This is the best summary and explanation I have found regarding Helium, which is a decentralized network for connecting physical devices (IOT). Basically you would install 1 or multiple of these small hotspots in your home or office, and it earns you Helium tokens in exchange for you providing that hotspot to the network. It’s pretty neat! Not as profitable as mining Ethereum, but definitely a good way to earn some passive income without having any technical skills.