Ballactivated

Ballactivated describes devices, sensors, or mechanisms that are triggered by the presence or motion of a ball, typically a small metal or ceramic sphere that rolls within a cavity or tube. Commonly implemented as ball switches or tilt and vibration sensors, such devices rely on the physical movement of the ball to bridge or break electrical contacts, producing a switch-like action without requiring active electronics.

Operation is simple: a ball sits inside a housing with conductive contacts. When the device’s orientation or a shock causes the ball to roll into a position that bridges contacts, the circuit closes (make state). In tilt-based variants, the ball moves in response to gravity to indicate a particular angle. In vibration-based designs, the ball’s movement during movement or impact triggers a change in state. Ball switches are often used as rugged, low-power sensing elements.

Construction and variants vary, but most ballactivated switches use a tube or chamber with two or more conductive contacts and a movable ball. The ball may be metal or a conductive coating on glass or ceramic. Some designs rely on the ball to complete a circuit between fixed contacts, while others use the ball to actuate a secondary mechanism or reed switch. Materials are chosen for wear resistance and corrosion resistance in the intended environment.

Applications include simple tilt detection, vibration sensing, low-cost position or event sensing in toys, arcade machines, alarms, and basic robotics. They are valued for simplicity, robustness, and low cost, but can suffer from contact wear, dirt ingress, bounce, and limited current handling. Mercury switches are environmentally restricted, making ballactivated switches a common non-toxic alternative.

See also: tilt switch, vibration sensor, reed switch, mercury switch.