1. Vex 1.0 © 2005 Carnegie Mellon Robotics Academy Inc. Electromagnetic Solenoid This lesson will explain the purpose behind an Electromagnetic Solenoid and also give you steps on how to create one. The solenoid is used with the Vex Pneumatics Kit. Use the slide show for building instructions. Use the animation to see how a solenoid works.

2. Vex 1.0 © 2005 Carnegie Mellon Robotics Academy Inc. Solenoid Background A solenoid is a wire wound coil that creates a magnetic field when energized. A solenoid valve is a valve operated by a solenoid coil. Solenoids are devices that turn electrical energy into linear motion. The solenoids in the Vex kit are electric solenoids used to control pneumatic cylinders.

3. Vex 1.0 © 2005 Carnegie Mellon Robotics Academy Inc. Electric Solenoids Electric Solenoid Valve –Uses electricity to control the solenoid action –Electric solenoids are the type the vex controller uses. –Vex solenoids attach via input port to get 5v supply voltage.

4. Vex 1.0 © 2005 Carnegie Mellon Robotics Academy Inc. Solenoid Physics An electric solenoids consist of an inductive coil wound around a movable steel or iron slug.

5. Vex 1.0 © 2005 Carnegie Mellon Robotics Academy Inc. Solenoid Physics The coil is shaped such that the slug can be moved in and out of the center, altering the coil's inductance and thereby becoming an electromagnet.

6. Vex 1.0 © 2005 Carnegie Mellon Robotics Academy Inc. Solenoid Physics The force applied to the slug is proportional to the change in inductance of the coil with respect to the change in position of the slug, and the current flowing through the coil.

7. Vex 1.0 © 2005 Carnegie Mellon Robotics Academy Inc. Solenoid Physics The force applied to the slug will always move the slug in a direction that increases the coil's inductance.