What do  you do with an old, broken treadmill that's taking up space?  Hack it up and convert it to a Bicycle Dynamometer!  What, you may ask, is a dynamometer?  Well, simply put its a machine used to measure power output- usually of an engine, but in this case, its measuring the power output of YOU!  How much horsepower do you put out?!

This project has given my students a lot of enjoyment- they love competing against each other to see who is the "fastest" or "strongest"... and then they discover that they are only putting out maybe 1/3 of a horsepower!

Step 1: Gather Supplies

Get all your stuff together.  The big thing, obviously, is the treadmill.  You don't need it to be complete, but you should at least have: 

Electric motor & drive parts
Covers come in handy later, but not necessary.

***NOTE***  You must make sure the motor in the treadmill will work as a generator!!!  Hook up a volt meter to the wires coming from the motor and spin it BACKWARDS.  If you can measure a voltage, it will work as a generator.

I was lucky enough that our school was throwing out a pretty nice one that wasn't working- something wrong in the control panel.  Everything else was fine!

You will also need a large assortment of tools for this project which will depend on your treadmill.  At the minimum you will need:

Layout tools- square, tape measure, ruler, scratch awl, markers, pencils, etc.
Welder and welding gear (hood, gloves, etc)
Cutter of some sort- plasma, torch, or even a hacksaw.
Wiring tools
Electric Tape
Duct tape.  You never know, right?!

Other Supplies you will need:

2 digital multimeters (cheap ones run about $3.00)
Some Tie-downs
A Bicycle
A light or something else that requires about 120v to act as a load
Wire connectors and maybe some wire

<p>In your last picture you are not using the tension cords to tie the bike down. Is this true? does it work without them without slipping?</p>
<p>i would also like to know if this would work for a scooter</p>
<p>Theoretically you can use this method to calculate the horsepower of anything that spins. That said, if it was me doing the testing I probably wouldn't put anything on it that would have more power than the electric motor in the treadmill originally put out. </p>
could you use this to measure the power of a scooter or a small motorcycle?
As I recall, there are some AC motors that don't work (easily)... I only used the treadmill motor because I had it, it was free, and it worked. Very simple to test- hook up a voltmeter to the motor and spin it- if it generates electricity, it will work.
Fantastic Idea! I was going to use the same dynamometer principle to measure the output of a small 2 stroke piston engine I have. But, I need to know, does any kind of AC Motor do or did you use the treadmill motor for a specific purpose? For example, can I use a squirrel-cage motor? maybe I need some excitation current beforehand?
I can see that the final project is quite simple, guess any working generator will do the trick, am I right? can I use a car alternator or anything like that?
Yes, you should be able to use any type of generator. I have seen a few bicycle powered alternators, but I'm not sure how the wiring would work. The nice thing about using a treadmill is that you already have the rollers. You could put an alternator on the bike in place of the back tire, but I don't know how &quot;accurate&quot; that would be for calculating to-the-ground horsepower...
This is a great project, especially to give students some fun hands on science! I wonder if the original display on the treadmill would work if you hooked it back up (and maybe reverse the connections)? Then you'd be able to see your speed. Since you're handy with a welder, it be a great addition to construct a bicycle trainer style mount to secure the rear axle in place. Well done!
Thats sick! Is that a 90 in the background

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