- Internet router rebooter. Sometimes routers stop working for an unknown reason. Even those network devices that are considered reliable may fail a couple of times a year. Mankind has developed the ultimate solution for it: power off/on cycle. Therefore, the requirement for the device is to resemble what human does: to check availability of www.google.com through router's wifi, and restart the router (by turning it off and on) when the Internet disappears.
- UVC lamp timer. Ultraviolet-C can kill Covid-19 (among other life forms), but it is not safe to turn on the lamp (you have to wear a special goggles which is sometimes inconvenient). So, the requirement is to turn on the lamp either remotely, or with a button (after some delay), and turn it off automatically after 20 minutes of exposure. The device must also work reliably without internet/intranet (operatable by a button).
- Scheduler. Turn on/off holiday lights on schedule (when it is dark, but no one is sleeping yet), or turn on the storage water heater at night (when electricity is cheaper because everyone is asleep and not using it).
These apps have been in use for about a year, so they can be considered relatively reliable. Here are some details.