Library for single or multiple temperature sensor(s) DS18B20 with alarm support on ESP32

Usage

In both examples (single and multiple) sensors data pin is connected to GPIO15 on ESP32.

You may disable or enable logging in the library by setting LOGGING_ENABLED in the top of ds18b20.c file:

#define LOGGING_ENABLED     0 // logging disabled
#define LOGGING_ENABLED     1 // logging enabled

Single DS18B20:

if (ds18b20_init(15) == true) {
  ESP_LOGI(TAG, "Initialization completed.");
}
else {
  ESP_LOGI(TAG, "Initialization failed!");
}

float temperature;
if (ds18b20_get_temperature(&temperature, NULL) == true) {
  ESP_LOGI(TAG, "Temperature: %0.1f", temperature);
}
else {
  ESP_LOGI(TAG, "Error reading temperature!");
}

Optional to set sensor resolution to 11 bit:

if (ds18b20_set_thermometer_resolution(RES_11_BIT, NULL) == true) {
  ESP_LOGI(TAG, "Successfully set temperature resolution to 11 bit.");
}
else {
  ESP_LOGI(TAG, "Failed to set temperature resolution to 11 bit!");
}	

Optional to set low alarm temperature to -6°C and high alarm temerature to 30°C:

if (ds18b20_set_alarm_temperature(30, -6, NULL) == true) {
  ESP_LOGI(TAG, "Successfully set alarm temperatures.");
}
else {
  ESP_LOGI(TAG, "Failed to set alarm temperatures!");
}

Optional to get a low alarm temperature for a sensor:

int8_t temperatureLow;
if (ds18b20_get_alarm_temperature_low(&temperatureLow, NULL) == true) {
  ESP_LOGI(TAG, "Low alarm temperature: %d", temperatureLow);
}
else {
  ESP_LOGI(TAG, "Failed to get a low alarm temperature!");
}

Multiple DS18B20:

// Suppose we have 4 sensors

if (ds18b20_init(15) == true) {
  ESP_LOGI(TAG, "Initialization completed.");
}
else {
  ESP_LOGI(TAG, "Initialization failed!");
}

uint8_t address[4][8] = {0};
uint8_t numOfDevices = 0;

while (ds18b20_search_ROM(address[numOfDevices]) == true) {
  numOfDevices++;
  ESP_LOGI(TAG, "Found address number %d.", numOfDevices);
}

for (uint8_t i=0; i<numOfDevices; i++)
{
  float temperature;
  if (ds18b20_get_temperature(&temperature, address[i]) == true) {
    ESP_LOGI(TAG, "Temperature of %d. sensor: %0.1f", i, temperature);
  }
  else {
    ESP_LOGI(TAG, "Error reading temperature of sensor %d!", i);
  }
}

Optional to set sensor resolution to 9 bit:

if (ds18b20_set_thermometer_resolution(RES_9_BIT, address) == true) {
  ESP_LOGI(TAG, "Successfully set temperature resolution to 9 bit.");
}
else {
  ESP_LOGI(TAG, "Failed to set temperature resolution to 9 bit!");
}	

Optional to set high alarm temperature to 28°C:

if (ds18b20_set_alarm_temperature_high(28, address) == true) {
  ESP_LOGI(TAG, "Successfully set alarm temperatures.");
}
else {
  ESP_LOGI(TAG, "Failed to set alarm temperatures!");
}

Optional to check if any sensor has triggered a temperature alarm:

uint8_t alarmAddress[8] = {0};
while (ds18b20_alarm_search(alarmAddress) == true) {
  ESP_LOGI(TAG, "ALARM for address: %x%x%x%x%x%x%x%x", alarmAddress[0], alarmAddress[1], alarmAddress[2], alarmAddress[3], alarmAddress[4], alarmAddress[5], alarmAddress[6], alarmAddress[7]);
}