This is the new USB version, you can add the 5V power or without the power.

This Lap Timing System is a fully operational lap counting system for EC Models of all sizes.

The transponders are extremely small and can fit in all RC cars.

Every tiny and lightweight transponder is encoded with a unique ID. By crossing the start/finish line, the system is recognized and processed by the receiver module mounted to the top of the counting bridge.

Features:

• For indoor and outdoor tracks
• Unlimited cars running at the same time
• Personal transponder with unique ID (compatible with Robitronic)
• Small (only 12x12x6mm) and lightweight transponder (1.2g)
• Full USB support
• Receiver modules w/power LED and action LED display

System Requirements:

• Windows 2000, XP, Vista, Windows 7, Windows 8 or 8.1 (32/64-Bit system support)
• One available USB 2.0 port
• Installing drivers
• Build your own bridge by any material like 1" PVC pipe or wood. Height from the sensor to the cround should be  16"/40.6cm

Included:

• USB PC-Interface w/data cable (1)
• Receiver modules for track w/ max width (4ft/1.2m)