Support for configurable threshold

Author: mathieucarbou

README.md

@@ -232,7 +232,7 @@ void setup() {
     continue;
 
   temp.begin(18);
-  
+
   temp.listen([](float temperature, bool changed) {
     JsonDocument doc;
     temp.toJson(doc.to<JsonObject>());
@@ -260,21 +260,21 @@ void setup() {
     continue;
 
   temp.begin(18);
-  
+
   // Temperature readings expire after 30 seconds
   temp.setExpirationDelay(30);
 }
 
 void loop() {
   temp.read();
-  
+
   if (temp.isValid()) {
     float t = temp.getTemperature().value_or(0);
     Serial.printf("Valid temperature: %.2f°C\n", t);
   } else if (temp.isExpired()) {
     Serial.println("Temperature reading expired!");
   }
-  
+
   delay(2000);
 }
 ```

docs/index.md

@@ -232,7 +232,7 @@ void setup() {
     continue;
 
   temp.begin(18);
-  
+
   temp.listen([](float temperature, bool changed) {
     JsonDocument doc;
     temp.toJson(doc.to<JsonObject>());
@@ -260,21 +260,21 @@ void setup() {
     continue;
 
   temp.begin(18);
-  
+
   // Temperature readings expire after 30 seconds
   temp.setExpirationDelay(30);
 }
 
 void loop() {
   temp.read();
-  
+
   if (temp.isValid()) {
     float t = temp.getTemperature().value_or(0);
     Serial.printf("Valid temperature: %.2f°C\n", t);
   } else if (temp.isExpired()) {
     Serial.println("Temperature reading expired!");
   }
-  
+
   delay(2000);
 }
 ```

examples/Threshold/Threshold.ino

@@ -0,0 +1,25 @@
+#include <Arduino.h>
+#include <MycilaDS18.h>
+
+Mycila::DS18 temp;
+
+void setup() {
+  Serial.begin(115200);
+  while (!Serial)
+    continue;
+
+  temp.setThreshold(0.0f); // any temperature change will be reported in callback
+
+  temp.listen([](float temperature, bool changed) {
+    if (changed) {
+      Serial.printf("Temperature changed: %f°C\n", temperature);
+    }
+  });
+
+  temp.begin(18);
+}
+
+void loop() {
+  temp.read();
+  delay(1000);
+}

library.json

@@ -1,6 +1,6 @@
 {
   "name": "MycilaDS18",
-  "version": "5.1.1",
+  "version": "5.2.0",
   "description": "ESP32 / Arduino Library for Dallas / Maxim DS18 sensor using RMT peripheral",
   "homepage": "https://github.com/mathieucarbou/MycilaDS18",
   "repository": {

library.properties

@@ -1,5 +1,5 @@
 name=MycilaDS18
-version=5.1.1
+version=5.2.0
 author=Mathieu Carbou <mathieu.carbou@gmail.com>
 maintainer=Mathieu Carbou <mathieu.carbou@gmail.com>
 sentence=ESP32 / Arduino Library for Dallas / Maxim DS18 sensor using RMT peripheral

platformio.ini

@@ -26,7 +26,8 @@ lib_dir = .
 ; src_dir = examples/Search
 ; src_dir = examples/Json
 ; src_dir = examples/SetAddress
-src_dir = examples/MultipleDS18
+; src_dir = examples/MultipleDS18
+src_dir = examples/Threshold
 
 [env:arduino-3]
 platform = https://github.com/pioarduino/platform-espressif32/releases/download/55.03.34/platform-espressif32.zip

src/MycilaDS18.cpp

@@ -148,14 +148,11 @@ bool Mycila::DS18::read() {
   // read is valid, record the time
   _lastTime = millis();
 
-  // make it on 2 decimals
-  read = round(read * 100.0f) / 100.0f;
-
-  const bool changed = std::abs(read - _temperature) >= MYCILA_DS18_RELEVANT_TEMPERATURE_CHANGE || !isValid();
+  const bool changed = std::abs(read - _temperature) > _threshold || !isValid();
 
   if (changed) {
     _temperature = read;
-    ESP_LOGD(TAG, "%s 0x%llx @ pin %d: %.2f °C", _name, _deviceAddress, _pin, read);
+    ESP_LOGD(TAG, "%s 0x%llx @ pin %d: %f °C", _name, _deviceAddress, _pin, read);
   }
 
   if (_callback)

src/MycilaDS18.h

@@ -5,6 +5,7 @@
 #pragma once
 
 #include <esp_idf_version.h>
+
 #include "./esp32-ds18b20/OneWireESP32.h"
 
 #ifdef MYCILA_JSON_SUPPORT
@@ -15,12 +16,11 @@
 
 #include <mutex>
 #include <optional>
-#include <utility>
 
-#define MYCILA_DS18_VERSION          "5.1.1"
+#define MYCILA_DS18_VERSION          "5.2.0"
 #define MYCILA_DS18_VERSION_MAJOR    5
-#define MYCILA_DS18_VERSION_MINOR    1
-#define MYCILA_DS18_VERSION_REVISION 1
+#define MYCILA_DS18_VERSION_MINOR    2
+#define MYCILA_DS18_VERSION_REVISION 0
 
 // If the temperature is changing from less than 0.3 degrees, we consider it has not changed, to avoid too many updates
 // Example:
@@ -107,6 +107,14 @@ namespace Mycila {
 
       OneWire32* getOneWire() const { return _oneWire; }
 
+      float getThreshold() const { return _threshold; }
+
+      /**
+       * @brief Set the temperature change threshold to consider a change relevant enough to trigger the callback
+       * @param threshold The temperature change threshold in degrees Celsius, default is MYCILA_DS18_RELEVANT_TEMPERATURE_CHANGE
+       */
+      void setThreshold(float threshold) { _threshold = threshold; }
+
 #ifdef MYCILA_JSON_SUPPORT
       void toJson(const JsonObject& root) const;
 #endif
@@ -119,6 +127,7 @@ namespace Mycila {
       bool _enabled = false;
       const char* _name = "Unknown";
       float _temperature = 0;
+      float _threshold = MYCILA_DS18_RELEVANT_TEMPERATURE_CHANGE;
       uint32_t _lastTime = 0;
       uint32_t _expirationDelay = 0;
       DS18ChangeCallback _callback = nullptr;

src/esp32-ds18b20/OneWireESP32.cpp

@@ -263,7 +263,26 @@ void OneWire32::request(uint64_t& addr) {
   }
 }
 
-const uint8_t crc_table[] = {0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65, 157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220, 35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98, 190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255, 70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7, 219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154, 101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36, 248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185, 140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205, 17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80, 175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238, 50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115, 202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139, 87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22, 233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168, 116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53};
+// clang-format off
+const uint8_t crc_table[] = {
+  0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65,
+  157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220,
+  35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98,
+  190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255,
+  70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7,
+  219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154,
+  101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36,
+  248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185,
+  140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205,
+  17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80,
+  175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238,
+  50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115,
+  202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139,
+  87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22,
+  233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168,
+  116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53
+};
+// clang-format on
 
 OneWire32::Result OneWire32::getTemp(uint64_t& addr, float& temp) {
   if (!drv) {

src/esp32-ds18b20/OneWireESP32.h

@@ -36,7 +36,7 @@ class OneWire32 {
     gpio_num_t pin() const { return owpin; }
     bool reset();
     void request();
-    void request(uint64_t &addr);
+    void request(uint64_t& addr);
     Result getTemp(uint64_t& addr, float& temp);
     uint8_t search(uint64_t* addresses, uint8_t total);
     bool read(uint8_t& data, uint8_t len = 8);