A mechanical switch is arranged to electrically connect a power source to an electrical component. The switch includes a resilient structure, a first electrically conductive element connected to the power source and a second conductive element connected to the electrical component. At least one of the conductive elements is attached to the resilient structure. The switch is arranged such that the conductive elements are positioned out of contact with one another in the absence of a force being applied to the switch, and the resilient structure is moveable in response to a force applied thereto, the force being applied upon rotation of a tire to which the switch is connected. Upon the application of a force above a predetermined threshold, the resilient structure moves to bring the conductive elements into contact with one another, the contact electrically connecting the power source to the electrical component.