arduino. This is a very solid way when against a Terran opponent. First escape a Gateway, Cybernetics Core, Gateway, then the Robotics Facility. Get an early Zealot along with a Sentry to Force Field your ramp in case you are under early pressure. As soon as your Robotics Facility gets done, make an Observer. This will offer you a large amount of intelligence with what your attacker does so you're able to react accordingly.