small changes and many new sensors

ext/sens/SHT3x.h

@@ -0,0 +1,93 @@
+ 
+#pragma once
+
+/**
+ * humidity and temperature sensor
+ * https://www.mouser.com/datasheet/2/682/Sensirion_Humidity_Sensors_SHT3x_Datasheet_digital-971521.pdf
+ * 
+ * sensor seems to be really good! and very easy to use!
+ * 
+ */
+template <typename I2C> class SHT3x {
+	
+private:
+
+	I2C& i2c;
+	static constexpr const uint8_t ADDR = 0x44;
+	static constexpr const char* NAME = "SHT3x";
+	
+
+public:
+
+	SHT3x(I2C& i2c) : i2c(i2c) {
+		
+	}
+			
+	/** is the device present on the bus? */
+	bool isPresent() {
+		return i2c.query(ADDR);
+	}
+			
+	struct Result {
+		float temp;
+		float humi;
+	};
+			
+	/** trigger a single measurement */	
+	Result singleMeasure() {
+		
+		uint16_t cmd = 0x2400;	// high quality, no clock stretching
+		sendCommand(cmd);
+		vTaskDelay(100 / portTICK_PERIOD_MS);
+		
+		return readResult();
+		
+	}
+	
+	void startPeriodicMeasure() {
+		uint16_t cmd = 0x2130;	// high quality, 1 measurement per second
+		sendCommand(cmd);
+	}
+	
+	Result getLastResult() {
+		return readResult();
+	}
+		
+private:
+
+	Result readResult() {
+		
+		uint8_t tmp[6];
+		i2c.readRaw(ADDR, 6, (uint8_t*)&tmp);
+		
+		Result res;
+		res.temp = -45 + 175 * 	((tmp[0]<<8) | (tmp[1]<<0)) / float((1<<16)-1);
+		res.humi = 100 * 		((tmp[3]<<8) | (tmp[4]<<0)) / float((1<<16)-1);
+		return res;
+		
+	}
+
+	void sendCommand(uint16_t cmd) {
+		uint8_t tmp[2];
+		tmp[0] = cmd >> 8;
+		tmp[1] = cmd >> 0;
+		i2c.writeRaw(ADDR, 2, tmp);
+	}
+	
+	static uint8_t calcCRC(const uint8_t* data, uint8_t len) {
+		uint8_t crc = 0xff;
+		for (uint8_t i = 0; i < len; i++) {
+			crc ^= data[i];
+			for (uint8_t j = 0; j < 8; j++) {
+				if ((crc & 0x80) != 0) {
+					crc = (uint8_t)((crc << 1) ^ 0x31);
+				} else {
+					crc <<= 1;
+				}
+			}
+		}
+		return crc;
+	}
+
+	
+};