Move example from README to its own file

Nove the multiple/two sensors example from the readme to its own file.
Add an additional note on why autodetection doesn't work and what
sensor combination is expected to work.

Author: abrauchli

README.md

@@ -36,93 +36,12 @@ necessary:
 from the sensor, but return the values read last. To read a new sample, make
 sure to call `readSample()`
 
-### Sample code
-```c++
-#include <Wire.h>
+## Example projects
 
-#include <SHTSensor.h>
+See example project
+[sht-autodetect](examples/sht-autodetect/sht-autodetect.ino)
 
-SHTSensor sht;
+### Usage with multiple SHT31 sensors
 
-void setup() {
-  // put your setup code here, to run once:
-
-  Wire.begin();
-  Serial.begin(9600);
-  sht.init();
-}
-
-void loop() {
-  // put your main code here, to run repeatedly:
-
-  sht.readSample();
-  Serial.print("SHT:\n");
-  Serial.print("  RH: ");
-  Serial.print(sht.getHumidity(), 2);
-  Serial.print("\n");
-  Serial.print("  T:  ");
-  Serial.print(sht.getTemperature(), 2);
-  Serial.print("\n");
-
-  delay(1000);
-}
-```
-
-### Usage with two SHT31 sensors
-
-```c++
-#include <Wire.h>
-#include "SHTSensor.h"
-
-// Sensor with normal i2c address
-// Sensor 1 with address pin pulled to GND
-SHTSensor sht1(SHTSensor::SHT3X);
-
-// Sensor with alternative i2c address
-// Sensor 2 with address pin pulled to Vdd
-SHTSensor sht2(SHTSensor::SHT3X_ALT);
-
-void setup() {
-  // put your setup code here, to run once:
-  Wire.begin();
-  Serial.begin(9600);
-  delay(1000); // let serial console settle
-
-  // init on a specific sensor type (i.e. without auto detecting), 
-  // does not check if the sensor is responding and will thus always succeed.
-
-  // initialize sensor with normal i2c-address
-  sht1.init();
-
-  // initialize sensor with alternative i2c-address
-  sht2.init();
-}
-void loop() {
-  // put your main code here, to run repeatedly:
-  // read from first sensor
-  if (sht1.readSample()) {
-    Serial.print("SHT1 :\n");
-    Serial.print("  RH: ");
-    Serial.print(sht1.getHumidity(), 2);
-    Serial.print("\n");
-    Serial.print("  T:  ");
-    Serial.print(sht1.getTemperature(), 2);
-    Serial.print("\n");
-  } else {
-    Serial.print("Sensor 1: Error in readSample()\n");
-  }
-  // read from second sensor
-  if (sht2.readSample()) {
-    Serial.print("SHT2:\n");
-    Serial.print("  RH: ");
-    Serial.print(sht2.getHumidity(), 2);
-    Serial.print("\n");
-    Serial.print("  T:  ");
-    Serial.print(sht2.getTemperature(), 2);
-    Serial.print("\n");
-  } else {
-    Serial.print("Sensor 2: Error in readSample()\n");
-  }
-  delay(1000);
-}
-```
+See example project
+[multiple-sht-sensors](examples/multiple-sht-sensors/multiple-sht-sensors.ino)

examples/multiple-sht-sensors/multiple-sht-sensors.ino

@@ -0,0 +1,62 @@
+#include <Wire.h>
+#include "SHTSensor.h"
+
+// Note that all i2c devices sharing one bus must have distinct addresses. Thus
+// this example only works with sensors that have distinct i2c addresses (e.g.
+// SHT3x and SHT3x_alt, or SHT3x and SHTC3).
+// Make sure not to use auto-detection as it will only pick up one sensor.
+
+// Sensor with normal i2c address
+// Sensor 1 with address pin pulled to GND
+SHTSensor sht1(SHTSensor::SHT3X);
+
+// Sensor with alternative i2c address
+// Sensor 2 with address pin pulled to Vdd
+SHTSensor sht2(SHTSensor::SHT3X_ALT);
+
+void setup() {
+  // put your setup code here, to run once:
+  Wire.begin();
+  Serial.begin(9600);
+  delay(1000); // let serial console settle
+
+  // init on a specific sensor type (i.e. without auto detecting),
+  // does not check if the sensor is responding and will thus always succeed.
+
+  // initialize sensor with normal i2c-address
+  sht1.init();
+
+  // initialize sensor with alternative i2c-address
+  sht2.init();
+}
+
+void loop() {
+  // put your main code here, to run repeatedly:
+  // read from first sensor
+  if (sht1.readSample()) {
+    Serial.print("SHT1 :\n");
+    Serial.print("  RH: ");
+    Serial.print(sht1.getHumidity(), 2);
+    Serial.print("\n");
+    Serial.print("  T:  ");
+    Serial.print(sht1.getTemperature(), 2);
+    Serial.print("\n");
+  } else {
+    Serial.print("Sensor 1: Error in readSample()\n");
+  }
+
+  // read from second sensor
+  if (sht2.readSample()) {
+    Serial.print("SHT2:\n");
+    Serial.print("  RH: ");
+    Serial.print(sht2.getHumidity(), 2);
+    Serial.print("\n");
+    Serial.print("  T:  ");
+    Serial.print(sht2.getTemperature(), 2);
+    Serial.print("\n");
+  } else {
+    Serial.print("Sensor 2: Error in readSample()\n");
+  }
+
+  delay(1000);
+}