Door Bell for rental apartment

BUNKER HILL SECURITY Wireless Security Alert System (under $20 USD) The wireless detector is IR (heat) movement. When I had it at my house with a walkway facing the front door, branches shaken by wind didn’t set it off unless there was sunshine coming through branches being shaken by wind. Once in the apartment, our doorways have a entrance structure. So, I faced it twards my door. Anyone stepping up to the door is detected. There is a two level loud alarm inside. A friend of mine has one on a small farmhouse. The transmitter makes it around 400 m. (That should cover almost any apartment, unless you live in Texas!). Both units require batteries.

I have a $10 battery powered wireless doorbell from Home Zone Security.
The stick-on button has been exposed to very high wind, rain, snow and sun with no problems.
I can lay the alarm anywhere I want.

Yeah, similar problem for me…

I use a simple wireless doorbell (see example pic, mine is a bit older). The push button uses a CR button battery that seems to work forever (12y and counting), and I have plugged a bunch of ringing receptors (at full volume) in sockets all over my house (and one in the garden- these wireless signals carry very far). I also chose a melody that uses frequencies I hear the best, at the highest volume, and one of the bells sits next to my TV and also flashes strobe lights when it rings.
(The new doorbell button sits actually inside my house, and the old outside doorbell just closes a circuit that activates the new one- I rewired a few things. But if you are in a rental you may simply have to tape over the old doorbell).

In parallel I have a doorcam that permanently sends its image to an old iPad that I have on a stand in my living room. That oldish doorcam is wired (for power), but newer ones can also be powered by a small solar panel, depending on where they sit.

As a fun, side note, I also disassembled another doorbell button and mounted it under my mailbox so that when the flap or little door moves just a single home doorbell rings (with a different melody, ofc)… This was done mostly to reduce the risk of theft of packages.