Rope as Communication Media I'm a computer student that used to play microcontroller and sensor. I'm not sure whether this topic fits on this site.
I'm thinking about using rope as media communication instead of fiber optic. I know this is a primitive method to use rope. The reason I use it is because of cost.
Basically, information that devices used to transmit or receive are just binary data, which is just 1 or 0.
1 or 0 is just a label that represent two possibilities. Fiber optic has label 1 if there's light or 0 if no light.
Now we can replace fiber optic with just a rope. But how we label 1 and 0 with rope while rope can't transmit light? I think we can encode it in other way: 1 for shaking rope (create wave) and 0 for idle rope. Or, alternatively: 1 for pulled rope and 0 for idle rope.
And then sensor detects its label.
I don't know how best to label it; I still haven't experimented; so I think theory first is better.
The problem is, what are the important parameters?
Type of rope, dense of rope, method of labeling, and etc.
 A: If you want to use this as a link between standard computers or microprocessors you will have to design and build a encoder to turn voltage levels into signals on the rope at the transmitting end and a decoder to turn rope signals into voltage levels at the receiving end. For two-way communication you will need two encoders and two decoders. The encoders and decoders will have to be partly mechanical. Although rope itself may be cheap, designing and building the encoders and decoders will not be so cheap.
And, as other replies have pointed out, the bandwidth (information carrying capacity) of a rope communications channel will be very low and its reliability (the chance of correctly receiving the signal that was transmitted) is likely to be low as well. You can compensate for low reliability by introducing redundancy or error-correcting codes - but that further reduces the bandwidth.
A: A tight rope or an elongated solid object (e.g., a piece of pipe) will support elastic waves. The information can then be encoded by modulating wave amplitude, just as it is done with modulating the amplitude of light in fiber optics. The difference is that here we deal with much longer wavelengths, so we need longer wave packets and the information capacity of the channel will be very low. It is also likely to suffer from high dissipation, so that one won't be able to transmit information very far.
If the cost is the main issue, one could consider creating an open air optical transmission line using a laser pointer.
