The image to the left is a robotic tank powered by the popular Lego Mindstorms NXT kit. The brains rest inside of a tube, including the controller brick, ultrasonic range finder, a gyroscope, and a compass. Two sets of treads surround each edge of the tube making us wonder which end is up? We’ve embedded a video of this beast after the break. You’ll see that the tank is incredibly agile in this configuration.
To the right is an aquarium heater. [Dave's] kid were growing some tiny water dwellers which we’ve always know as Sea-Monkeys. The problem is that the tank needs to be between 72-80 degrees Fahrenheit for the little shrimp to thrive. He dug out his NXT controller and paired it up with the Lego temperature sensor and a dSwitch relay. This setup monitors the Aquarium for temperatures between 72-78 degrees and switches a lamp on an off to regulate the temperature. This keeps his kids and the stagnant pool happy.