So I have this TV remote. I've been playing around with remote controlling things around the house, and finding different remotes I can read the codes from. The smart TV has this two sided remote, and when I first looked it over, I didn't see the telltale 'IR window' at the front that lets out IR light. Hmm, RF remote, I thought.
Opened her up and no, it's still an IR remote, but the whole case is made of some 'opaque' plastic that lets IR through. Neat. Wizardry.
But furthermore, it has 2 IR leds that both shoot off signals. Well, it has 4 IR leds, 2 sets of 2, one each per remote orientation.
I've never seen such a thing. Through the phone camera it appears the leds don't flash the same pattern, but could just be a camera artifact. What's the deal? Is this remote using two leds, differently modulated, to send 2 sets of serial data at a time? Different wavelengths of IR maybe? Or is this just a distance gainer with 2 identical leds?
Would an Arduino be able to fire off two IR leds with different protocols simultaneously?
Put together an IR sensor, every button sends a consistent code to Serial Monitor, but I'm wondering if I'm only picking up half the signal since my receiver is just 1 wavelength.
Two LEDs emit more light than one.
Could also be a "normal" wide-angle LED, and a narrow beam LED for distance.
Old 9-volt remotes had four LEDs. They worked to at least 12 meters without carefull aiming.
My old 4-LED remote dropped off at ~60 meters. Have some fun with the neighbours.
You're lucky if modern 1-LED "smart" TV remotes do 6 meters with a stretched out arm.
Serial data stream, so only one command at the time.
But IR commands are very short.
If it's a "learning" remote then the second thing that looks like an LED is probably the IR receiver.
I find myself being more fascinated with the plastic that the IR passes through. Maybe it's just a function of thickness? I mean many, many, remotes have had money spent on sticking those windows on, and it seems that wouldn't have survived if it wasn't necessary.
I’ve noticed when using the RPi IR camera module that black acrylic is often completely transparent to
near IR, so its a godsend for people making spy cameras, forget that one-way mirror stuff from the 60’s,
never trust black plastic to be opaque.
You never know just what is transparent to IR without more checking - remember the flap a few years back when people discovered that the Sony video cameras in "night vision" mode (which sees IR) could see through some clothing and bathing suits? Made the national news for a while as people discovered just was was "transparent" and what wasn't.