(re)Using old cellphones
(re)Using old cellphones
The HomeAssistant app can pull data from a lot of smartphone sensors but it depends on what the sensors are vs how useful they will be. I tend to use the battery level sensor on my wall mounted devices that are used as HomeAssistant controllers. This way I can turn a smart switch on and off that controls the power brick that charges the tablet. It turns on at 30 percent and off at 80.
I also setup custom dashboards for devices based on location, near a door has camera feeds for multiple cameras and controls for lights and switches nearby. Master bedroom has automations that can kill every light in the house with feeds for a front door and back door.

Blueprint to control the charger for a permanently installed tablet control panel with a controllable switch device on the charger. You can select the battery sensor, the charged percentage, the low charge percentage and the switch to control the charger. Screen Blueprint Click the badge to import this Blueprint: (needs Home Assistant Core 2021.3 or higher) Or import this Blueprint by using th forum topic URL: blueprint: name: Wallpanel Battery Management description: 'Control the c...
I went this route a while ago using old cellphones and ultimately found them not worth the “savings” over even thirty dollar IP cams. There are just too many fiddly things that interfere with their reliable operation: