Apologies in advance for the lack of step-by-step instruction. I'm not in the habit of taking photos while I'm working, so this machine got built and now I'm making the instructable after the fact. Hopefully it can give people some ideas and inspiration though!

You will need a front load washing machine that is mechanically sound but electrically broken. You will also need a stationary exercise bike, a bike chain, a rear bicycle wheel hub that can take a 6-bolt rotor, a ribbed belt and ribbed pulley from a car, and some hoses for the inlet and outlet of the machine.

Step 1: Fit Pulley Onto Hub and Fit Chain

The drive system works by the rider turning the bicycle cranks/pedals which drives the chain, which in turn drives the hub, which in turn drives the pulley belt, which then drives the washing machine drum.

A pulley needs to be attached to the bicycle hub. I did this by drilling 6 holes in the pulley that line up with the 6 bolt holes in the hub and bolted it on. In order to accurately drill these holes, use a rotor with the same hole pattern to mark out the positions and then mark them with a punch.

I fitted gears onto this machine but in hindsight I wish I just had a fixed gear setup. One gear with the ability to rotate forwards and backwards, which would provide a better wash. One gear can be used for both the slower wash cycle and the much faster spin cycle - you just need strong legs to push it. As expected it's much harder to push when full of water than after the water is drained.

Step 2: Fit Belt Onto Drum and Tension It

It is critically important to note that washing machines have a suspension system on the drum, so that if you simply try to tension the drive belt it will only pull the drum off at an angle and leave the drive belt loose. A counter force is required to keep the drum centred. So you'll end up with the drive belt pulling the drum one way while the octopus straps (rubber straps) and springs (seen in the photo) pull the drum the opposite way to balance it.

Step 3: Connect Hoses

After you've found the appropriate inlets and outlets for your machine, connect a garden hose to supply water, a wider flexible pipe to the outlet to drain away the dirty water, and a funnel to the detergent inlet.

Step 4: Raise the Outlet Pipe to Contain Water

You could go to the trouble of putting a valve on the outlet pipe so that it contains the washing water until it's ready to be drained away. Alternatively, you could simply raise the end of the outlet pipe above the height of the drum and then bring it down when you want to drain the dirty water.

And thus concludes my most vague instructable yet - good luck!