On Sun, May 22, 2011 at 4:22 PM, Olin Lathrop w= rote: > Mark Rages wrote: >> I took apart a PowerTap to have a look. =A0It has four gages arranged >> around the outside of a torque tube. =A0(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.) =A0The microprocessor is a >> PIC16F690. =A0I would not be surprised if some of Olin's code is still >> running in there. > > That means you have one of the original PowerTaps. =A0the 16F690 code was > written by another PIC consultant, Dave Hoch. =A0If you dig around some m= ore > you'll find another processor, a 16F628. =A0I 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. =A0The 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. =A0It 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(?). =A0The original engi= neers > 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 loo= ks > like today. > The hub I took apart was one of the more recent ANT+ ones. It has only the 16F690 in there, and a traditional diff amp -> ADC arrangement. Maybe the handlebar computer uses an MSP430. Yes, PowerTap is in Wisconsin. I've met some of their engineers at trade shows. They seem like sharp guys. (BTW, interesting live event at quarq.com right now) Regards, Mark markrages@gmail --=20 Mark Rages, Engineer Midwest Telecine LLC markrages@midwesttelecine.com --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .