The Laptimer MK1 is a simple IR-based laptimer system. The receiver is connected to a modified stopwatch inside the car, and will "press" the appropriate button by means of an optocoupler. The transmitter is placed somewhere alongside the track, and sends modulated IR-light across the track. Each time the receiver passes the transmitter beam, it will activate the output to trigger the stopwatch. The receiver has a "dead-time" period to prevent re-trigging for a certain amount of time, adjustable by DIP-switches.
You can download the user manual (Norwegian) here: Laptimer MK1.
The schematic of the receiver ("save picture" or "save target" to get full size image) can be viewed below:
Last updated: 29-01-2004