Many laptimers for FPV racing are using IR transmitters on each copter for tracking. Just out of curiosity I build myself one with 5.8 GHz receivermodule(s) (RX5808) and used the RSSI for the detection. The module has no antenna connected such that the receiption is only good within a few meters.
An Atmega32 is reading the RSSI and triggers if it goes above a certain threshold. Also I connected a serial mp3 player for sound and voice output.
Miniquad: http://fisch.suroot.com/index.php?nav=miniquad
Motors: Sunnysky x2204s
ESC: Kiss ESC 12A
Props: DAL 5040
FC: Naze32 with Cleanflight, MW 2.3 pid controller, oneshot enabled
Receiver: Frsky D4R-II
Lipo: 3S 1600mAh
Onboard Camera: Mobius with 2.1mm Lens
Music: Eric Florez - Ascension
https://www.youtube.com/watch?v=n-Hn7JqIBoQ
