Thing Dispenser
This is not an easy project, but i believe it is doable (?). This project will create a physical device that will dispense a "thing" (dog treat or dry erase marker) when a txt message is sent to a phone number. The physical device will have a Raspberry Pi micro-computer connected to an Arduino board, which in turn is connected to a servo motor to actuate the dispensing.
This project was described in the March 2018 MAKE magazine (MAKEzine), [here
To get started, I found the following video to be useful; if this physical device is going to respond to a txt message, then there must be some link between the act of sending the txt and the dispensing of the thing. In the following video, a basic description of something called an API (Application Programming Interface) is presented here