The machine is built using the read/write-arm from an old harddisk drive and some metal parts of an old cdrom drive for the chassis. The circuit that controls the levers coil is really straightforward and uses only a few discrete components and a relay. The light bulb serves two purposes, as a simple resistor it limits the current going through the lever arms coil and at the same time it optically indicates when the tea is ready! The timing is not really exact, due to the simplicity of the circuit, but it is just right considering that for brewing a tea there is no necessity of second accurancy.