83 lines
3.3 KiB
C++
83 lines
3.3 KiB
C++
#include "nimble_distance_sensor.h"
|
|
|
|
namespace esphome
|
|
{
|
|
namespace nimble_distance
|
|
{
|
|
static const char *const TAG = "nimble_distance";
|
|
|
|
static int median_of_3(int a, int b, int c)
|
|
{
|
|
int the_max = std::max(std::max(a, b), c);
|
|
int the_min = std::min(std::min(a, b), c);
|
|
// unnecessarily clever code
|
|
int the_median = the_max ^ the_min ^ a ^ b ^ c;
|
|
return (the_median);
|
|
}
|
|
int NimbleDistanceSensor::get_1m_rssi(nimble_tracker::NimbleTrackerEvent *tracker_event)
|
|
{
|
|
return this->ref_rssi_; //+ tracker_event->getTXPower() + 99;
|
|
}
|
|
|
|
Filter::Filter(float fcmin, float beta, float dcutoff) : one_euro_{OneEuroFilter<float, unsigned long>(1, fcmin, beta, dcutoff)}
|
|
{
|
|
}
|
|
|
|
bool Filter::filter(float rssi)
|
|
{
|
|
Reading<float, unsigned long> inter1, inter2;
|
|
// TODO: should we take into consideration micro seconds (returned from esp_timer_get_time())
|
|
// vs mili seconds (implementation used in ESPresence?)
|
|
inter1.timestamp = esp_timer_get_time();
|
|
inter1.value = rssi;
|
|
|
|
return this->one_euro_.push(&inter1, &inter2) && this->diff_filter_.push(&inter2, &this->output);
|
|
}
|
|
|
|
void NimbleDistanceSensor::setup()
|
|
{
|
|
this->filter_ = new Filter(ONE_EURO_FCMIN, ONE_EURO_BETA, ONE_EURO_DCUTOFF);
|
|
}
|
|
|
|
// Defined distance formula using
|
|
// https://medium.com/beingcoders/convert-rssi-value-of-the-ble-bluetooth-low-energy-beacons-to-meters-63259f307283
|
|
// and copied a lot of code from
|
|
// https://github.com/ESPresense/ESPresense/blob/master/lib/BleFingerprint/BleFingerprint.cpp
|
|
bool NimbleDistanceSensor::update_state(nimble_tracker::NimbleTrackerEvent *tracker_event)
|
|
{
|
|
this->oldest_ = this->recent_;
|
|
this->recent_ = this->newest_;
|
|
this->newest_ = tracker_event->getRSSI();
|
|
this->rssi_ = median_of_3(this->oldest_, this->recent_, this->newest_);
|
|
|
|
float ratio = (this->get_1m_rssi(tracker_event) - this->rssi_) / (10.0f * this->absorption_);
|
|
float raw = std::pow(10, ratio);
|
|
|
|
if (!this->filter_->filter(raw))
|
|
{
|
|
ESP_LOGD(TAG, "Not enough data to calculate distance.");
|
|
return false;
|
|
}
|
|
|
|
auto max_distance = 16.0f;
|
|
if (max_distance > 0 && this->filter_->output.value.position > max_distance)
|
|
return false;
|
|
|
|
auto skip_distance = 0.5f;
|
|
auto skip_ms = 5000;
|
|
auto skip_micro_seconds = skip_ms * 1000;
|
|
auto now = esp_timer_get_time();
|
|
|
|
if ((abs(this->filter_->output.value.position - this->last_reported_position_) < skip_distance) && (this->last_reported_micro_seconds_ > 0) && ((now - this->last_reported_micro_seconds_) < skip_micro_seconds))
|
|
{
|
|
return false;
|
|
}
|
|
|
|
this->last_reported_micro_seconds_ = now;
|
|
this->last_reported_position_ = this->filter_->output.value.position;
|
|
this->publish_state(this->filter_->output.value.position);
|
|
return true;
|
|
}
|
|
} // namespace nimble_distance
|
|
|
|
} // namespace esphome
|