Add specific example for M5Stack ENVIII unit

examples/advanced/m5_env.rb

@@ -0,0 +1,41 @@
+#
+# This example combines the SHTX and QMP6988 examples. The M5Stack ENV III unit
+# contains both sensors, accessible over a single I2C connection.
+#
+require 'bundler/setup'
+require 'denko'
+
+board = Denko::Board.new(Denko::Connection::Serial.new)
+bus = Denko::I2C::Bus.new(board: board, pin: :SDA)
+sht = Denko::Sensor::SHT3X.new(bus: bus) # address: 0x44 default
+qmp = Denko::Sensor::QMP6988.new(bus: bus) # address: 0x70 default
+
+# Configure for higher accuracy.
+sht.repeatability = :high
+qmp.temperature_samples = 2
+qmp.pressure_samples = 16
+qmp.iir_coefficient = 2
+
+# Get the shared #print_tph_reading method to print readings neatly.
+require_relative 'neat_tph_readings'
+
+# How many degrees C the two temperature values can differ by before a warning.
+TOLERANCE = 0.50
+
+loop do
+  # Read both sensors.
+  qmp_reading = qmp.read
+  sht_reading = sht.read
+
+  # Warn if large gap between temperature readings.
+  difference = (qmp_reading[:temperature] - sht_reading[:temperature]).abs
+  if (difference > TOLERANCE)
+    puts "WARNING: temperature values differed by more than #{TOLERANCE}\xC2\xB0C (#{difference.round(4)} \xC2\xB0C actual)"
+  end
+
+  # Combine values from both sensors, averaging their temperatures.
+  average_temperature = (qmp_reading[:temperature] + sht_reading[:temperature]) / 2.0
+  print_tph_reading(temperature: average_temperature, humidity: sht_reading[:humidity], pressure: qmp_reading[:pressure])
+
+  sleep 5
+end

examples/sensor/sht3x.rb

@@ -6,7 +6,7 @@
 
 board = Denko::Board.new(Denko::Connection::Serial.new)
 bus = Denko::I2C::Bus.new(board: board, pin: :SDA)
-sensor = Denko::Sensor::SHT3X.new(bus: bus)
+sensor = Denko::Sensor::SHT3X.new(bus: bus) # address: 0x44 default
 
 # Heater control
 sensor.heater_on