Hacking the Proform le Tour de France exercise bike. Zwift connection.

Emulating a smart trainer

Now we have the codes that the Proform bike sends from the console to the lower control board.  It is time to connect the bike to a fitness program using bluetooth low energy (|BLE).

Normally I'd use an Arduino for this type of real time project, but most Arduinos don't have bluetooth. I'd contemplated using a Raspberry Pi for the bluetooth, but it might be overkill.  Luckily, someone introduced me to the ESP32 boards and after a virtual trip to Digikey I am now a proud owner of a Seeed Studios XIAO ESP32C3 (hereafter known as ESP32).  Bluetooth, wifi, loads of ram and flash, decent IO pins and only $7.66 from Digikey.  Amazing.  AMAZING. (so many projects beckon...)

I'd looked at BLE fitness protocols before and honestly, the documents are as dry as hay and less informative.  Previously I made a pseudo-smart exercise bike with a stepper motor and bluetooth was so confusing that I just went for ANT+ on a Raspberry Pi.

Luckily, this time I was able to find some code from others that had successfully used bluetooth.  The BLE code was reused from a project by Gene's Green Machine. His Zwift connected exercise bike instructable:
https://www.instructables.com/Zwift-Capable-Pedal-Generator/. Great projects, I adapted the code to fit the Proform situation.  This really helped me start sending data from the Proform bike via bluetooth.

In a nutshell, the ESP will calculate power based on resistance settings and current cadence.  Power is torque times angular velocity -- ie resistance times load.  The ESP32 also receive values for incline and sends these along to the Proform to adjust the resistance level accordingly to simulate riding up or down hills.

The power calculation was a tricky thing.  Initially I "injected" cadence values to the console and then noted the power calculated at each gear level (0 to 26).  I then empirically determined a second order polynomial formula that closely calculated power to those provided by the bike.  The formula works best at cadence values 60 to 100.  I didn't spend a lot of time massaging the calculation because I intend to better calculate the true power at different resistance levels and speeds using an old treadmill motor. Stay tuned.

 

The ESP takes input from 4 buttons allowing a the ride to change gears - the bike simulates shifting (by changing resistance). I've programmed 3 front gear ranges and 11 rear ranges. The buttons shift the front rings up or down and the rear cassette up or down. The ESP also gets incline values from Zwift and converts them to resistance settings. The bike seems to have about 128 resistance settings. Zwift goes from 0 to 15 degrees incline so initially I had 8 steps of resistance per degree of incline - -this was absolutely BRUTAL so I dialed it back to 4 steps per degree.

The ESP will also take the Zwift incline and set the tilt of the bike based on the Zwift numbers. The incline changes often so I found the clunking of the tilt annoying and disabled it in my current running code.  All the data is communicated to the bike via RS485 using the original codes and protocol of the Proform bike.  To wire in the ESP32 and avoid conflicts, I disconnected the console from the lower control board to add the ESP32. So the console no longer displays power, gears, time, etc.

I've been using the ESP32 setup to successfully to connect and ride in Zwift. I've uploaded some code and a schematic to Github.
https://github.com/kevinmott09/proformBLE

Next on the TO DO is add an ERG mode and also firm up the real power numbers of the bike.  And also get the setup off the breadboard and tidily tucked away into the bike somewhere.

 

Proform Tour de France Exercise bike

I bought a used Proform Tour de France exercise bike to replace a homemade version exercise bike.  Not knowing much about it I decided to take a leap of faith for the low used price of $400CAD (regular $1999?).  

Proform Le Tour de France exercise bike.

I'm pleasantly surprised by the quality of the bike.  It seems sturdily built and allows very high resistance settings, something missing from my last bike.  It is very quiet when pedaling owing to its magnetic resistance, belt drive and narrow flywheel.  It has a nice incline function to enhance the experience, so I feel like I am actually going up a hill (or down).  Thankfully, it was in good condition and nothing was broken. 

The first task was to replace the seat.  I comes with a wide seat on a non standard mounting system.  So, I found a similar shaped rectangle of steel and welded on a length of scrap seatpost I had salvaged from an old bike. 

The other negative to me is the handlebars that came with the bike.  Very "gym" bike style -- my preference is for some nice road drop handlebars, but with the integrated incline and gear buttons, their replacement will be a bit more work.

My first few rides have been, well, a bit boring. I watch TV and try to keep my heart rate up for the duration.  But it leaves me wanting more and I think the capabilities of the bike are not fully exploited.  The bike has some Tempo and Interval Apps. But it seems all they do is set some targets for your watt output.  And you can program interval training limits into the bike too, but again it seems a bit simple.  There is a Bluetooth connection that allows the use of an iFit app but I'm not really up for the monthly subscription.  And it seems the iFit app is a bit like watching a movie of a bike ride.  It doesn't really take into account the effort you put into the workout.  

So, what to do with the bike? Can it be connected to Zwift? Could I write my own simple workouts for the bike?  Maybe upload a GPS file of my favorite ride? It might be time to look inside and see what makes it all tick.

Hacking the exercise bike