v5.12.0b - Add support for sensor SHTC3

5.12.0b
 * Add support for sensor SHTC3 (arendst#1967)

Author: arendst

sonoff/_releasenotes.ino

@@ -13,6 +13,7 @@
  * Change Sonoff SC JSON format (#1939)
  * Fix compile error when define HOME_ASSISTANT_DISCOVERY_ENABLE is not set (#1937)
  * Add optional TSL2561 driver using library Joba_Tsl2561 to be enabled in user_config.h with define USE_TSL2561_JOBA (#1951)
+ * Add support for sensor SHTC3 (#1967)
  *
  * 5.12.0a
  * Change platformio option sonoff-ds18x20 to sonoff-xxl enabling ds18x20 and all other sensors in one image

sonoff/user_config.h

@@ -183,7 +183,7 @@
 #define USE_I2C                                  // I2C using library wire (+10k code, 0k2 mem, 124 iram)
 #ifdef USE_I2C
   #define USE_SHT                                // Add I2C emulating code for SHT1X sensor (+1k4 code)
-  #define USE_SHT3X                              // Add I2C code for SHT3x sensor (+0k6 code)
+  #define USE_SHT3X                              // Add I2C code for SHT3x or SHTC3 sensor (+0k7 code)
   #define USE_HTU                                // Add I2C code for HTU21/SI7013/SI7020/SI7021 sensor (+1k5 code)
   #define USE_BMP                                // Add I2C code for BMP085/BMP180/BMP280/BME280 sensor (+4k code)
 //    #define USE_BME680                           // Add additional support for BME680 sensor using Adafruit Sensor and BME680 libraries (+6k code)

sonoff/xsns_14_sht3x.ino

@@ -20,17 +20,21 @@
 #ifdef USE_I2C
 #ifdef USE_SHT3X
 /*********************************************************************************************\
- * SHT3X - Temperature and Humidy
+ * SHT3X and SHTC3 - Temperature and Humidy
  *
- * I2C Address: 0x44 or 0x45
+ * I2C Address: 0x44, 0x45 or 0x70 (SHTC3)
 \*********************************************************************************************/
 
 #define SHT3X_ADDR_GND      0x44       // address pin low (GND)
 #define SHT3X_ADDR_VDD      0x45       // address pin high (VDD)
+#define SHTC3_ADDR          0x70       // address for shtc3 sensor
+
+const char kShtTypes[] PROGMEM = "SHT3X|SHT3X|SHTC3";
 
 uint8_t sht3x_type = 0;
 uint8_t sht3x_address;
-uint8_t sht3x_addresses[] = { SHT3X_ADDR_GND, SHT3X_ADDR_VDD };
+uint8_t sht3x_addresses[] = { SHT3X_ADDR_GND, SHT3X_ADDR_VDD, SHTC3_ADDR };
+char sht3x_types[6];
 
 bool Sht3xRead(float &t, float &h)
 {
@@ -40,8 +44,17 @@ bool Sht3xRead(float &t, float &h)
   h = NAN;
 
   Wire.beginTransmission(sht3x_address);
-  Wire.write(0x2C);                    // Enable clock stretching
-  Wire.write(0x06);                    // High repeatability
+  if (SHTC3_ADDR == sht3x_address) {
+    Wire.write(0x35);                  // Wake from
+    Wire.write(0x17);                  // sleep
+    Wire.endTransmission();
+    Wire.beginTransmission(sht3x_address);
+    Wire.write(0x78);                  // Dissable clock stretching ( I don't think that wire library support clock stretching )
+    Wire.write(0x66);                  // High resolution
+  } else {
+    Wire.write(0x2C);                  // Enable clock stretching
+    Wire.write(0x06);                  // High repeatability
+  }
   if (Wire.endTransmission() != 0) {   // Stop I2C transmission
     return false;
   }
@@ -69,7 +82,8 @@ void Sht3xDetect()
   for (byte i = 0; i < sizeof(sht3x_addresses); i++) {
     sht3x_address = sht3x_addresses[i];
     if (Sht3xRead(t, h)) {
-      snprintf_P(log_data, sizeof(log_data), S_LOG_I2C_FOUND_AT, "SHT3X", sht3x_address);
+      GetTextIndexed(sht3x_types, sizeof(sht3x_types), i, kShtTypes);
+      snprintf_P(log_data, sizeof(log_data), S_LOG_I2C_FOUND_AT, sht3x_types, htu_address);
       AddLog(LOG_LEVEL_DEBUG);
       return;
     }
@@ -89,14 +103,14 @@ void Sht3xShow(boolean json)
       dtostrfd(h, Settings.flag2.humidity_resolution, humidity);
 
       if (json) {
-        snprintf_P(mqtt_data, sizeof(mqtt_data), JSON_SNS_TEMPHUM, mqtt_data, "SHT3X", temperature, humidity);
+        snprintf_P(mqtt_data, sizeof(mqtt_data), JSON_SNS_TEMPHUM, mqtt_data, sht3x_types, temperature, humidity);
 #ifdef USE_DOMOTICZ
         DomoticzTempHumSensor(temperature, humidity);
 #endif  // USE_DOMOTICZ
 #ifdef USE_WEBSERVER
       } else {
-        snprintf_P(mqtt_data, sizeof(mqtt_data), HTTP_SNS_TEMP, mqtt_data, "SHT3X", temperature, TempUnit());
-        snprintf_P(mqtt_data, sizeof(mqtt_data), HTTP_SNS_HUM, mqtt_data, "SHT3X", humidity);
+        snprintf_P(mqtt_data, sizeof(mqtt_data), HTTP_SNS_TEMP, mqtt_data, sht3x_types, temperature, TempUnit());
+        snprintf_P(mqtt_data, sizeof(mqtt_data), HTTP_SNS_HUM, mqtt_data, sht3x_types, humidity);
 #endif  // USE_WEBSERVER
       }
     }