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https://github.com/mongoose-os-libs/apds9960-i2c

Mongoose OS library for APDS-9960
https://github.com/mongoose-os-libs/apds9960-i2c

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Mongoose OS library for APDS-9960

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README 

        
# APDS-960 I2C Driver



A Mongoose library for Avago's APDS-9960 RGB, IR and Gesture Sensor.



## Implementation details



The APDS-9960 device features advanced Gesture detection, Proximity detection,

Digital Ambient Light Sense (ALS) and Color Sense (RGBC). The slim modular

package, L 3.94 x W 2.36 x H 1.35 mm, incorporates an IR LED and factory

calibrated LED driver for drop-in compatibility with existing footprints.  



### Gesture detection



Gesture detection utilizes four directional photodiodes to sense reflected IR

energy (sourced by the integrated LED) to convert physical motion information

(i.e. velocity, direction and distance) to a digital information. The

architecture of the gesture engine features automatic activation (based on

Proximity engine results), ambient light subtraction, cross-talk cancelation,

dual 8-bit data converters, power saving inter-conversion delay, 32-dataset

FIFO, and interrupt driven I2C communication. The gesture engine accommodates

a wide range of mobile device gesturing requirements: simple UP-DOWN-RIGHT-LEFT

gestures or more complex gestures can be accurately sensed. Power consumption

and noise are minimized with adjustable IR LED timing.



### Proximity detection



The Proximity detection feature provides distance measurement (E.g. mobile

device screen to user’s ear) by photodiode detection of reflected IR energy

(sourced by the integrated LED). Detect/release events are interrupt driven,

and occur whenever proximity result crosses upper and/ or lower threshold

settings. The proximity engine features offset adjustment registers to

compensate for system offset caused by unwanted IR energy reflections

appearing at the sensor. The IR LED intensity is factory trimmed to eliminate

 the need for end-equipment calibration due to component variations. Proximity

 results are further improved by automatic ambient light subtraction.



### Color and ALS detection



The Color and ALS detection feature provides red, green, blue and clear light

intensity data. Each of the R, G, B, C channels have a UV and IR blocking

filter and a dedicated data converter producing16-bit data simultaneously. This

architecture allows applications to accurately measure ambient light and sense

color which enables devices to calculate color temperature and control display

backlight.



## API Description



There are two APIs defined in this driver. Firstly, a low level API is used to

drive the configuration of the chip. Secondly, a higher level abstraction is

provided for application programmers that want to merely read `proximity` and

`light` data from the sensor, or install a hardware interrupt to callback user

code upon certain events (such as `proximity`, `light` and `gesture` events

described above.)



### Notes



Gesture sending is incredibly hard with this sensor. Work is needed to improve

the performance of the gesture code in this driver.



Proximity and Light sensing and interrupts are working fine.



## Example application



An example program using a timer to read data from the sensor every 5 seconds:



```

#include "mgos.h"

#include "mgos_config.h"

#include "mgos_apds9960.h"



static void light_interrupt(uint16_t clear, uint16_t red, uint16_t green, uint16_t blue) {

  LOG(LL_INFO, ("clear=%u red=%u green=%u blue=%u", clear, red, green, blue));

}



static void proximity_interrupt(uint8_t proximity) {

  LOG(LL_INFO, ("proximity=%u", proximity));

}



static void apds9960_timer_cb(void *user_data) {

  struct mgos_apds9960 *sensor = (struct mgos_apds9960 *)user_data;

  uint16_t clear = 0, red = 0,  green = 0, blue = 0;

  uint8_t proximity = 0;



  if (!mgos_apds9960_read_light(sensor, &clear, &red, &green, &blue)) {

    LOG(LL_ERROR, ("Could not read APDS9960 light sensor"));

  }

  if (!mgos_apds9960_read_proximity(sensor, &proximity)) {

    LOG(LL_ERROR, ("Could not read APDS9960 proximity sensor"));

  }



  LOG(LL_INFO, ("clear=%u red=%u green=%u blue=%u proximity=%u", clear, red, green, blue, proximity));

}



enum mgos_app_init_result mgos_app_init(void) {

  struct mgos_apds9960 *sensor;



  sensor = mgos_apds9960_create(mgos_i2c_get_global(), mgos_sys_config_get_apds9960_i2caddr());

  if (!sensor) {

    LOG(LL_ERROR, ("Could not create APDS9960 sensor"));

    return false;

  }



  if (!mgos_apds9960_set_callback_light(sensor, 10, 1000, light_interrupt)) {

    LOG(LL_ERROR, ("Could not enable APDS9960 light callback"));

    return false;

  }



  if (!mgos_apds9960_set_callback_proximity(sensor, 0, 150, proximity_interrupt)) {

    LOG(LL_ERROR, ("Could not enable APDS9960 proximity callback"));

    return false;

  }



  mgos_set_timer(1000, true, apds9960_timer_cb, sensor);



  return MGOS_APP_INIT_SUCCESS;

}

```



# Disclaimer



This project is not an official Google project. It is not supported by Google

and Google specifically disclaims all warranties as to its quality,

merchantability, or fitness for a particular purpose.