I bought a Water Rower rowing machine many years ago to train for a charity cycle ride. It is a great machine in many ways, ideal for home use due to it being quiet during use and the timber frame makes it look a more natural fit for the home.
My model has the Series IV Performance Monitor - basically a small computer that can tell you the usual stats on how you are performing, as well as reading data from the integrated Polar heart rate monitor.
However, the only option for storing this data is to connect the device via a propriatary cable (standard DB9 connector on computer end, a DIN connector on the rowing machine end) to a laptop running some propriatary (and poorly supported) software. My main computer at home is a Mac, so it is very hard to find a decent DB9:USB adaptor (many just don't work, some require installing kernal drivers that are too flaky to want to use); wireless would be ideal but there aren't any standard options for this.
So this project meets the following aims:
The project is working fully, though there is plenty of improvements that could be made! Using it more would be the biggest single improvement I could make :)
I have various python scripts to handle receiving the bluetooth data stream for live sessions and replayed sessions, as well as updating the clock on the device and testing the various modules. I also have scripts to create data for upload to RunKeeper (requires a faked .gpx GPS data file amongst other things).
Update: actually things are totally broken at the moment :( I had to borrow the Arduino and Bluetooth modules for another project and, thanks to a dodgy power supply module from China, those parts are now dead. Replacements are ordered so hopefully I'll be back to rowing soon!
I don't have any photos of the fully working system, unfortunately. Here are some progress shots I do have..
Bring-up of the graphical display. Boot screen working as expected, with date/time from RTC, but with extra output when I was trying to figure out how much screen real estate I had to work with!
The full system, powered by USB battery, with the DIN connector terminated cable to connect to the Water Rower's Performance Monitor.
Close up, showing the Bluetooth module (left hanging off), display (front, perpendicular to board), RTC and battery (top right), MAX3232 RS232 to TTL adaptor (top left, partially obscured by cable).
Sample output from RunKeeper - this is the goal of the project so I get lots of data to stare at! The faked GPS data started on the west coast of Ireland, and had me rowing directly west. I picked one of the earliest rowing sessions because otherwise the map would just be a small line in a (literal) sea of blue!