Using IR emitter and IR rx to count laps

[sloper steve]

We slope race and guys have to move flags so we know when the planes pass a point.

Wouldn't the parts be cheap to power off your BEC using a resistor to power the IR LED aimed off one side of the wing.

On the hill you have an IR receiver that counts the laps.
It would have to add a lap then wait a few seconds before adding another lap if it still sees the IR so the plane can get away.

Making it work for more than one plane may be impossible?

Any ideas?

[Happy Hobit]

Hi Steve,

I/R does not work well in the light of day. Sunlight blinds it. The TSOPxx claims a range of 35 meters, but that’s in a dark room. Outside, in daylight, you’d be lucky to get 10 feet horizontal and if the receiver was looking up into the sky I doubt it would work at all. :(

If you can get around that (fly only at night) try using multiple I/R decoders in your receiver station that have built in demodulators for different frequencies. The Vishay TSOP48xx line comes in 7 different frequencies from 30KHz to 56KHz. (Your TV probably uses a 38KHz receiver.)

Then each plane modulates their LED at a specific frequency.

Jay