esphome/esphome/components/hrxl_maxsonar_wr/hrxl_maxsonar_wr.cpp

66 lines
2.3 KiB
C++

// Official Datasheet:
// https://www.maxbotix.com/documents/HRXL-MaxSonar-WR_Datasheet.pdf
//
// This implementation is designed to work with the TTL Versions of the
// MaxBotix HRXL MaxSonar WR sensor series. The sensor's TTL Pin (5) should be
// wired to one of the ESP's input pins and configured as uart rx_pin.
#include "hrxl_maxsonar_wr.h"
#include "esphome/core/log.h"
namespace esphome {
namespace hrxl_maxsonar_wr {
static const char *const TAG = "hrxl.maxsonar.wr.sensor";
static const uint8_t ASCII_CR = 0x0D;
static const uint8_t ASCII_NBSP = 0xFF;
static const int MAX_DATA_LENGTH_BYTES = 6;
/**
* The sensor outputs something like "R1234\r" at a fixed rate of 6 Hz. Where
* 1234 means a distance of 1,234 m.
*/
void HrxlMaxsonarWrComponent::loop() {
uint8_t data;
while (this->available() > 0) {
if (this->read_byte(&data)) {
buffer_ += (char) data;
this->check_buffer_();
}
}
}
void HrxlMaxsonarWrComponent::check_buffer_() {
// The sensor seems to inject a rogue ASCII 255 byte from time to time. Get rid of that.
if (this->buffer_.back() == static_cast<char>(ASCII_NBSP)) {
this->buffer_.pop_back();
return;
}
// Stop reading at ASCII_CR. Also prevent the buffer from growing
// indefinitely if no ASCII_CR is received after MAX_DATA_LENGTH_BYTES.
if (this->buffer_.back() == static_cast<char>(ASCII_CR) || this->buffer_.length() >= MAX_DATA_LENGTH_BYTES) {
ESP_LOGV(TAG, "Read from serial: %s", this->buffer_.c_str());
if (this->buffer_.length() == MAX_DATA_LENGTH_BYTES && this->buffer_[0] == 'R' &&
this->buffer_.back() == static_cast<char>(ASCII_CR)) {
int millimeters = strtol(this->buffer_.substr(1, MAX_DATA_LENGTH_BYTES - 2).c_str(), nullptr, 10);
float meters = float(millimeters) / 1000.0;
ESP_LOGV(TAG, "Distance from sensor: %d mm, %f m", millimeters, meters);
this->publish_state(meters);
} else {
ESP_LOGW(TAG, "Invalid data read from sensor: %s", this->buffer_.c_str());
}
this->buffer_.clear();
}
}
void HrxlMaxsonarWrComponent::dump_config() {
ESP_LOGCONFIG(TAG, "HRXL MaxSonar WR Sensor:");
LOG_SENSOR(" ", "Distance", this);
// As specified in the sensor's data sheet
this->check_uart_settings(9600, 1, esphome::uart::UART_CONFIG_PARITY_NONE, 8);
}
} // namespace hrxl_maxsonar_wr
} // namespace esphome