Let's Make Robots!

Propellor Based - Bike Rollers - Draft Idea Stage

I am an avid Bike rider and now winter is approaching the idea of jumping on my "Rollers" during the dark evenings to keep up the fitness campaign frankly gives me no incentive .....at all ..... nada ..... however it has to be done (i am not the only one for sure).

My Guess is there could be quite a market in the racing Cyclist community for the proposed ideas below..

Riding 30-60 minutes on "Rollers" is pretty boring......... I want to change this ....

My Wish is to install my "EasyProp" Propellor chip into the set up, i already have a composite video screen and heart monitor.

As well as the normal (boring) speed/distance/calorie-burn/cadence parameters........

i recon i could also more importantly include on the screen. (in priority order).

  • Interactive games.... what would be fitting games during training ?
  • MP3 or wav playing.... with fitting high rev music.......but what ?.
  • recording and storing training profiles.

With all that power going to waste it would be a neat way to generate some free electrical power - but i have no idea how and what to fit to the rollers.

I made a system with the Arduino last year ......but the propellor chip has so much more to offer......

So Any radical....abstract ..... inspiring ideas would be greatly welcome.

The Video (Slo_mo_ish) shows my set up - the rollers are plastic (generates a mega amount lot of static) , with ball bearing races, speeds of 60+ Km/hr is possible on these types or "Rollers".

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Get an old car alternator, use a belt and pulley to connect it to the bike rollers. This will generate about 14V DC. Connect a heavy load (e.g. car head lights, batteries that need charging etc.) to it with a FET in series. Use PWM to control the FET. This will let your controller vary the load electronically.

This reminds me of an episode of "Gilligan's Island". All you need is some bamboo and coconuts!

Thanks for the idea - i have seen these types used on cycle Turbo trainers, they are however quite noisy, and produce quite a bit of drag, the efficient ones i have seen use "Fly-Wheels" to keep it in a constant flow........

My guestimate of "current" requirements (prop.board&screen) would be say 250mA continous. So maybe i could get away with a lighter system.

I had thought about the oldie dynamo generators on the wheel , however they are a little agressive on my thin racing tires !!!!

One idea i have is to sew/glue magnets into a strip of velco which would then wrap around one of the rollers, i would then need to work out a coil system ...... making it a "brushless motor" in reverse........as it  where .....(heck then if i slapped a 12volt battery onto it i would not need to cycle at all)

If you only want to generate that small amount of power the the magnets on the roller might work (use neodymnium).

For the coil it might work with an old speaker where the cone has been destroyed. This way you have a coil mounted in an iron housing. Just have the magnets whiz by the center of the coil. Another idea would to be to use a coil from a relay. In both cases bigger is probably better. A solenoid might also work.

More windings = more volts.

As for magnets: stronger = more volts. The real "kick" comes from the change in the magnetic field: full on to full off in the shortest possible time. Even better: from full South to full North (magnet wise) in a split second.

Rectify AC to DC with diode bridge as required.

So - perhaps it's possible to monitor steering and speed, and rerout it into a game controller for something like mariokarts?  I guess it would take a bit of power, but you could hook it up to a PSP2 or something with lower power demands than a tv?

Just as a slightly off-topic question. Is it possible to steer your bike OFF the rollers completely - what happens when you do - or does everything just grind to a halt..?


Its impossible to steer the handlebars whilst on the rollers, if you do then its instant dismout at the attained speed - not a pretty site, but with quick release cycle shoe bindings all that is lost is ones "Pride".

The idea with the "rollers" is to keep central to the roller , you can do this by leaning left or right (slightly) and you can drift safely +/- 10 cms ........ so it could be possible to detect left and right influences.

To self power the units i would guess on 300ma max so i rekon its in the range of a simple (hmm) generator.

I will start with this:

LCD --You're gunna need one. This is a 7" one I bought. I gotta tell ya, I am quite happy. It is clear and draws very little current but best yet, it comes with a "framed mount" that will snap into (and "trim-out") a retangular opening. It also comes with a very nice pedistal mount that has a double-sided sticky mount or can use screws. Viewing angle can be adjusted as well. Bottom line is that I got every penny of <$40 out of it. Good screen.

My second thought is of course video games... You know that the prop plays pole position, right? Tetris too! If I were stuck peddling to nowhere, I would want to be playing tetris at the time. This subject has been addressed before, people play "boxing/ chess" where they play rounds of chess between between rounds of beating the hell out of each other so the game/excercise theory is there!

Now, of course there are the Simpsons as well --There was an episode of the Simpsons where Homer was eating apple-flavoured (see I put the extra "u" in there for you) power-bars and getting ready to climb some sorta really tall moutain. During his training, a large Austrian trainer kept saying "You will lift the weights, I will shout inspirational slogans at you...    ...You can do it, feel the burn..." I think you can use the wav player to do the same thing. Why not find some voices (maybe your own or spouce's) and put together some "inspirational slogans" to be played whist riding?

If you are just trying to burn through some IO pins, why not just some data-logging for fun? An encoder on every sprocket, wheel and roller --Might be fun just to go through the data after you are done --Could you get a better/easier/harder/ more effecient workout if you had been in a different gear?


On a side note, I got the samples I ordered. They are 8 channel, 12-bit, i2c ADC chips. They are the smallest thing I have ever seen, I swear. I am in the process of trying to decipher the datasheets and the how the i2c protocal works. (I have sucessfully "spoken" to the chip and can read it, I am still having issues with the fact that I am getting a byte and a 1/2, instead of a 2 bytes or a full word) When I get this thing working, my goal is to produce a nice little ADC add-on for the Prop. --Right now there are some available but they are SPI and waste pins. Mine will be I2c and therefor will be sharing pins, the way it should be. When it is all up and running, and I get my pcb's back, I will be sure to pass a couple on to you.

I wish I still drank, and you were closer --I would love to simply sit down for a beer with you sometime and just listen to you talk... I swear, I love how your mind works. GodSpeed.


Thanks for the Mega amount of info (inc shout box chatter), i am much clearer on the direction to take.

The instructable lead was a cool link to a heap of retro games .... a list longer than my arm.

The games as you might of guessed did not work on my EasyProp board .... until i found out that you have to use pins 24,25,26 and change the timings of the prop...........then all was good and the screen jumped into full color ( colour without the "u" :-).

I still have to hack the mouse and keyboard as the EasyProp uses .....yes you guessed it pins 24,25,26,27 GrrrAhhh (no problemo hey)

The games are mega fast - the prop. is really under-rated.........

.....anyway i have almost gone through the whole list and now know what type of game would fit ........

..... mainly speed and altitude type games.........ie car racing and "Defender" scroll type visuals.

There are three rollers on my trainer but they are all synchronous so i would only have to encode one :-)

Measuring the spokes is the way i do it now (but just one spoke)....... if i used a laser (remote) and photo diode then you could monitor 36 spokes - this would give a faster response ..... i have not calculated the pulse width on one spoke ....but i am sure rik would help here.....

The other interactive idea (again shout box) which really appeals to me the the use of the static electricity build up produced in the Ether whilst using the darn roller.......it can be a problem and its not possible to use a radio next to the rollers because of this (hence the MP3/SID/WAV idea), Fritzls Spirit detector circuit would be able to measure the static ....and i have already the transistors in my pocket...and i have already build a 3D version (which i must blog at some time as well). The resulting signal could be sent to some bright "Mood" leds etcetcetc

Yes Training goals are a must to re:-motivational "Kicks" --- that push to accelerate and windup wind-down does re-leave the monotony

I am eager to see the 8 channel12bit analog interface card in action and for sure i would use one (provided it was "Rocket Brand").

Oh Yes to meet down the pub Chris would be "mind-boggling" - "we" are already drunk on too many brilliant ideas...

You know how Tetris speeds up as you progress through the levels? Make that speed interactive! The harder you work, the slower the Tetris gets, so you can get higher scores.

This could work on many games.

Pong peddle works harder as you are working harder.
More ammo to hoot the invaders.
More umphf to the pinball flippers.

The list is endless.

I have basically three ways of feeding-backing info (without interfering with general flow of things)

  •  acceleration and deceleration , and general speed ..... clocking the Wheel rotations
  • Cadence - a sensor which clocks the pedal rotations
  • Heart rate :- very important...if you overstep your heart rate your performance goes down...rapidly

Bike Fittness is a combo of the above ........

I like the trend of making things go slower the faster you go .... gives an incentive to go faster .....and not the carrot/donkey effect.