Reorganize drivers and utility modules into lib/ subdirectory and update server and upload scripts

2026-06-17 22:22:02 -04:00
parent 2813c11104
commit 75475723fa
16 changed files with 31 additions and 14 deletions
@@ -0,0 +1,85 @@
+import time
+from machine import I2C, Pin
+
+class SHTC3:
+    """Utility class for Sensirion SHTC3 Temperature and Humidity Sensor."""
+    ADDR = 0x70
+    
+    # Commands
+    WAKE = b'\x35\x17'
+    SLEEP = b'\xB0\x98'
+    MEASURE = b'\x78\x66' # High precision, T first, clock stretching disabled
+
+    def __init__(self, i2c=None):
+        if i2c is None:
+            # Default to ESP32-S3-RLCD-4.2 onboard I2C pins
+            self.i2c = I2C(0, sda=Pin(13), scl=Pin(14))
+        else:
+            self.i2c = i2c
+
+    def _crc8(self, data):
+        """Sensirion CRC-8 checksum calculation (polynom 0x31, init 0xFF)."""
+        crc = 0xFF
+        for byte in data:
+            crc ^= byte
+            for _ in range(8):
+                if crc & 0x80:
+                    crc = (crc << 1) ^ 0x31
+                else:
+                    crc <<= 1
+                crc &= 0xFF
+        return crc
+
+    def read_sensor(self):
+        """Wakes up the sensor, reads temp and humidity, validates CRC, and sleeps.
+        
+        Returns:
+            tuple: (temperature_c, relative_humidity_pct) or (None, None) on error.
+        """
+        try:
+            # 1. Wakeup
+            self.i2c.writeto(self.ADDR, self.WAKE)
+            time.sleep_ms(1)
+            
+            # 2. Trigger Measurement
+            self.i2c.writeto(self.ADDR, self.MEASURE)
+            time.sleep_ms(15) # High precision measurement takes up to 12.1ms
+            
+            # 3. Read 6 bytes of data
+            # bytes 0, 1: Temp, byte 2: Temp CRC
+            # bytes 3, 4: Hum,  byte 5: Hum CRC
+            data = self.i2c.readfrom(self.ADDR, 6)
+            
+            # 4. Enter low-power sleep mode
+            self.i2c.writeto(self.ADDR, self.SLEEP)
+            
+            # Verify CRC
+            t_data = data[0:2]
+            t_crc = data[2]
+            h_data = data[3:5]
+            h_crc = data[5]
+            
+            if self._crc8(t_data) != t_crc:
+                print("SHTC3 Temp CRC error")
+                return None, None
+            if self._crc8(h_data) != h_crc:
+                print("SHTC3 Hum CRC error")
+                return None, None
+                
+            raw_t = (data[0] << 8) | data[1]
+            raw_h = (data[3] << 8) | data[4]
+            
+            # Formula from datasheet
+            temp = -45.0 + 175.0 * (raw_t / 65536.0)
+            hum = 100.0 * (raw_h / 65536.0)
+            
+            return round(temp, 2), round(hum, 2)
+            
+        except Exception as e:
+            print(f"Error reading SHTC3 sensor: {e}")
+            # Try to send sleep command anyway to save power
+            try:
+                self.i2c.writeto(self.ADDR, self.SLEEP)
+            except:
+                pass
+            return None, None