Fiber optics are a great way to transfer huge quantity of data at lightning speed. Thanks to the property of total internal reflection, which allows light to flow through a glass fiber like fluid through a pipe, they can be used for communications at long distances and form the backbone of modern communication networks. However, water is also able to pull off the total internal reflection party trick, and [Mike Kohn] decided to see if it could be used as a communication medium, too.

The experimental setup consists of an ATTiny85 that receives signals over its serial port, and outputs the received bits by flashing an LED. This LED is attached to a plastic tube filled with water. On the receiving end, another ATTiny85 reads the voltage level of a photodiode placed in the other end of the tube. When the ADC detects voltage over a certain level, it toggles a pin connected to the serial RX pin.

Hooking the setup to a pair of terminals, [Mike] was able to successfully transmit 9600 baud serial data through a tube full of water with just an LED and a small microcontroller.

https://www.mikekohn.net/micro/water_optic_communication.php

A short video on illuminating and cleaving a fiber optic to use as a test source.

How to attach fiber optic filament to an LED
https://www.youtube.com/watch?v=zTD4xzlwiRU

Use a high-bright IC LED for best results

In this video, I show you how to make a fiber optic cable at home. This will allow you to bend light. You will need glass rod (I used borosilicate), heat shrink tubing, a heat gun, a torch, safety glasses, proper ventilation, and finally, a laser to test it all out. I was able to make 3 feet in a couple of hours. Enjoy!

This is an introduction to how to make your own optical fiber optic cable DIY for indoor lighting applications. I imagine it could be used for short data transfers optical cable but will not say for sure.

DIY Fiber Optics
https://www.youtube.com/watch?v=2l25LKTOTnc

Make your own fiber optics with some fishing line and a hair straightener.

How to Repair Fiber Optic Cable
https://www.youtube.com/watch?v=eISDl-zgWhE

The purpose of this video is to provide training on the repair limitations of fiber optic cable issues and damage. This online session will guide you through the main points of how to evaluate, identify, and repair fiber optic damage.

How to splice broken optical fiber cable practically
https://www.youtube.com/watch?v=JBVbyzCSUHk

Bill uses a bucket of propylene glycol to show how a fiber optic cable works and how engineers send signal across oceans.

Fiberoptics Fundamentals | MIT Understanding Lasers and Fiberoptics

Topics Covered: Why the interest in fiberoptics; How light propagates in an optical fiber; What determines the loss in a fiber; Single mode and multimode propagation; Single polarization fiber; Fiber amplifier operation; Fiberoptics applications in sensors and communications; Future developments.

Instructor: Shaoul Ezekiel
View the complete course at: http://ocw.mit.edu/res-6-005S08