Kevin Karhan :verified: (@[email protected])

@[email protected] @[email protected] @[email protected] @[email protected] @[email protected] granted, this isn't rocket science as both high-quality, rugged (industrial grade temperature range), longlife LEDs do exist and both colour-filters for input and output that are colour-stable yet affordable with low light loss are existing on the market. If we were to look at COTS parts, we shurely should look at LEDs and Lasers in common wavelenghts. These are the ones where one can find on the market: ``` 940 nm (medium-IR, modern NV) 850 nm (near-IR, old NV) 780 nm (near-IR; CDs) 670 nm (red, HiVision Laserdisc) 650 nm (red, DVDs) 638 nm (orange) 532 nm (green) 510 nm (bright-green) 488 nm (blue) 405 nm (blue-violet, HD-DVD & BDs) 385 nm (violet, *"black light"*) 365 nm (UV, document verificators) ``` Assuming those get only `monomode` each and we're going with 10/12 error correction that means we got 10x the available spectrum and 10x the bandwidth of the RONJA at the same baud rate. OFC I'd assume for cost reasons it would rather be a a *"RGB+"* setup with a potential "`multimode`" setup to reduce costs for parts whist achieving the same throughput at lower baud rate. ``` 940 nm (IR) 650 nm (red) 532 nm (green) 405 nm (blue-violet) 365 nm (UV) ``` In the end, component costs and -limitations are what limit the "visible light PtP links" performance... - OFC getting one of those cheap 500mm/800mm f/8 optics and 2x teleconverters to zoom onto the other end as well as recessing it into a case (similar to a CCTV camera or rather telescope) could also yield better results and reduce issues with light bleed and disruptions even when installed at suboptimal angles with "noise sources" (ambient light pollution, sun) disturbing. In the end this could even adapt the link width automatically and even renegotiate it with any switch if done properly, as downgrading to 10 Mbit/s is preferable to total link loss... In fact, companies like [TESAT](https://www.tesat.de/products) already do this for their optical intersatellite link systems, delivering up to 100Gbit/s over 80.000km at 340W power draw and 34kg weight. So I'm shure 1/100th in terms of speed, power consumption and 1/10.000th of lenght and 1/4 of weight is achieveable with COTS parts.

Kevin Karhan :verified: (@[email protected])

:boost_ok: Does anyone have the full #specifications for [IrDA](https://en.wikipedia.org/wiki/IrDA) #archived somewhere? Because I'm looking for a good, short-range protocol that is less complex than #LiFi [*](https://en.wikipedia.org/wiki/Li-Fi) for a [*"digital dead drop"*](https://en.wikipedia.org/wiki/Dead_drop#Modern_techniques). Most notably because [USB dead drops](https://en.wikipedia.org/wiki/USB_dead_drop#Potential_drawbacks) have a shitton of disadvantages as #USB is not designed for that in mind, is extrenmely susceptible to sabotage and vandalism as a #PirateBox [*](https://en.wikipedia.org/wiki/PirateBox#Uses), less complex than #FreedomBox [*](https://en.wikipedia.org/wiki/FreedomBox#Commercial_product) for #Sneakernet [*](https://en.wikipedia.org/wiki/Sneakernet) operations. Given the IrDA spec is relatively simple on the physical interface, reimplementing it with visible light would allow for more options espechally when it comes to *"broadcasting"* data to multiple devices when #datacasting like #Toosheh [*](https://en.wikipedia.org/wiki/Toosheh) would be overkill...

RONJA - Wikipedia