Footpod pace as data field

Does the Connect IQ SDK allow access to pace from an ANT+ footpod? If so, should be relatively easy to create a data field and address all of those GPS pace concerns ;)

If not, implementation in a future SDK version seems a quick fix for Garmin to implement footpod pace across all Connect IQ watches?

1) Low level ANT+ access. Maybe likely. But u will need to build entire app to support its usage.
2) current datafield can access footpod but footpod cadence and accelerometer cadence is same. (Also for foot pod I believe) - I did some testing.

Pace isn't directly accessible as a raw value, but a foot pod will provide you with your cadence (steps/min) and instantaneous distance (m/s). From that, you can calculate your pace.

Thanks both, but still bit confused.

Instantaneous distance seems a strange measure, and m/s rather implies instantaneous speed. If instantaneous speed is accessible (even when GPS is activated), then this of course can be used to calculate pace.

Not sure how cadence can help? This page shows that speed should be accessible from the ANT+ profile http://www.thisisant.com/developer/ant-plus/device-profiles#528_tab

I'm not sure how much you know about this stuff, so please don't think I'm talking down to you...

Instantaneous distance seems a strange measure, and m/s rather implies instantaneous speed.

There is no such thing as instantaneous pace when given discrete position inputs as provided by GPS. Pace is calculated as the change in position over time, so you need at least two position and time points

Disance = (Position1 - Position0); // during the time period Time0 to Time1
Time = (Time1 - Time0);
Velocity = Distance / Time;


If instantaneous speed is accessible (even when GPS is activated), then this of course can be used to calculate pace.

Pace (Time / Distance) is just the inverse of speed (Distance / Time). Given that

Not sure how cadence can help?

It is just another way to calculate speed. If you have a good approximation of stride length, the number of steps, and the elapsed time, you can calculate speed as...

Disance = (StrideLength * Strides); // during the time period Time0 to Time1
Time = (Time1 - Time0);
Velocity = Distance / Time;


This page shows that speed should be accessible from the ANT+ profile http://www.thisisant.com/developer/ant-plus/device-profiles#528_tab

Yes, it is going to be available via ANT+, but the ANT+ functionality is not available to data fields (only watch-app and widget application types).

Travis

Thanks for the reply. Some comments

There is no such thing as instantaneous pace when given discrete position inputs as provided by GPS. Pace is calculated as the change in position over time, so you need at least two position and time points

Yes, that is clear. In this case though, I am referring to the footpod data, not GPS data. Brandon.ConnectIQ stated that instantaneous distance (m/s) is accessible from the pod. My comment was just that this is a speed metric, not distance.

If you have a good approximation of stride length, the number of steps, and the elapsed time, you can calculate speed as...

Sure - understand that with stride length you can calculate speed. But normally the footpod is calibrated with a multiplication factor in sensor settings (presumably modifying a default stride length) and then the API should provide a speed/distance based on this calibration.

Essentially, I would expect to be able to read a footpod speed metric through the Connect IQ API, regardless of whether GPS is activated or not. Then you could create a data field with this metric.

The point of my original post was that, if Garmin allowed such access through Connect IQ, they would not have to build such a metric natively into every watch with GPS pace issues (all MediaTek chipset watches).

Correct me if understanding is wrong.

footpod cad = spm
spm * stride length = meter / min
do some calculation and that should get equivalent in Speed or Pace.

Should it not?

Yes.

If you read cadence from the sensor, then multiplying that by stride length (and possibly a calibration factor), you'd get speed. I haven't looked at the ANT+ foot pod profile spec, but I'm almost certain that you are right; it would provide cadence.

That cadence value is not likely to be instantaneous though. It is very likely to be calculated as the number of strides in a given time, which is still not instantaneous because it is based on two discrete measurements. Of course, it could measure the amount of time between steps, in which case it would be instantaneous place, but only for the last step, not the current one.

Correct me if understanding is wrong.

footpod cad = spm
spm * stride length = meter / min
do some calculation and that should get equivalent in Speed or Pace.

Should it not?

Hello Nikeow,

Yes....but remember that the footpod only measures the movement of one(1) foot(leg).
Stride length for the footpod is for two(2) steps so if you cover 0.75m in one step then your stride length for the footpod is 1.5m :)

Again, none of this conversation even matters because the Toybox.Ant module is not accessible to data fields. In order for this to be useful you'd have to write a watch-app or widget.

Hello Nikeow,

Yes....but remember that the footpod only measures the movement of one(1) foot(leg).
Stride length for the footpod is for two(2) steps so if you cover 0.75m in one step then your stride length for the footpod is 1.5m :)

Yes.. it's multiplied by 2 in the output for the cadence field. There is a calibration factor, but supposedly the calibration factor for the internal accelerometer (F3 / 920 etc) are not available for usage by CIQ. However, having said that, even tho footpad calibration factor is available - I understand that it does not work (from reading the forums and pal's feedback)

Again, none of this conversation even matters because the Toybox.Ant module is not accessible to data fields. In order for this to be useful you'd have to write a watch-app or widget.

I'm still thinking - why there is a need to get access to the ANT module. There clearly is something which I am missing here.
for whatever is worth, the cadence field is actually a combination of external footpad and internal accelerometer. Is this the problem / issue that you are referring to?

Cos, when i tested it ( and I believe CIQ guys confirmed it) that footpad and accelerometer both provides the same data. (Can;t locate the forum posting for that.. yet)
I think this would be coming full circle to the feedback i've been seeing about external tempe support vs the internal temp sensor. (When connection to tempe is flaky, it will default to the internal temp sensor and then you suddenly see a 4-10c (making up this number) increase in the temperature due to skin contact and what not)

so, that may be the thing that you, travis, is referring to?