The Light Gates for the TSA come in two parts: the Source, and the Receiver.

The Receiver connects directly to a DIN socket on TSA. It uses a photodiode which has a daylight filter. This means that pupils working in a lab near a window should experience no problems with ambient light.  The green light on the Receiver indicates that the light gates are aligned and ready to be used.

The Source was originally a lens end bulb but this has been replaced with an infrared source with the result that battery life is now much longer.

With the infrared source, separation distances of up to 50cm between the Source and Receiver are possible. Much greater distances can be achieved if the Source is replaced with a 'Mag Light' type torch which can be focused. Do not use an LED torch or laser as these do not emit infrared.

The TSA Timing device is not included, but is available to purchase separately.