treated very differently from recording a communal stairwell, a neighbour's door or another tenant's room, and the difference is not a detail. Point it at your own space. If you share the flat, tell the people you live with rather than finding out later how they feel about it. Audio recording in particular is restricted in many places even where video is not. None of this page is legal advice, and if the situation is serious enough that you are thinking about the legal side, a local tenants' advice service will know your rules better than any app maker does.
Do I need a SIM card in the old phone?
No. Wifi and a charger are enough. A handset with no number and no plan works perfectly well as a camera.
Can I check on it from my desk without waiting for an alert?
You can see the latest captured frame from your own phone or from a browser at app.aicameras.win. It is a snapshot rather than a live video stream, which is what makes it cheap to run and also what keeps it from being something anyone can sit and watch.
What if I already have a wifi camera?
A wifi, RTSP or USB camera can be connected through the free companion app for a Windows or Linux computer, so you can keep the hardware and put plain-language checks on top of it.
Will it alert me for my own cat, or the robot vacuum?
Not if you say so. "Anyone other than a cat" and "a person, not the vacuum" are both things you can write in the sentence, and the model reads the scene rather than detecting movement, so it can act on the distinction.
Can it make a noise when someone comes in?
Yes. The phone acting as the camera can react on the spot with a sound or its flashlight, which is occasionally useful, though for this particular situation a silent alert to your phone is usually the better choice. Someone who knows they were recorded behaves differently from someone who does not know yet.
Is this going to make me more paranoid?
It tends to do the opposite, which is the honest reason to set it up. The thing that wears people down is not the entry, it is the not knowing, and the loop of relitigating your own memory of how you left the room. An empty inbox at the end of the day settles it.