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How To: PIR Module

The PIR module is mostly used as a motion detector. Thanks to its low power consumption it can safely be used with batteries acting as the only power source.

References

Sensitivity

SDK offers you four types of sensitivity defined as enum type, so you can use simple names:

  • TWR_MODULE_PIR_SENSITIVITY_LOW
  • TWR_MODULE_PIR_SENSITIVITY_MEDIUM
  • TWR_MODULE_PIR_SENSITIVITY_HIGH
  • TWR_MODULE_PIR_SENSITIVITY_VERY_HIGH

It is very hard to predict how exactly the PIR sensor will act in your particular use case, it is always a good idea to test every type of sensitivity to find out which one to use for the best results.

Example

info

This example uses Medium sensitivity. When movement is detected, the message Movement! is sent to your computer via USB.

Motion Detection Code Example

#include <application.h>twr_module_pir_t pir;twr_button_t button;void pir_event_handler(twr_module_pir_t *self, twr_module_pir_event_t event, void *event_param){    (void) self;    (void) event_param;    if (event == TWR_MODULE_PIR_EVENT_MOTION)    {        twr_log_debug("Movement detected!");    }}void application_init(void){    twr_log_init(TWR_LOG_LEVEL_DEBUG, TWR_LOG_TIMESTAMP_ABS);    twr_module_pir_init(&pir);    twr_module_pir_set_sensitivity(&pir, TWR_MODULE_PIR_SENSITIVITY_MEDIUM);    twr_module_pir_set_event_handler(&pir, pir_event_handler, NULL);}