This wasn’t as simple as just building a device that pairs with your phone, since it needed to be accurate on the street level. March wound up designing his own iPhone app that could offer fine-grain turn directions that would help him get around at street level. It’s his first app, built in Swift, and March told Engadget that the experience was “a delight.”

Hardware-wise, the frames are CNC machined out of bamboo, with holes in the arms to house a pair of printed circuit boards and a coin battery. March also made his own lenses and polished them through, a