In 2014, Michael Brown, an 18-year old unarmed black man, was fatally shot by a white police officer in Ferguson, Mo. In the four months that followed, the stock price of the stun-gun maker Taser International, now known as Axon Enterprise, nearly doubled. The following year, the Department of Justice launched a pilot program awarding more than $23.2 million in grants to expand …

A team of researchers at the University of Washington has come up with a working prototype of a cellphone that doesn’t require a battery to make calls or send text messages – instead, it harvests energy from thin air, more specifically, radio signals. Right now, all it features is an LED light and buttons on a circuit board, however, a …