A system and method for controlling toy vehicles has a plurality of pads
coupled to a central station. Switches in the pads may be closed to
select toy vehicles and the operation of motors for moving the vehicles
forwardly, rearwardly, to the left and to the right and moving upwardly
and downwardly a receptacle or bin for holding transportable elements
(e.g. marbles). The pads may be set in a mode to allow sharing of a
vehicle by more than one pad. The pads are connected by wires to the
central station, and may be interrogated selectively, sequentially or
simultaneously by the central station. The central station forms packets
of signals representative of the switch closures of the interrogated
pads, and transmits the packets over a modulated carrier frequency to
receivers in the vehicles. Each of the packets includes a binary signal
addressing the vehicle selected by the pad whose switch closures are
represented by the packet of data. The central station prioritizes the
transmission of the packets to improve vehicle control. An accessory, or
a second central station, may be coupled to a smart port of the first
central station. When the pads are interrogated by the central station,
the signals from the pads may be routed to the accessory or second
central station for processing, then sent back to the first central
station for transmission to the vehicles. The pads include a flashback
feature that automatically selects a previously selected vehicle. The
motors of the vehicles may be energized using pulse width modulation to
control the speed of the motor. Signals received by the vehicle are
asserted to the motors in the first part of a duty cycle. The vehicles
monitor all packets, and decode packets addressed to the vehicle to
execute the commands represented by signals contained within the packet.
When a packet is determined to be invalid, the vehicle ignores the
packet.