If Li-Fi possible with a Propeller?

Kirk Fraser

I watched a YouTube video on Li-Fi which can deliver high speed wifi by an ordinary LED lightbulb. I thought maybe a pair of those with a pair of binoculars aiming a webcam at a distant light bulb might allow wifi to go beyond the usual 100 feet cheaper than usual. It would be great on the farm and for some neighborhoods where internet is not limited to one house per account.

Mike Green

It's probably possible. Many years ago, Datapoint had an optical network link that operated reliably over a couple of miles except during heavy Texas rains. It used a pair of Fresnel lenses about 12-15" diameter along with an LED at one end and a phototransistor at the other along with appropriate drivers and amplifiers. The details of how the light is generated and detected determine the range, speed, and reliability (Your mileage may vary). For speed, I'd avoid the lightbulb and webcam and stick with the LED and phototransistor.

Mike Green

Remember that the lightbulb and webcam are doing all sorts of stuff internally that really slow down any possible data transfers. Webcam sensors are not designed for speed.

yeti

I'm curious to see some homegrown LiFi alikes.

...but some cheap OpenWrt routers with external antennae, perhaps configured as mesh, may be even cheaper and easier to manage.

Ronja may be interesting too.

Brian Fairchild

Kirk Fraser wrote: »

...aiming a webcam at a distant light bulb might allow wifi to go beyond the usual 100 feet cheaper than usual.

My webcam has a maximum frame rate of 120 frames per second and that's fairly typical. So your absolute maximum bit rate would be 120 bits per second!

And there are plenty of good technical reasons why you'll struggle to reach even 1/4 of that rate.