Swim Lap Counter

[harpo666]

Hi guys,.

I am trying to build a swim lap counter.

Any suggestions as to the best way to use the accelerometer to identify when a swimmer has turned and a lap is complete?

Thanks.

[JonFitbit]

Depending on which device you're using, if it has a gyroscope, that's the preferred way. 

https://dev.fitbit.com/build/guides/sensors/gyroscope/

Note: Only the Fitbit Ionic, Fitbit Versa, and Fitbit Sense contain a gyroscope sensor.

 

[harpo666]

Thanks Jon!

For the Versa 3 and Versa 2, how would you approach detecting a lap (change in direction) without the gyroscope?

[JonFitbit]

I think you'll need to do some research into the algorithms required when using an accelerometer to simulate a gyroscope.

https://electronics.stackexchange.com/questions/205644/simulate-gyroscope-through-mems-accelerometer

Another approach would be to record some data and plot it on a graph so you can see how the sensor is behaving during a swim.

https://dev.fitbit.com/build/guides/sensors/accelerometer/

[harpo666]

Great, thanks for those ideas on using an accelerometer Jon.

[AdisP]

@JonFitbit any update on the introduction of lap counting while swimming on Charge 4? As I understood this feature is also missing on the Versa 4 and Sense.

[JonFitbit]

@AdisP probably best to ask in the Charge4 forum.

[AdisP]

@JonFitbit I am asking for all three devices since I got informatiin from the FitBit support that it is in the making.

[AdisP]

And why was lap count feature excluded from Versa 3 when it was available on Versa 2? 

[JonFitbit]

I'd recommend asking in the product forums, this is the developer forum.