diff --git a/libraries/AnalogUVSensor/.arduino-ci.yml b/libraries/AnalogUVSensor/.arduino-ci.yml
index ff5659b9..e7cb4633 100644
--- a/libraries/AnalogUVSensor/.arduino-ci.yml
+++ b/libraries/AnalogUVSensor/.arduino-ci.yml
@@ -2,6 +2,10 @@ compile:
   # Choosing to run compilation tests on 2 different Arduino platforms
   platforms:
     - uno
-    - leonardo
-    - due
-    - zero
+    # - due
+    # - zero
+    # - leonardo
+    - m4
+    - esp32
+    # - esp8266
+    # - mega2560
\ No newline at end of file
diff --git a/libraries/AnalogUVSensor/AnalogUVSensor.cpp b/libraries/AnalogUVSensor/AnalogUVSensor.cpp
index fc90c311..a84380cc 100644
--- a/libraries/AnalogUVSensor/AnalogUVSensor.cpp
+++ b/libraries/AnalogUVSensor/AnalogUVSensor.cpp
@@ -1,12 +1,14 @@
 //
 //    FILE: AnalogUVSensor.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.0
+// VERSION: 0.1.1
 //    DATE: 2021-09-25
 // PURPOSE: AnalogUVSensor library
 //
 //  HISTORY:
 //  0.1.0  2021-09-25  initial version
+//  0.1.1  2021-10-17  update build-ci, readme.md
+//                     refactor, plotter example
 
 
 #include "AnalogUVSensor.h"
@@ -34,6 +36,7 @@ void AnalogUVSensor::begin(uint8_t analogPin, float volts, uint16_t maxADC)
 float AnalogUVSensor::read(uint8_t times)
 {
   uint32_t sum = 0;
+  if (times == 0) times = 1;
   for (int i = 0; i < times; i++)
   {
     sum += analogRead(_analogPin);
@@ -50,7 +53,8 @@ float AnalogUVSensor::mV2index(uint16_t milliVolt)
   if (milliVolt < 227) return 0.0 + (1.0 * milliVolt - 50.0) / (227.0 - 50.0);
   // linear interpolation between 1..11
   // formula derived with spreadsheet.
-  return 0.0104865310 * milliVolt - 1.289154988;
+  if (milliVolt < 1200) return 0.0104865310 * milliVolt - 1.289154988;
+  return 12;
 }
 
 
diff --git a/libraries/AnalogUVSensor/AnalogUVSensor.h b/libraries/AnalogUVSensor/AnalogUVSensor.h
index 9c038ffa..2ce96472 100644
--- a/libraries/AnalogUVSensor/AnalogUVSensor.h
+++ b/libraries/AnalogUVSensor/AnalogUVSensor.h
@@ -2,7 +2,7 @@
 //
 //    FILE: AnalogUVSensor.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.0
+// VERSION: 0.1.1
 //    DATE: 2021-09-25
 // PURPOSE: AnalogUVSensor library
 //
@@ -12,7 +12,7 @@
 
 #include "Arduino.h"
 
-#define ANALOG_UVSENSOR_LIB_VERSION        (F("0.1.0"))
+#define ANALOG_UVSENSOR_LIB_VERSION        (F("0.1.1"))
 
 
 class AnalogUVSensor
diff --git a/libraries/AnalogUVSensor/README.md b/libraries/AnalogUVSensor/README.md
index 2783e2d8..6ea5cb17 100644
--- a/libraries/AnalogUVSensor/README.md
+++ b/libraries/AnalogUVSensor/README.md
@@ -1,7 +1,16 @@
+
+[![Arduino CI](https://github.com/RobTillaart/AnalogUVSensor/actions/workflows/arduino_test_runner.yml/badge.svg)](https://github.com/RobTillaart/AnalogUVSensor/actions/workflows/arduino_test_runner.yml)
+[![Arduino-lint](https://github.com/RobTillaart/AnalogUVSensor/actions/workflows/arduino-lint.yml/badge.svg)](https://github.com/RobTillaart/AnalogUVSensor/actions/workflows/arduino-lint.yml)
+[![JSON check](https://github.com/RobTillaart/AnalogUVSensor/actions/workflows/jsoncheck.yml/badge.svg)](https://github.com/RobTillaart/AnalogUVSensor/actions/workflows/jsoncheck.yml)
+[![License: MIT](https://img.shields.io/badge/license-MIT-green.svg)](https://github.com/RobTillaart/AnalogUVSensor/blob/master/LICENSE)
+[![GitHub release](https://img.shields.io/github/release/RobTillaart/AnalogUVSensor.svg?maxAge=3600)](https://github.com/RobTillaart/AnalogUVSensor/releases)
+
+
 # AnalogUVSensor
 
 Arduino library for analogue UV sensor
 
+
 ## Description
 
 ![Foo](https://www.tinytronics.nl/shop/image/cache/catalog/products/product-003601/uv-light-sensor-module-200-370nm-80x80w.jpg)
@@ -28,42 +37,55 @@ The sensor has an analogue output that is roughly linear with the UV-index (sunl
 |  1.170> |    11    |
 
 From this table the formula is derived (spreadsheet) which is pretty linear between UV 1 and 11.
+Between 0 and 1 there seems to be a curve / other linear relation.
 
 
 ### Notes
 
-Note: The sensor is not calibrated and the table is indicative for sunlight (assumption!) 
+Note: The sensor is not calibrated and the table is indicative for sunlight (warning assumption!) 
 and therefore not suitable for e.g. medical or industrial usage. 
 
-Note: UV radiation will not go through glass, so inside you will most likely always read zero. 
-This may help to calibrate the zero level of the sensor.
+Note: UV radiation will not go through normal glass, so inside (a house) you will most likely always read zero. 
+This may of course help to calibrate the zero level of the sensor.
 
 Note: depending on the light source used, the table above is incorrect. 
-If one wants to use other values one need to fix this in the **mv2index()** function.
+If one wants to use other values one need to fix the formula in the **mv2index()** function.
+
+Note: the output of the sensor is typically 0 .. 1.1 volt. To increase precision one might configure
+the ADC used to match this voltage range. E.g. Arduino UNO can be set to use an internal 1.1 volt reference.
+See Arduino manual **setAnalogReference()**
+ 
 
 
-### Sensitivity
+### Wavelength sensitivity
 
 The sensor is sensitive for wavelengths from 200 - 370 nm, so mostly in UVB and UVA region and less in the UVC. 
+There is no information about the detailed wavelength sensitivity, so it is not possible to compensate. 
+However one could assume that there is a normal (or other) distribution over the 200 - 370 nm range and create 
+a compensation table based upon the assumed distribution. 
 
-https://en.wikipedia.org/wiki/Ultraviolet
+More about UV see - https://en.wikipedia.org/wiki/Ultraviolet
 
 
 ## Interface
 
 - **AnalogUVSensor()** Constructor.
 - **void begin(uint8_t analogPin, float volts = 5.0, uint16_t maxADC = 1023)** 
-set the parameters of the sensor, analogPin, volts and maxADC to specify the internal ADC. Volts and maxADC have a default so these can be omitted.  
-Note that one needs to reset these parameters if the settings of the internal ADC are 
+set the parameters of the sensor, analogPin, volts and maxADC to specify the internal ADC. 
+Volts and maxADC have a default so these can be omitted if these match.  
+Note: one needs to reset these parameters if the settings of the internal ADC are 
 changed e.g. to INTERNAL_1V1 to change the accuracy.
 - **float read(uint8_t times = 1)** Returns the UV index.  
 Read the analogue sensor one (or more) times to average the reading. 
-This can improve the accuracy of the reading.
+This can improve the accuracy of the reading.  
+If times == 0 it is set to 1.
 - **float mV2index(uint16_t milliVolt)** Returns the UV index.  
-The conversion formula from milliVolt to the UV index used internally by the **read()** function.  
+The conversion formula from milliVolt to the UV index is used internally by the **read()** function.  
 This function can also be called with a voltage measured with an external ADC.  
-- **char index2color(float index)** Converts an index to the first letter of Green, 
-Yellow, Orange, Red or Purple. Can be used as indication on a user interface.  
+THe function will return a value between 0.0 and 12.0. 
+- **char index2color(float index)** Converts an UV index to the first letter of **G**reen, 
+**Y**ellow, **O**range, **R**ed or **P**urple.  
+Can be used as indication on a user interface.  
 This function can also be called with an index from an other UV index sensor.
 
 
@@ -73,9 +95,10 @@ Works only if setPowerPin is called properly.
 
 - **void setPowerPin(uint8_t powerPin, bool invert = false)** 
 Can be used to control the power of the sensor e.g. for low power mode. 
-Optionally one can set the invert flag to **true** to invert the **HIGH LOW** levels e.g. when the analogue sensor is switched through a MOSFET.
-- **void switchOff()** should switch off the power of the sensor. 
-- **void switchOn()** should switch on the power of the sensor.
+Optionally one can set the invert flag to **true** to invert the **HIGH LOW** levels 
+e.g. when the analogue sensor is switched through a MOSFET.
+- **void switchOff()** switch off the power of the sensor. 
+- **void switchOn()** switch on the power of the sensor.
 
 
 ### Future
@@ -85,7 +108,8 @@ Optionally one can set the invert flag to **true** to invert the **HIGH LOW** le
 - investigate response time to stabilize e.g. does it react fast on clouds.
 - investigate with different light sources (UVled, TL, sunlight).
 - investigate time needed to first (stable) measurement.
-- **index2time()** calculate max exposure time? dangerous?
+- **index2time()** calculate max exposure time? dangerous advice?
+- **uint32_t index2RGB(float index)** full colour RGB mapping. 
 
 
 ## Sponsor 
diff --git a/libraries/AnalogUVSensor/examples/analog_uv_sensor/analog_uv_sensor.ino b/libraries/AnalogUVSensor/examples/analog_uv_sensor/analog_uv_sensor.ino
index 72dc75d4..7721b2f6 100644
--- a/libraries/AnalogUVSensor/examples/analog_uv_sensor/analog_uv_sensor.ino
+++ b/libraries/AnalogUVSensor/examples/analog_uv_sensor/analog_uv_sensor.ino
@@ -1,7 +1,6 @@
 //
 //    FILE: UV_sensor.ino
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.0
 // PURPOSE: demo
 //    DATE: 2021-09-21
 
diff --git a/libraries/AnalogUVSensor/examples/uvi_color/uvi_color.ino b/libraries/AnalogUVSensor/examples/uvi_color/uvi_color.ino
index e5e83a40..79f49245 100644
--- a/libraries/AnalogUVSensor/examples/uvi_color/uvi_color.ino
+++ b/libraries/AnalogUVSensor/examples/uvi_color/uvi_color.ino
@@ -1,7 +1,6 @@
 //
 //    FILE: demUV.ino
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.0
 // PURPOSE: demo UV sensor
 //    DATE: 2021-09-25
 
@@ -25,7 +24,7 @@ void setup()
 
 void loop()
 {
-  float uvi = AUV.read();
+  float uvi = AUV.read(3);      // average 3 readings
   Serial.print("UVI: ");
   Serial.print(uvi, 1);
   Serial.print("\t");
diff --git a/libraries/AnalogUVSensor/examples/uvi_demo/uvi_demo.ino b/libraries/AnalogUVSensor/examples/uvi_demo/uvi_demo.ino
index 4a77797b..dfaa3f5a 100644
--- a/libraries/AnalogUVSensor/examples/uvi_demo/uvi_demo.ino
+++ b/libraries/AnalogUVSensor/examples/uvi_demo/uvi_demo.ino
@@ -1,7 +1,6 @@
 //
 //    FILE: uvi_demo.ino
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.0
 // PURPOSE: demo UV sensor
 //    DATE: 2021-09-25
 
@@ -24,7 +23,7 @@ void setup()
 
 void loop()
 {
-  float uvi = AUV.read();
+  float uvi = AUV.read(5);      // average 5 readings
   Serial.print("UVI: ");
   Serial.println(uvi, 1);
   delay(1000);
diff --git a/libraries/AnalogUVSensor/examples/uvi_demo_low_power/uvi_demo_low_power.ino b/libraries/AnalogUVSensor/examples/uvi_demo_low_power/uvi_demo_low_power.ino
index 25308815..e60c6da2 100644
--- a/libraries/AnalogUVSensor/examples/uvi_demo_low_power/uvi_demo_low_power.ino
+++ b/libraries/AnalogUVSensor/examples/uvi_demo_low_power/uvi_demo_low_power.ino
@@ -1,7 +1,6 @@
 //
 //    FILE: uvi_demo_low_power.ino
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.0
 // PURPOSE: demo UV sensor
 //    DATE: 2021-09-25
 
@@ -21,7 +20,7 @@ void setup()
 
   AUV.begin(A0, 5.0, 1023);
   
-  AUV.setPowerPin(4);
+  AUV.setPowerPin(4);           // connect power of sensor to pin 4
   AUV.switchOff();
 }
 
@@ -29,7 +28,7 @@ void setup()
 void loop()
 {
   AUV.switchOn();
-  float uvi = AUV.read();
+  float uvi = AUV.read();       // default is 1 read
   AUV.switchOff();
 
   Serial.print("UVI: ");
diff --git a/libraries/AnalogUVSensor/examples/uvi_plotter/uvi_plotter.ino b/libraries/AnalogUVSensor/examples/uvi_plotter/uvi_plotter.ino
new file mode 100644
index 00000000..97b755f6
--- /dev/null
+++ b/libraries/AnalogUVSensor/examples/uvi_plotter/uvi_plotter.ino
@@ -0,0 +1,47 @@
+//
+//    FILE: uvi_plotter.ino
+//  AUTHOR: Rob Tillaart
+// PURPOSE: demo UV sensor
+//    DATE: 2021-10-17
+
+// Use the Arduino IDE -> Tools -> Serial plotter 
+// to get a graph.
+
+#include "AnalogUVSensor.h"
+
+AnalogUVSensor AUV;
+float lastRead = 0;
+
+void setup()
+{
+  Serial.begin(115200);
+  //  Serial.println(__FILE__);
+  //  Serial.print("ANALOG_UVSENSOR_LIB_VERSION: ");
+  //  Serial.println(ANALOG_UVSENSOR_LIB_VERSION);
+
+  AUV.begin(A0, 5.0, 1023);
+  lastRead = AUV.read(5);      // average 5 readings
+
+  // print the header for the plotter.
+  Serial.println("UVI \tLAST \tDELTA");
+}
+
+
+void loop()
+{
+  float uvi = AUV.read(5);      // average 5 readings
+  float delta = uvi - lastRead;
+
+  Serial.print(uvi, 1);
+  Serial.print('\t');
+  Serial.print(lastRead, 1);
+  Serial.print('\t');
+  Serial.print(delta, 1);
+  Serial.print('\n');
+
+  lastRead = uvi;
+  delay(1000);
+}
+
+
+// -- END OF FILE --
diff --git a/libraries/AnalogUVSensor/examples/uvi_test/uvi_test.ino b/libraries/AnalogUVSensor/examples/uvi_test/uvi_test.ino
index b652b835..d3e7e4ba 100644
--- a/libraries/AnalogUVSensor/examples/uvi_test/uvi_test.ino
+++ b/libraries/AnalogUVSensor/examples/uvi_test/uvi_test.ino
@@ -1,7 +1,6 @@
 //
 //    FILE: uvi_test.ino
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.0
 // PURPOSE: demo UV sensor
 //    DATE: 2021-09-25
 
diff --git a/libraries/AnalogUVSensor/library.json b/libraries/AnalogUVSensor/library.json
index 2e0eb54f..38c24c41 100644
--- a/libraries/AnalogUVSensor/library.json
+++ b/libraries/AnalogUVSensor/library.json
@@ -15,7 +15,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/AnalogUVSensor.git"
   },
-  "version": "0.1.0",
+  "version": "0.1.1",
   "license": "MIT",
   "frameworks": "arduino",
   "platforms": "*"
diff --git a/libraries/AnalogUVSensor/library.properties b/libraries/AnalogUVSensor/library.properties
index a06a4c3b..c92d7503 100644
--- a/libraries/AnalogUVSensor/library.properties
+++ b/libraries/AnalogUVSensor/library.properties
@@ -1,5 +1,5 @@
 name=AnalogUVSensor
-version=0.1.0
+version=0.1.1
 author=Rob Tillaart <rob.tillaart@gmail.com>
 maintainer=Rob Tillaart <rob.tillaart@gmail.com>
 sentence=AnalogUVSensor library for Arduino.