Added BME280 telemetry plugin

docs/example_plugins/bme280_telemetry.py

@@ -0,0 +1,67 @@
+# This plugin provides temperature, humidity
+# and pressure data via a BME280 sensor
+# connected over I2C. The plugin requires
+# the "smbus2" and "RPi.bme280" modules to
+# be available on your system. These can be
+# installed with:
+#
+# pip install smbus2 RPi.bme280
+
+import os
+import RNS
+from importlib.util import find_spec
+
+class BME280Plugin(SidebandTelemetryPlugin):
+    plugin_name = "telemetry_bme280"
+
+    I2C_ADDRESS = 0x76
+    I2C_BUS     = 1
+
+    # If your BME280 has an offset from the true
+    # temperature, you can compensate for this
+    # by modifying this parameter.
+    TEMPERATURE_CORRECTION = 0.0
+
+    def start(self):
+        RNS.log("BME280 telemetry plugin starting...")
+
+        if find_spec("smbus2"): import smbus2
+        else: raise OSError(f"No smbus2 module available, cannot start BME280 telemetry plugin")
+        
+        if find_spec("bme280"): import bme280
+        else: raise OSError(f"No bme280 module available, cannot start BME280 telemetry plugin")
+
+        self.sensor_connected = False
+
+        try:
+            self.bme280 = bme280
+            self.address = self.I2C_ADDRESS
+            self.bus = smbus2.SMBus(self.I2C_BUS)
+            self.calibration = self.bme280.load_calibration_params(self.bus, self.address)
+            self.sensor_connected = True
+            self.tc = self.TEMPERATURE_CORRECTION
+        
+        except Exception as e:
+            RNS.log(f"Could not connect to I2C device while starting BME280 telemetry plugin", RNS.LOG_ERROR)
+            RNS.log(f"The contained exception was: {e}", RNS.LOG_ERROR)
+
+        super().start()
+
+    def stop(self):
+        self.bus.close()
+        super().stop()
+
+    def update_telemetry(self, telemeter):
+        if telemeter != None:
+            if self.sensor_connected:
+                try:
+                    sample = self.bme280.sample(self.bus, self.address, self.calibration); ts = telemeter.sensors
+                    telemeter.synthesize("temperature"); ts["temperature"].data = {"c": round(sample.temperature+self.tc,1)}
+                    telemeter.synthesize("humidity");    ts["humidity"].data    = {"percent_relative": round(sample.humidity,1)}
+                    telemeter.synthesize("pressure");    ts["pressure"].data    = {"mbar": round(sample.pressure,1)}
+
+                except Exception as e:
+                    RNS.log("An error occurred while updating BME280 sensor data", RNS.LOG_ERROR)
+                    RNS.log(f"The contained exception was: {e}", RNS.LOG_ERROR)
+
+plugin_class = BME280Plugin