A wireless controller, such as a keyboard, and reader combination
comprises a controller having a plurality of keys, one or mechanical to
electrical energy converters providing energy from key activation, an
antenna, and one or more passive transponder circuits, coupled to the
antenna and associated with the keys. The passive transponder circuits
provide a coded response identifying a key in response to key activation
employing power from the key activation to modulate the interrogating
field. In particular backscatter modulation using the reflected
interrogating field may be employed. An associated reader includes a
source of the interrogating field applied to the antenna of the keyboard
and a decoder for determining the coded response from the passive
transponder circuits.