not sure what forum is the right one for this question… I’m looking for a “sensor” that can tell me whether my smartphone is exactly at a given place, or, more precise, get notified if it leaves that place.
No fancy bluetooth triangulation, but - hopefully easier? - an actual hardware sensor. I would physically place my smartphone on/in/next to this sensor and would like to get notified if it is removed from this place. Maybe based on weight or something like that?
I’ve read a bit on NFC but looks like this is more to detect the moment where the smartphone is placed on the token, not to detect the moment it is removed…? Also, looks like this was a solution that is implemented in the smartphone (via some App) where I’d prefer to have something that does not depend on the smartphone running specific software, or maybe not even being a smartphone but any physical object where I might attach some token.
Did I miss something obvious, do you have any hints on how to get this done?
I am using a wireless charging station for steering my bedlights. When lying on the charger there is a sensor in the companion app (android) which tells what kind of charger is used.
When putting it on the charger before going to bed the lights in the bedroom dims down.
This only happens when putting on the wireless charger and not when charging with a cable.
A “force sensitive resistor” can probably do what you’re asking. It basically senses how much pressure is applied, which you can use to detect a weight being placed on it, or being taken off. They have ready made “pressure pads” which make it easier. I haven’t used one in HA though, but have used them for other ESP projects. So put your charger on the pad and you can detect when something (your phone) is put on it, or removed by the change in the reported resistance. Here’s one example of a ready made pad: Force Sensitive Resistor - Square - SEN-09376 - SparkFun Electronics
As this looks like quite some DIY project though, I just came up with the idea to “reverse” the NFC issue by using a tag on the phone and a separate reader (instead of reading within the phone)?