https://github.com/carrascoacd/ArduinoSIM800L

Mean opinion score (MOS) is a measure used in the domain of Quality of Experience and telecommunications engineering, representing overall quality of a stimulus or system. It is the arithmetic mean over all individual “values on a predefined scale that a subject assigns to his opinion of the performance of a system quality”.[1] Such ratings are usually gathered in a subjective quality evaluation test, but they can also be algorithmically estimated.
MOS is a commonly used measure for video, audio, and audiovisual quality evaluation, but not restricted to those modalities. ITU-T has defined several ways of referring to a MOS in Recommendation P.800.1, depending on whether the score was obtained from audiovisual, conversational, listening, talking, or video quality tests.

Source: Mean opinion score – Wikipedia

Source: Xiaomi Mi Smart Home Kit: full specifications, photo | Xiaomi-Mi.com

Source: Welcome to Smart Home with QIVICON – QIVICON

Douglas Carl Engelbart (January 30, 1925 – July 2, 2013) was an American engineer andinventor, and an early computer and Internet pioneer. He is best known for his work on founding the field of human–computer interaction, particularly while at his Augmentation Research CenterLab in SRI International, which resulted in creation of the computer mouse, and the development of hypertext, networked computers, and precursors to graphical user interfaces. These were demonstrated at The Mother of All Demos in 1968. Engelbart’s Law, the observation that the intrinsic rate of human performance is exponential, is named after him.
https://en.m.wikipedia.org/wiki/Douglas_Engelbart

https://en.m.wikipedia.org/wiki/Stewart_Brand

L band is the Institute of Electrical and Electronics Engineers (IEEE) designation for the range of frequencies in the radio spectrum from 1 to 2 gigahertz (GHz).

Source: L band – Wikipedia

This tutorial is going to teach you basics on using Optical Dust Sensor.

Source: How to Interface With Optical Dust Sensor: 9 Steps (with Pictures)

Source: RFM12B-S2 Wireless Transceiver – 434MHz – WRL-09582 – SparkFun Electronics

Source: Cheap 433MHz Transmitters | Majenko’s Hardware Hacking Blog