Electrical pulses -> Computer

[se7entse7en]

Looking for ideas.

I want to keep track of and store the 'speed' of my bike when I'm on the trainer. ('Speed' is in quotes 'cause I'm on the trainer and not actually going anywhere). I have a speedometer that keeps track of the speed in real time by detecting electrical pulses sent by a transducer, but it doesn't store the speeds.

My first thought was to write a usb driver to read these pulses and record the speed on my laptop. Kinda sounded like a lot of trouble, if not impossible, though. Then I thought about getting a USB->Serial Port and reading the pulses from the serial port. Sounded a bit more feasible but still a bit of work. I've never tried reading from the serial port like this before.

I also thought about sending the pulses to the headphone jack and recording the pulses as wav/wma/whatever, then writing a parsing routine (somehow) to detect the pulses... etc. Sounds possible but is there a better/easier way?

Then I thought about sending the pulses to a heartrate monitor which would then send the data to my gps watch which I could then upload to my laptop and repurpose. The hrm is $50-80 though, and I'm cheap. Also, there's a chance that there's some internal filtering algorithm in the watch to discount pulses outside of the range of a heartrate, whereas I'd need it to stay functional up to about 480 'bpm'.

Anybody have any suggestions for a cheaper alternative or any other ideas?

[nature boy]

wouldn't there be an actual device premade for your exact situation? i would imagine there would be. maybe talking to the shop where you got your trainer from?

[se7entse7en]

Not that I could see. Most seem to work the same way as my current one does. They read out your speed/cadence/distance/etc in real-time, but don't store the data. Some of the fancier ones might, but I'm not about to fork over $250+.

[nature boy]

that sucks.
if only we could find some sort of hub full of programmers both by vocation and hobbyists alike, in which you could ask this question.
now WHERE could we find such a place???

[se7entse7en]

Umm... about half of us ARE programmers.
Also, I wasn't necessarily asking a programming question. Just looking for ideas from an 'outside the box' perspective. To be honest, I'd say that most of you are all into gadgets more than even I am. Just thought you may be aware of some cheap gadget that could possibly be adapted to my needs.

[geForce]

Does your training bike have an actual wheel that spins when you pedal?

[se7entse7en]

Yes. My training bike is my bike setup on a trainer which elevates the rear wheel and has a roller pressed up against it which turns impellors in a fluid filled chamber in order to provide resistance.

I have a small magnet attached to the spokes which passes through a coil generating a small electrical pulse every time the wheel turns. This is how my current speedometer works. It calculates the speed based on the frequency of the pulses and displays it. It does not, however, store the speeds for later analysis.

[geForce]

Actually, how about this?
http://www.instructables.com/id/Very-Ea ... r-Bike-12/

[geForce]

Oh, haha.. that's exactly what you have.

[geForce]

Hmm, actually, the link says this one records max and avg times. Would that be good enough for you? Or did you want some more detailed records?

[se7entse7en]

That's pretty much what my current speedometer does. I want more detailed data on speed fluctuations.

This, and the like, will do what I want: http://www.amazon.com/Garmin-Cycling-Ca ... 00+cadence

But I'm not about to pay $350 for anything right now except maybe a plane ticket home.

[nature boy]

i'm wondering now... why do you want to store the speeds? are you hoping to get an average speed over time that you're biking? i'm just wondering because if that were the case, wouldn't it be just possible to write down whatever information you wanted to store after the fact?

[se7entse7en]

It's about knowing how much time is spent working out in the various workout zones. Average speed alone is not a good indicator of the difficulty of a workout. Biking at 35 km/h for an hour is a good workout. Doing repeats of one minute on, one minute off for an hour at 70 km/h is not humanly possible. Both would have you averaging 35 km/h.

[nature boy]

Forgive my ignorance, but wouldn't you want to intentionally train in certain areas for certain periods of time? Like, if you wanted to train at 35kmh for an hour, wouldn't your current device and a stopwatch tell you if you did or not?
I'm not trying to retract from your original question, but i'm just wondering if there is a simple work around to get what you're after.

[se7entse7en]

Here's a relatively straight forward workout:

5 minute warm-up rest= false

3x
30 second Hard rest= false
30 second Easy rest= true

2 minutes Easy rest= true

10x
20 seconds high cadence rest= false
10 seconds REST rest= true

3 minutes REST rest= true

9x
90 second threshold intervals rest= false
30 second REST rest= true

2 minute REST rest= true

60 second Progressive Tempo (52/19) rest= false
60 second Progressive Tempo (52/17) rest= false
60 second Progressive Tempo (52/17) rest= false
60 second Progressive Tempo (52/15) rest= false
60 second Progressive Tempo (52/13) rest= false

3 minute REST rest= true

3x
Sprint Phase 1 Tempo (52/15) rest= false
Sprint Phase 2 Recovery (52/13) rest= true
Sprint Phase 3 ALL OUT (52/13) rest= false
60 second REST rest= true

5 minute cool-down rest= true

It's a bit much to try and remember how hard you were able to perform each of the various intervals. It's hard enough to remember your own name.

Anyway... I think I'm going to just bite the bullet, spend the money, and do it right.