mbbolton96:
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Now, what I want to do is to transmit a wireless signal from one car to another, namely that a blinker has been activated, so that it would be able to warn a car 2 or even 3 cars back.
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Light is a wireless signal; IR light is also not visible and easily directional.
How I would approach...
IR LED of high-intensity variety mounted in rear window with flashlight-ish reflector. Sends out signals pulse with: sync header + L/R data + repeat count + checksum. Initial repeat count = 0.
1st car behind turning car picks up signal front IR receiver and repeats it out back window BUT adding +1 to repeat count.
2nd car repeats #1 car ...
After "n" cars, the repeat does not happen... Based on some magic number... City vs rural, speed, etc.
Cars that receive the signal perform whatever notification is intended... Sounder, beep, LED, etc.