Back during my phd I worked in a project that set up sms transponders onto the handles of water handpumps in kenya.

So whenever a pump was misbehaving or broke, we would observe it all on a webpage and a technician would be alerted to fix it.

Later on some ML was strapped to the SMS data to predict failing pumps before they failed.

Good stuff. sms can be very powerful in the right setting.

Don't know what the author means by free here though. Sms is something you pay for, one way or another.