As in this answer I plan to use a 5V neopixel RGB LED as both transmitter and receiver to transmit information between ATMega328 boards via fibre optic cable. (This is the Forrest Mimms strategy, for the curious)
Ignoring the coordination problems inherent in it being a half-duplex system (both sides can talk, but not at the same time), what kind of circuitry would I need to switch the LED's mode?
Based on the title of this paper I assume it's possible: Half‐duplex visible light communication using an LED as both a transmitter and a receiver but the paper is paywalled so I can't look up how they did it.
(I assume someone on here has access to that journal, though?)
Bandwidth can be ridiculously low; I'll only be sending ~32 bits max per message, with messages on the 10 to 30s range.