Abstract: A wireless communications unit is provided, such as a portable unit to serve as an access point and/or a repeater node in a wireless meshing network, including at least two removable power source modules engageable with and electrically connectable to the unit to provide electrical power thereto, and a mechanism to allow selective disconnection and removal of one power source module from the unit while maintaining connection and retention to the unit of another power source module. The mechanism comprises a rotatable wheel having a radially projecting portion (such as a cam lobe). When the wheel is rotated the projecting portion bears against a part of the first power source module to push it into an ejected position while electrically disconnecting it from the unit, to allow removal and recharge/replacement.

Abstract: A wireless communications unit is provided, such as a portable unit to serve as an access point and/or a repeater node in a wireless meshing network, including at least two removable power source modules engageable with and electrically connectable to the unit to provide electrical power thereto, and a mechanism to allow selective disconnection and removal of one power source module from the unit while maintaining connection and retention to the unit of another power source module. The mechanism comprises a rotatable wheel having a radially projecting portion (such as a cam lobe). When the wheel is rotated the projecting portion bears against a part of the first power source module to push it into an ejected position while electrically disconnecting it from the unit, to allow removal and recharge/replacement.

Abstract: The invention generally relates to a field regulator, particularly a field regulator for a resonant circuit, a transmitter including such a field regulator, a proximity detection system including such a transmitter, and a method of regulating a resonant circuit. In one aspect the invention provides a field regulator for a resonant circuit, the resonant circuit including an inductor coil around a core, the field regulator including a DC bias circuit configured to apply a DC bias current to the inductor coil for regulating an electromagnetic field generated by the inductor. The DC bias circuit can be used to selectively change the inductance of the inductor in the resonant circuit so as to maintain a consistent field strength in a changing environment, particularly to take into account the presence of large metal bodies which might otherwise adversely impact on operation.