Mark Rages wrote:
> I took apart a PowerTap to have a look.  It has four gages arranged
> around the outside of a torque tube.  (The torque is transmitted from
> the right (drive) side to the left, and the wheel is actually driven
> from the left side of the bicycle.)  The microprocessor is a
> PIC16F690.  I would not be surprised if some of Olin's code is still
> running in there.

That means you have one of the original PowerTaps.  the 16F690 code was
written by another PIC consultant, Dave Hoch.  If you dig around some more
you'll find another processor, a 16F628.  I wrote the code for that one.
The two major things that processor does is interpret the very noisy data
from the heart rate monitor, and upload ride data over a software UART
interface.  The software UART was pretty tricky since the processor is only
running from a 160 kHz crystal and the baud rate is 9600.

I also wrote the original host code to receive the upload data.  It got run
implicitly under the hood by the user-visible apps.

When Graber bought the product line, they redesigned the hardware to use a
MSP430 and used their own engineers in Wisconsin(?).  The original engineer=
s
from the Boston area then no longer had anything to do with the project.
That happened around 10 years ago, so I have no idea what the product looks
like today.


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