I want to build a cycling computer with a view to a specific discipline of cycling, BMX racing.
it is for my daughter to work on training, I have been shopping and cant find anything that covers what I want.
So with very minimal Arduino knowledge I believe this is a project I might take on.
first what is needed, two sensors, simple sounding...
magnet on the pedal passes a sensor on the frame.
another magnet on the wheel passes a sensor on the frame.
many cycle computers use this layout, its common.
now what is needed in the end:
peak Cadence
average cadence
peak speed
average speed.
total pedal strokes
this would be by session.
a reset button at the riders disposal would mark the beginning of a new session.
the clock/counter would start at the first pass of the pedal sensor or wheel sensor and stop when the bike passes the finish line.
how can the finish line be sensed?
perhaps a wifi data collector could be added so a laptop would log each session/lap
after each lap the rider could view the last output on the laptop screen likely setup at the starting hill, then load up in the gate, press the button, and start a new lap/session trying to better the numbers.
no screen needed on the Arduino, and hopefully a really small simple one could do all this.
After a little rethink, to overcome the finish line issue another wireless box that used optic reflector type sensor like in alarm cross the beam systems.
this would communicate with the laptop and then allow for final lap time as well.
Yes, it's just two pulse counters and a bit of maths. I have never heard of two counter systems on one Arduino but, in the unlikely event it can't be done, it just means using two Arduinos.
I imagine your only problem would be real-time communication but on-board recording for recovery at the end of a session should be all you need, and easily accomplished.
I'm surprised such a device doesn't already exist.
Nick_Pyner:
I'm surprised such a device doesn't already exist.
so am I, the total pedal strokes is the most important part of it.
all the cycling computer setups so far are engineered for either MTB or road discipline. The few that have BMX in mind miss the total pedal rotation count, its a sprint sport to the finish line so that is of extreme priority during training.
is there a forum or a location where hobbyists might assist me as I am quite a newb with Arduino.
I am looking at the Arduino Nano at Hobbyking as the foundation of this.
I am thinking of using this on the bike with a wifi and two more, one at finish line with a wifi board and one attached to the laptop with the other wifi board directly talking to each other. perhaps the one on the bike could use Bluetooth to connect to the laptop and offload the data logged from the onboard unit.
I have discovered the gate control unit has a connection for timing computer that can be used to trigger the laptop controller to start the lap.
on the finish line unit to end the lap.
still working out how to get the finish line unit to trigger a stop on the onboard bike counter when its communicating with the start line unit.
If there was a place near the finish line where they must shift, that can be measured with the data you are already collecting. Although you won't know where the exact line is, since it's usually a straight section, at least you know how to divide the data into equal laps. This can be done manually at the end of the race when you look at the data. The rest can happen in real time?
Just read your initial post again. You said they'd stop after each lap to look at the data. So why wouldn't my first idea work? Simply stop pedaling at the finish line for 5 seconds. That's when you stop counting.