Operating rooms would be a tangle of wires if all the equipment in them were hard wired to controls within the surgeon's reach. It would also be impractical. Wireless foot controls, however, eliminate the nuisance of wires under foot and remove the most common source of failures for foot controls: wires and connectors. The wireless footswitch developed by my company uses an infrared transmission to flood the operating room with a 360° spread using several IR emitters. This means receivers can be anywhere within range and need not be line-of-sight.

The footswitch clears up several problems in the OR: tangled wires, equipment locations limited by wire lengths, and cleaning wires between surgery. Transmitter range is typically 40 ft between transmitter and receiver. The transmitter has up to five switch functions. Each pedal may have single or dual-switch functions. Receivers have to be interconnected to the equipment in place of wired footswitches surgeons would normally use. Modifications requested by some users include additional pushbuttons and double-pole relays.

Multiple footswitches will work in the same room without crosstalk, thanks to encrypted carrier codes and dedicated OEM codes. The system uses standard AA batteries, requires no calibration, and meets applicable UL, CE, and EMC requirements.

The footswitch is IP68 rated and can be fully immersed in fluids, including cleaning solutions. Also, if a signal interruption occurs, the system is designed to react safely in the off mode. The switch's ergonomic design includes large pedal openings to accommodate surgical foot apparel. LEDs on the receiver indicates the function in use, a low battery, and power connection.

The footswitch by the numbers

The footswitch meets European Norm 60529, Degree of Protection, and is rated IP68. The transmitter batteries last about 200 hrs at 50% duty cycle. Power consumption in standby is about 100µA. The receiver power requirement is 6 Vdc at 200mA. The receiver uses SPST or SPDT relays with 0.5-A contacts. The unit is classified to UL60601.1, CE and EMC requirements. The transmitter weighs 5.5 lbs with batteries and the receiver, 0.45 lbs.

Switches and receivers can be teamed several ways. For instance, four separate transmitters to four separate receivers, two separate transmitters paired to one receiver, or two separate transmitters paired to two separate receivers.