PIR Motion Sensor

Device driver interface for the PIR motion sensor.

enum @151
PIR_OK = 0
everything went as expected
PIR_NOGPIO = -1
errors while initializing the GPIO
PIR_NOTHREAD = -2
errors while registering the thread
PIR_TIMEERR = -3
errors while getting the time information
enum pir_event_t
PIR_STATUS_ACTIVE = PIR_MSG_T_STATUS_START
motion was detected
PIR_STATUS_INACTIVE
no motion is detected
int pir_init(pir_t * dev, const pir_params_t * params)

Initialize a PIR motion sensor.

The PIR motion sensor is interfaced by a single GPIO pin, specified by gpio.

Note

The sensor needs up to a minute to settle down before meaningful measurements can be made.

Parameters

dev:device descriptor of an PIR sensor
params:parameters of the PIR sensor

Return values

  • 0 on success
  • -1 on error
pir.h::pir_event_t pir_get_status(const pir_t * dev)

Read the current status of the motion sensor.

Parameters

dev:device descriptor of the PIR motion sensor to read from

Return values

  • 1 if motion is detected, 0 otherwise
int pir_get_occupancy(pir_t * dev, int16_t * occup)

Read OCCUPANCY value.

Parameters

dev:device descriptor of the PIR motion sensor to read from
occup:occupancy ratio [in 100 * percentage] The value is renewed when it is read. So it is percentage of occupancy since the last read.

Return values

  • 0 on success,
  • -1 on errors,
int pir_register_thread(pir_t * dev)

Register a thread for notification whan state changes on the motion sensor.

Note

This configures the gpio device for interrupt driven operation.

Parameters

dev:device descriptor of the PIR motion sensor to register for

Return values

  • 0 on succuess,
  • -1 on internal errors,
  • -2 if another thread is registered already
PIR_MSG_T_STATUS_START

value to configure sensitivity of sensore 

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struct pir_params_t

Parameters needed for device initialization.

gpio.h::gpio_t gpio

GPIO device which is used.

bool active_high

Active when GPIO pin is high or not.

struct pir_t

device descriptor for a PIR sensor

uint64_t start_active_time

Time when PIR starts to be active.

uint64_t accum_active_time

Accumulated active time.

uint64_t last_read_time

Last time when PIR status is read.

kernel_types.h::kernel_pid_t msg_thread_pid

thread to msg on irq

bool active

Indicate PIR is active or not.

pir_params_t p

Configuration parameters.