This project is for use with a centrifugal governor that I made using the Lego WeDo robot kit. You can see a video of it in action here: https://vimeo.com/131685447 Centrifugal governors consist of two arms with weights at the end, attached to a vertical column. When the column rotates quickly, centrifugal force will cause the arms to lift, triggering a mechanism that will reduce power to the motor turning the central column, hence preventing its speed from increasing any further. Centrifugal governors are commonly used on steam engines to control the speed at which they operate. For more information see: https://en.wikipedia.org/wiki/Centrifugal_governor In this machine, when the arms lift, the string attached to them lifts the roughly circular plate towards the bottom of the central column. This then allows the cams that are underneath it to lift up, so allowing the lever to which the tilt sensor is attached to move. Once the tilt sensor is activated, power to the motor is reduced, until the arms become a little lower, so allowing the plate to fall down, and returning the cams and tilt sensor to their original position. Power to the motor is then once again increased. This repeated action ensures that the speed of rotation is tightly regulated so that it remains within a narrow band of speeds. Every time the mechanism alternates between increasing or decreasing the speed, this project announces this with a popping sound. The mechanism is started with the green flag, and can be stopped gently by clicking the stop sign that appears on the screen. This will rapidly reduce the power applied to the motor. This stops the machine much more smoothly than if the machine is abruptly brought to a halt simply by clicking the usual Scratch stop sign. Pressing the space key will cause the motor to be accelerated to full power, so demonstrating how the machine would operate in the absence of regulation by the governor.
Centrifugal governors were used in windmills as early as the 17th century, but it is not known who invented them.
