A mechanical keyboard for use on a touch screen comprises an individually and resiliently depressible key and a network of electrical conductors. They key includes a user-facing outer portion and a screen-facing, electrically conductive inner portion, the inner portion being configured to approach the touch screen during depression of the key. The network of electrical conductors is configured to conduct a drive signal to the inner portion of the key, the drive signal being received, during the depression of the key, at a locus of touch screen directly beneath the key.