a publish-subscribe based "light weight" messaging protocol for use on top of the TCP/IP protocol. It is designed for connections with remote locations where a "small code footprint" is required and/or network bandwidth is limited.” Wikipedia
a credit-card-sized single-board computer developed in the UK by the Raspberry Pi Foundation with the intention of promoting the teaching of basic computer science in schools.”
GPIO A traffic light representing the state of the tests on the build server. Light a red light when one or more test fails. Otherwise show green light.