Hello All,

I will be taking over SensorAPI stuff from Sterling. 

Kevin:
TSL2561 Driver and LSM303 Driver that you have implemented are pretty good and 
I used both of them. I saw the values coming in using the SensorAPI. I would 
also like to understand about sensors from you or anybody else that is more 
experienced on these as I am kind of new to it, I have some experience but not 
a lot to get a generic understanding.

I am analyzing the API currently along with looking at LSM and TSL 
simultaneously to figure out if we need to add something that is missing to the 
API. I had a few questions:

About LSM303:

* Are +-1g values orientation values or is that actual acceleration ?
* Should we be separating out acceleration from orientation(maybe in 
get_interface()?)
* Zero-g level offset (TyOff) is the standard deviation of the actual output 
signal of a sensor from the ideal output signal. Should we be thinking of 
calibration for sensors in the SensorAPI ? I think in this case it comes with 
factory calibrated values which can be used by a developer. But that will 
change once put on a PCB, hence the concern.
* Operating mode of Sensors. Low Power mode Vs Normal Mode for Accelerometer 
and Sleep Mode Vs Single Conversion Mode Vs Continuous Conversion Mode. Modes 
should also be a part of our SensorAPI I believe.
*  Should the Filter mode selection also be part of the SensorAPI ?
* FIFO config and overrun interrupts and their need in the SensorAPI ? 
* How are accelerometers and magnetometers generally used ? In an interrupt 
based fashion where the thresholds are specified and then the values are read 
in an ISR or is it more of a polling based architecture where the sensors would 
be sampled at a given rate ?

About TSL2561:

* How are OLED sensors generally used ? In an interrupt based fashion where the 
thresholds are specified and then the values are read in an ISR or is it more 
of a polling based architecture where the sensors would be sampled at a given 
rate ? 
* The lux calculation function that is part of the Adafruit library does a 
great job at converting the values. The TAO data sheet for the sensor has the 
same function and it is recommended to use the same without any changes. I have 
used that for converting the values, changed the indentation to match Apache 
Mynewt’s coding style. 

I might have some more questions with regards to TSL2561. 

So far it looks like the SensorAPI does a great job apart from the above stuff.

If anybody has any suggestions, please feel free to chime in. 

Currently, it’s WIP and on its own branch, sensors_branch.

Regards,
Vipul Rahane

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