Skip to main content

Computrainer Update

Edit: Breaking news 20th October - I now have it coded into Golden Cheetah. The gui is a basic set of LCD numbers (rather like the display on a Garmin 705 in fact). Next steps are to add saving data to disk and a real-time scrolling graph!

To explain the video I start Golden Cheetah, show some of the features then start a realtime session, get on my bike, ride stop and then get back to my PC and stop the session. The 5 numbers are power, cadence, heartate, speed and load. I start with a load of 100w and then you will see it go up to 200w or so and then back down again. I am controlling this using the +/- keys on the unit.

Edit: Breaking news 11th October - I now have outbound control and inbound telemetry working . I can sit on my turbo and set load up and down with the +/- keys and watch watts cadence et al. Its all very ghetto, with just a console mode, but I can now set about turning it into something pretty with graphs etc.

For those of you that are interested I have opened up a sourceforge project to host my documentation and a sample utility to implement the key features. I've put the first draft of my documentation there for now, over the coming weeks I'll drop some code in there too.

Obviously my longer term goal is to put a real-time mode into Golden Cheetah. I'm making pretty good progress towards my goal of having something usable by 2010... Even if I have been tempted to take it apart in an attempt to 'understand it better' :-)

The above was taken in an attempt to work out what chips it uses to try and understand some of the bizarre memory structures.

And this little lad helped me along the way. Bless him, he is more than happy to sit and churn over the gears to help his old man. I'm sure that'll change over the next few years - so I'd better enjoy it whilst I can!

I can now read telemetry and set load on my CT. I haven't sorted out spin-scan or LTA etc. But frankly they're gimmicks. Still reckon that I'll get the Computrainer working on my Macbook before 2010.

I needed help generating load whilst I fiddled with my software ... above is a picture of my guineau pig in action.

Thanks Oli!

Popular posts from this blog

W'bal its implementation and optimisation

So, the implementation of W'bal in GoldenCheetah has been a bit of a challenge.

The Science I wanted to explain what we've done and how it works in this blog post, but realised that first I need to explain the science behind W'bal, W' and CP.

W' and CP How hard can you go, in watts, for half an hour is going to be very different to how hard you can go for say, 20 seconds. And then thinking about how hard you can go for a very long time will be different again. But when it comes to reviewing and tracking changes in your performance and planning future workouts you quickly realise how useful it is to have a good understanding of your own limits.

In 1965 two scientists Monod and Scherrer presented a ‘Critical Power Model’ where the Critical Power of a muscle is defined as ‘the maximum rate of work that it can keep up for a very long time without fatigue’. They also proposed an ‘energy store’ (later to be termed W’, pronounced double-ewe-prime) that represented a finit…

Polarized Training a Dialectic

Below, in the spirit of the great continental philosophers, is a dialectic that attempts to synthesize the typical arguments that arise when debating a polarized training approach.

It is not intended to serve as an introduction to Polarized training, there are many of those in-print and online. I think that Joe Friel's blog post is a good intro for us amateurs.

For Synthesis Against A Elite athletes have been shown in a number of studies to train in a polarized manner [1][2][3] There is more than one way to skin a cat. Elite athletes adopt plans that include high-volumes of low intensity and low-volumes of high-intensity. Elite athletes have also been shown to train in a pyramidical manner
[13] B Polarized Zones are between LT1/VT1 and LT2/VT2 [1]
LT1/VT1 and LT2/VT2 can be identified using a number of field based approaches [4][5][6][7]

You can follow guidelines on mapping LT1/LT2 to cycling power to make it useful for amateur cyclists. Polarized zones are har…

W'bal optimisation by a mathematician !

So the integral computation for W'bal was expensive.

I tried to optimise from a domain and  programming perspective, where Dave Waterworth, a mathematician found a much more elegant and fast reformulation.

This means W'bal can EASILY be computed as you ride.

To explain the math here are his words;

I posted a comment on you Blog post on optimising the Wbal model. I've done some more thinking and I defn think it can be done without visiting the previous samples as the Skiba formula can be decomposed further, i.e. From your blog I believe the integral part of the equation is:

Basically this takes a weighted sum of preceding W'exp samples where the weight decays at a rate determined by tau, older samples are weighted less than newer ones. We can approximate as a sum provided tau is large compared to Ts (the sample rate):

Basic properties of exponential functions allow the for…