this all sounds good to me. I’ll make the changes to generic_accel*
and the sensor API, unless somebody beats me to it.
Sterling
On 13 Dec 2016, at 6:10, David G. Simmons wrote:
+1 on the more 'generic' data types. With this, *any* sensor can
simply return a SENSOR_VALUE_TYPE_FLOAT_TRIPLET whereas if we use
SENSOR_VALUE_TYPE_MS2_TRIPLET then a sensor that wants to return a
float triplet that ISN'T M/s^2 would either have to define its own
data type or would use a rather confusing data type. And even if a
sensor DID want to define it's own data type, it could simple be
#define MY_SENSOR_FLOAT_TRIPLET SENSOR_VALUE_TYPE_FLOAT_TRIPLET
It's probably worth discussing a bit whether float or int32_t (with a
different scale like mm/s^2) are better.
There is (unsurprisingly!) no support for %d in tinyprintf, for example:
https://github.com/apache/incubator-mynewt-core/blob/develop/libc/baselibc/src/tinyprintf.c
Personally, I got over my allergic reaction to float many years ago, but
I do understand the valid concerns around it both in terms of precision,
code size and ease of use.
My vote is to stick to standard units like uTesla (mag), m/s^2 (accel),
rad/s (gyro), which necessitate floats. I just think those are more
natural data types and you can convert any sensor output to those units
to have comparable, HW nuetral values from any accel/mag/gyro/whatever.
That probably means adding a compile time flag for %f support and
support in tonyprintf (which will be less tiny).
But if we do want to stick to int32_t, while still using standard SI
values, we'll need to adjust the scale and move away from the units you
generally encounter in the real world, and perhaps lose a bit of
precision return int32_t mm/s^2, or um/s^2, etc.
This won't work today though:
if (ctx->type == SENSOR_TYPE_ACCELEROMETER) {
sad = (struct sensor_accel_data *) data;
if (sad->sad_x != SENSOR_ACCEL_DATA_UNUSED) {
console_printf("x = %f, ", sad->sad_x);
}
if (sad->sad_y != SENSOR_ACCEL_DATA_UNUSED) {
console_printf("y = %f, ", sad->sad_y);
}
if (sad->sad_z != SENSOR_ACCEL_DATA_UNUSED) {
console_printf("z = %f", sad->sad_z);
}
console_printf("\n");
}
Kevin
