diff --git a/libraries/LTR390_DFR/.arduino-ci.yml b/libraries/LTR390_DFR/.arduino-ci.yml
new file mode 100644
index 00000000..d9b3a2aa
--- /dev/null
+++ b/libraries/LTR390_DFR/.arduino-ci.yml
@@ -0,0 +1,30 @@
+platforms:
+  rpipico:
+    board: rp2040:rp2040:rpipico
+    package: rp2040:rp2040
+    gcc:
+      features:
+      defines:
+        - ARDUINO_ARCH_RP2040
+      warnings:
+      flags:
+
+packages:
+  rp2040:rp2040:
+    url: https://github.com/earlephilhower/arduino-pico/releases/download/global/package_rp2040_index.json
+
+compile:
+  # Choosing to run compilation tests on 2 different Arduino platforms
+  platforms:
+    - uno
+    # - due
+    # - zero
+    # - leonardo
+    - m4
+    - esp32
+    - esp8266
+    # - mega2560
+    - rpipico
+
+  libraries:
+    - "printHelpers"
diff --git a/libraries/LTR390_DFR/.github/FUNDING.yml b/libraries/LTR390_DFR/.github/FUNDING.yml
new file mode 100644
index 00000000..554358c3
--- /dev/null
+++ b/libraries/LTR390_DFR/.github/FUNDING.yml
@@ -0,0 +1,4 @@
+# These are supported funding model platforms
+
+github: RobTillaart
+custom: "https://www.paypal.me/robtillaart"
diff --git a/libraries/LTR390_DFR/.github/workflows/arduino-lint.yml b/libraries/LTR390_DFR/.github/workflows/arduino-lint.yml
new file mode 100644
index 00000000..7f8f4ef4
--- /dev/null
+++ b/libraries/LTR390_DFR/.github/workflows/arduino-lint.yml
@@ -0,0 +1,13 @@
+name: Arduino-lint
+
+on: [push, pull_request]
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - uses: actions/checkout@v4
+      - uses: arduino/arduino-lint-action@v1
+        with:
+          library-manager: update
+          compliance: strict
\ No newline at end of file
diff --git a/libraries/LTR390_DFR/.github/workflows/arduino_test_runner.yml b/libraries/LTR390_DFR/.github/workflows/arduino_test_runner.yml
new file mode 100644
index 00000000..dbd0ce79
--- /dev/null
+++ b/libraries/LTR390_DFR/.github/workflows/arduino_test_runner.yml
@@ -0,0 +1,17 @@
+name: Arduino CI
+
+on: [push, pull_request]
+
+jobs:
+  runTest:
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 2.6
+      - run: |
+          gem install arduino_ci
+          arduino_ci.rb
diff --git a/libraries/LTR390_DFR/.github/workflows/jsoncheck.yml b/libraries/LTR390_DFR/.github/workflows/jsoncheck.yml
new file mode 100644
index 00000000..1cbb5e2c
--- /dev/null
+++ b/libraries/LTR390_DFR/.github/workflows/jsoncheck.yml
@@ -0,0 +1,18 @@
+name: JSON check
+
+on:
+  push:
+    paths:
+      - '**.json'
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - uses: actions/checkout@v4
+      - name: json-syntax-check
+        uses: limitusus/json-syntax-check@v2
+        with:
+          pattern: "\\.json$"
\ No newline at end of file
diff --git a/libraries/LTR390_DFR/CHANGELOG.md b/libraries/LTR390_DFR/CHANGELOG.md
new file mode 100644
index 00000000..1b8a0066
--- /dev/null
+++ b/libraries/LTR390_DFR/CHANGELOG.md
@@ -0,0 +1,13 @@
+# Change Log LTR390_DFR
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](http://keepachangelog.com/)
+and this project adheres to [Semantic Versioning](http://semver.org/).
+
+
+## [0.1.0] - 2024-04-29
+- initial version
+
+
+
diff --git a/libraries/LTR390_DFR/LICENSE b/libraries/LTR390_DFR/LICENSE
new file mode 100644
index 00000000..37fe70e5
--- /dev/null
+++ b/libraries/LTR390_DFR/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024-2024 Rob Tillaart
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/libraries/LTR390_DFR/LTR390_DFR.h b/libraries/LTR390_DFR/LTR390_DFR.h
new file mode 100644
index 00000000..ece4ee5d
--- /dev/null
+++ b/libraries/LTR390_DFR/LTR390_DFR.h
@@ -0,0 +1,343 @@
+#pragma once
+//
+//    FILE: LTR390_DFR.h
+//  AUTHOR: Rob Tillaart
+//    DATE: 2024-04-29
+// VERSION: 0.1.0
+// PURPOSE: Arduino library for the I2C LTR390 UV sensor (DF Robotics edition).
+//     URL: https://github.com/RobTillaart/LTR390_DFR
+
+
+#include "Arduino.h"
+#include "Wire.h"
+
+
+#define LTR390_DFR_LIB_VERSION         (F("0.1.0"))
+
+//  LTR390 ERROR CODES
+//  TODO
+
+
+//  DF_ROBOTICS LTR390 REGISTERS (16 bits)
+#define LTR390_PID                      0x00
+#define LTR390_ADDRESS                  0x02
+#define LTR390_FIRMWARE                 0x05
+#define LTR390_PART_ID                  0x06
+
+#define LTR390_ALS_DATA_0               0x07
+#define LTR390_ALS_DATA_1               0x08
+#define LTR390_UVS_DATA_0               0x09
+#define LTR390_UVS_DATA_1               0x0A
+
+#define LTR390_GAIN                     0x0B
+#define LTR390_INT_CONFIG               0x0C
+
+#define LTR390_ALS_UVS_THRES_UP_0       0x0D
+#define LTR390_ALS_UVS_THRES_UP_1       0x0E
+#define LTR390_ALS_UVS_THRES_LOW_0      0x0F
+#define LTR390_ALS_UVS_THRES_LOW_1      0x10
+#define LTR390_ALS_UVS_THRES_VAR_DATA   0x11
+
+#define LTR390_ALS_UVS_MEAS_RATE        0x12
+#define LTR390_MAIN_CTRL                0x13
+
+
+class LTR390_DFR
+{
+public:
+  LTR390_DFR(TwoWire *wire = &Wire)
+  {
+    _address = 0x1C;  //  Fixed 0x1C = 28 = DF_ROBOTICS
+    _wire = wire;
+    _gain = 3.0;  //  default
+    _time = 0.1;  //  default 18 bit, 100 ms.
+    _UVsensitivity = 1.0;
+  }
+
+  bool begin()
+  {
+    return isConnected();
+  }
+
+  bool isConnected()
+  {
+    _wire->beginTransmission(_address);
+    return (_wire->endTransmission() == 0);
+  }
+
+  uint8_t getAddress()
+  {
+    return _address;
+  }
+
+
+  //////////////////////////////////////////////
+  //
+  //  MAIN CONTROL
+  //
+  void setALSMode()
+  {
+    writeRegister(LTR390_MAIN_CTRL, 0x02);
+  }
+
+  void setUVSMode()
+  {
+    writeRegister(LTR390_MAIN_CTRL, 0x0A);
+  }
+
+  uint8_t reset()
+  {
+    writeRegister(LTR390_MAIN_CTRL, 0x10);
+    delay(100);
+    return readRegister(LTR390_MAIN_CTRL);
+  }
+
+
+  //////////////////////////////////////////////
+  //
+  //  PART_ID
+  //
+  uint8_t getPartID()
+  {
+    uint8_t reg = readRegister(LTR390_PART_ID);
+    return reg >> 4;
+  }
+
+  uint8_t getRevisionID()
+  {
+    uint8_t reg = readRegister(LTR390_PART_ID);
+    return reg & 0x0F;
+  }
+
+
+  //////////////////////////////////////////////
+  //
+  //  GET DATA
+  //
+  uint32_t getALSData()
+  {
+    return readRegister(8) * 65536UL + readRegister(7);
+  }
+
+  //  page 22 datasheet
+  float getLux(float wfac = 1)
+  {
+    float lux = 0.6 * getALSData() /( _gain * _time);
+    if (wfac > 1) lux *= wfac;
+    return lux;
+  }
+
+  uint32_t getUVSData()
+  {
+    return readRegister(10) * 65536UL + readRegister(9);
+  }
+
+  //  page 22 datasheet
+  float getUVI(float wfac = 1)
+  {
+    float uvi = getUVSData() / _UVsensitivity;
+    if (wfac > 1) uvi *= wfac;
+    return uvi;
+  }
+
+
+  //////////////////////////////////////////////
+  //
+  //  MEASUREMENT CONFIGURATION
+  //
+  //  experimental...
+  //
+  //  TODO does not work as expected yet
+  //
+  void setGain(uint8_t gain)  //  0..4
+  {
+    uint16_t value = gain;
+    if (value > 4) value = 4;
+    writeRegister(LTR390_GAIN, value);
+    _gain = 1;
+    if (value == 1) _gain = 3;
+    if (value == 2) _gain = 6;
+    if (value == 3) _gain = 9;
+    if (value == 4) _gain = 18;
+  }
+
+  uint8_t getGain()
+  {
+    uint16_t reg = readRegister(LTR390_GAIN);
+    return reg & 0x07;
+  }
+
+  //  resolution = 0..5  See datasheet P14.
+  //        time = 0..7  See datasheet P14.
+  void setMeasurement(uint8_t resolution, uint8_t time)
+  {
+    uint16_t value = (resolution << 4) | time;
+    writeRegister(LTR390_ALS_UVS_MEAS_RATE, value);
+    _time = 2.000;
+    if (time == 0) _time = 0.025;
+    if (time == 1) _time = 0.050;
+    if (time == 2) _time = 0.100;
+    if (time == 3) _time = 0.200;
+    if (time == 4) _time = 0.500;
+    if (time == 5) _time = 1.000;
+  }
+
+  uint8_t getResolution()
+  {
+    uint16_t reg = readRegister(LTR390_ALS_UVS_MEAS_RATE);
+    return (reg >> 4) & 0x07;
+  }
+
+  uint8_t getTime()
+  {
+    uint16_t reg = readRegister(LTR390_ALS_UVS_MEAS_RATE);
+    return reg & 0x07;
+  }
+
+
+/*
+  //////////////////////////////////////////////
+  //
+  //  MAIN STATUS
+  //  TODO elaborate - need split? or masks?
+  //
+  uint8_t getStatus()
+  {
+    uint8_t reg = readRegister(LTR390_MAIN_STATUS);
+    return reg & 0x38;
+  }
+*/
+
+
+
+/*
+  //////////////////////////////////////////////
+  //
+  //  INTERRUPT
+  //
+  int setInterruptConfig(uint8_t value)
+  {
+    return writeRegister(LTR390_INT_CFG, value);
+  }
+
+  uint8_t getInterruptConfig()
+  {
+    return readRegister(LTR390_INT_CFG);
+  }
+
+  int setInterruptPersist(uint8_t value)
+  {
+    return writeRegister(LTR390_INT_PST, value);
+  }
+
+  uint8_t getInterruptPersist()
+  {
+    return readRegister(LTR390_INT_PST);
+  }
+*/
+
+
+/*
+  //////////////////////////////////////////////
+  //
+  //  THRESHOLD
+  //
+  void setHighThreshold(uint32_t value)
+  {
+    writeRegister(LTR390_ALS_UVS_THRES_UP_0, value & 0xFF);
+    value >>= 8;
+    writeRegister(LTR390_ALS_UVS_THRES_UP_1, value & 0xFF);
+    value >>= 8;
+    writeRegister(LTR390_ALS_UVS_THRES_UP_2, value & 0x0F);
+  }
+
+  uint32_t getHighThreshold()
+  {
+    uint32_t value = readRegister(LTR390_ALS_UVS_THRES_UP_2) & 0x0F;
+    value <<= 8;
+    value += readRegister(LTR390_ALS_UVS_THRES_UP_1);
+    value <<= 8;
+    value += readRegister(LTR390_ALS_UVS_THRES_UP_0);
+    return value;
+  }
+
+  void setLowThreshold(uint32_t value)
+  {
+    writeRegister(LTR390_ALS_UVS_THRES_LOW_0, value & 0xFF);
+    value >>= 8;
+    writeRegister(LTR390_ALS_UVS_THRES_LOW_1, value & 0xFF);
+    value >>= 8;
+    writeRegister(LTR390_ALS_UVS_THRES_LOW_2, value & 0x0F);
+  }
+
+  uint32_t getLowThreshold()
+  {
+    uint32_t value = readRegister(LTR390_ALS_UVS_THRES_LOW_2) & 0x0F;
+    value <<= 8;
+    value += readRegister(LTR390_ALS_UVS_THRES_LOW_1);
+    value <<= 8;
+    value += readRegister(LTR390_ALS_UVS_THRES_LOW_0);
+    return value;
+  }
+*/
+
+
+  //////////////////////////////////////////////
+  //
+  //  PRIVATE  TODO move.
+  //
+  int writeRegister(uint8_t reg, uint16_t value)
+  {
+    _wire->beginTransmission(_address);
+    _wire->write(reg);
+    _wire->write(value & 0xFF);
+    _wire->write(value >> 8);
+    int n = _wire->endTransmission();
+    if (n != 0)
+    {
+      //  Serial.print("write:\t");
+      //  Serial.println(n);
+    }
+    return n;
+  }
+
+
+  uint16_t readRegister(uint8_t reg)
+  {
+    _wire->beginTransmission(_address);
+    _wire->write(reg);
+    int n = _wire->endTransmission();
+    if (n != 0)
+    {
+      //  Serial.print("read:\t");
+      //  Serial.println(n);
+      return n;
+    }
+
+    n = _wire->requestFrom(_address, (uint8_t)2);
+    if (n != 2)
+    {
+      //  Serial.print("requestFrom: \t");
+      //  Serial.print(n);
+      return n;
+    }
+    uint16_t data = _wire->read();
+    return data + _wire->read() * 256;
+  }
+
+
+private:
+  TwoWire * _wire;
+  uint8_t _address;
+
+  //  for LUX math
+  float   _gain;
+  float   _time;
+  float   _UVsensitivity;
+};
+
+
+
+
+//  -- END OF FILE --
+
diff --git a/libraries/LTR390_DFR/README.md b/libraries/LTR390_DFR/README.md
new file mode 100644
index 00000000..12ee81f3
--- /dev/null
+++ b/libraries/LTR390_DFR/README.md
@@ -0,0 +1,141 @@
+
+[![Arduino CI](https://github.com/RobTillaart/LTR390_DFR/workflows/Arduino%20CI/badge.svg)](https://github.com/marketplace/actions/arduino_ci)
+[![Arduino-lint](https://github.com/RobTillaart/LTR390_DFR/actions/workflows/arduino-lint.yml/badge.svg)](https://github.com/RobTillaart/LTR390_DFR/actions/workflows/arduino-lint.yml)
+[![JSON check](https://github.com/RobTillaart/LTR390_DFR/actions/workflows/jsoncheck.yml/badge.svg)](https://github.com/RobTillaart/LTR390_DFR/actions/workflows/jsoncheck.yml)
+[![GitHub issues](https://img.shields.io/github/issues/RobTillaart/LTR390_DFR.svg)](https://github.com/RobTillaart/LTR390_DFR/issues)
+
+[![License: MIT](https://img.shields.io/badge/license-MIT-green.svg)](https://github.com/RobTillaart/LTR390_DFR/blob/master/LICENSE)
+[![GitHub release](https://img.shields.io/github/release/RobTillaart/LTR390_DFR.svg?maxAge=3600)](https://github.com/RobTillaart/LTR390_DFR/releases)
+[![PlatformIO Registry](https://badges.registry.platformio.org/packages/robtillaart/library/LTR390_DFR.svg)](https://registry.platformio.org/libraries/robtillaart/LTR390_DFR)
+
+
+# LTR390_DFR
+
+Arduino library for the I2C LTR390 UV sensor (DF Robotics edition).
+
+
+## Description
+
+**Experimental**
+
+This library is to read the LTR390 UV sensor on the DF Robotics
+break-out board.
+
+Operating voltage range: **3.0V .. 5.0V** (tolerant).
+
+
+## I2C
+
+The break-out has an address of 0x1C == 28 decimal.
+
+#### I2C Speed
+
+The device should work on 100 kHz and 400 kHz I2C bus.
+
+To be tested.
+
+
+#### Multiplexing
+
+Sometimes you need to control more devices than possible with the default
+address range the device provides.
+This is possible with an I2C multiplexer e.g. TCA9548 which creates up
+to eight channels (think of it as I2C subnets) which can use the complete
+address range of the device.
+
+Drawback of using a multiplexer is that it takes more administration in
+your code e.g. which device is on which channel.
+This will slow down the access, which must be taken into account when
+deciding which devices are on which channel.
+Also note that switching between channels will slow down other devices
+too if they are behind the multiplexer.
+
+- https://github.com/RobTillaart/TCA9548
+
+
+
+#### Related
+
+- https://github.com/RobTillaart/LTR390_RT   (native LTR390)
+- https://github.com/RobTillaart/LTR390_DFR  (DF Robotics variant)
+
+
+## Interface   TODO elaborate...
+
+```cpp
+#include "LTR390_DFR.h"
+```
+
+#### Constructor
+
+- **LTR390_DFR(TwoWire \* wire = &Wire)** Constructor 
+with optional Wire interface.
+- **bool begin()** returns true if device 0x1C can be seen on the I2C bus.
+- **bool isConnected()** returns true if device 0x1C can be seen on I2C bus.
+- **uint8_t getAddress()** returns 0x1C, fixed address, for convenience.
+
+
+#### Main control
+
+- **void setALSMode()**
+- **void setUVSMode()**
+- **void reset()** blocks for 100 ms.
+
+
+#### Measurement configuration
+
+- **void setGain(uint8_t gain)** gain = 0..4,
+- **uint8_t getGain()** returns set value.
+- **void setMeasurement(uint8_t resolution, uint8_t time)**
+- **uint8_t getResolution()**
+- **uint8_t getTime()**
+
+
+#### Part and revision ID
+
+- **uint8_t getPartID()** returns 11.
+- **uint8_t getRevisionID()** returns 2.
+
+
+#### Get data
+
+- **uint32_t getALSData()**
+- **float getLUX(float wfac = 1)** wfac = window factor,
+- **uint32_t getUVSData()**
+- **float getUVI(float wfac = 1)** wfac = window factor,
+
+
+## Future
+
+#### Must
+
+- Elaborate and improve documentation a lot.
+  - add tables, ranges etc.
+- test with right hardware.
+- keep in sync with LTR390_RT when possible
+
+#### Should
+
+- add examples
+- fix / elaborate TODO's in code.
+  - status and error codes
+  - interrupts and thresholds
+- add setUVsensitivity()
+
+#### Could
+
+- add error handling
+- unit test ==> test examples
+
+#### Wont
+
+
+## Support
+
+If you appreciate my libraries, you can support the development and maintenance.
+Improve the quality of the libraries by providing issues and Pull Requests, or
+donate through PayPal or GitHub sponsors.
+
+Thank you,
+
+
diff --git a/libraries/LTR390_DFR/examples/LTR390_ALS_demo/LTR390_ALS_demo.ino b/libraries/LTR390_DFR/examples/LTR390_ALS_demo/LTR390_ALS_demo.ino
new file mode 100644
index 00000000..d4de5630
--- /dev/null
+++ b/libraries/LTR390_DFR/examples/LTR390_ALS_demo/LTR390_ALS_demo.ino
@@ -0,0 +1,56 @@
+//
+//    FILE: LTR390_ALS_demo.ino
+//  AUTHOR: Rob Tillaart
+// PURPOSE: test basic behaviour and performance
+//     URL: https://github.com/RobTillaart/LTR390_DFR
+//
+//  can be used with plotter.
+
+#include "LTR390_DFR.h"
+
+
+LTR390_DFR uv;
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println();
+  Serial.println(__FILE__);
+  Serial.println();
+  Serial.print("LTR390_DFR_LIB_VERSION: ");
+  Serial.println(LTR390_DFR_LIB_VERSION);
+  Serial.println();
+
+  Wire.begin();
+
+  uv.begin();
+
+  while (uv.isConnected() == false)
+  {
+    Serial.println("Could not connect, fix and reboot");
+    delay(1000);
+  }
+  Serial.println("Device found.");
+
+  Serial.print("RESET:\t");
+  Serial.println(uv.reset());
+  Serial.print("PARTID:\t");
+  Serial.println(uv.getPartID());
+  Serial.print("REVID:\t");
+  Serial.println(uv.getRevisionID());
+
+  uv.setALSMode();
+  delay(1000);
+
+  Serial.println("End setup...");
+}
+
+
+void loop()
+{
+  delay(1000);
+  Serial.println(uv.getALSData());
+}
+
+
+//  -- END OF FILE --
diff --git a/libraries/LTR390_DFR/examples/LTR390_UV_demo/LTR390_UV_demo.ino b/libraries/LTR390_DFR/examples/LTR390_UV_demo/LTR390_UV_demo.ino
new file mode 100644
index 00000000..55f677f8
--- /dev/null
+++ b/libraries/LTR390_DFR/examples/LTR390_UV_demo/LTR390_UV_demo.ino
@@ -0,0 +1,52 @@
+//
+//    FILE: LTR390_UV_demo.ino
+//  AUTHOR: Rob Tillaart
+// PURPOSE: test basic behaviour and performance
+//     URL: https://github.com/RobTillaart/LTR390
+
+
+#include "LTR390_DFR.h"
+
+
+LTR390_DFR uv;
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println();
+  Serial.println(__FILE__);
+  Serial.println();
+  Serial.print("LTR390_DFR_LIB_VERSION: ");
+  Serial.println(LTR390_DFR_LIB_VERSION);
+  Serial.println();
+
+  Wire.begin();
+
+  if (uv.begin() == false)
+  {
+    Serial.println("Could not connect, fix and reboot");
+  }
+  else
+  {
+    Serial.println("Device found.");
+  }
+
+  Serial.print("PARTID:\t");
+  Serial.println(uv.getPartID());
+  Serial.print("REVID:\t");
+  Serial.println(uv.getRevisionID());
+
+  uv.setUVSMode();
+
+  Serial.println("\ndone...");
+}
+
+
+void loop()
+{
+  delay(1000);
+  Serial.println(uv.getUVSData());
+}
+
+
+//  -- END OF FILE --
diff --git a/libraries/LTR390_DFR/examples/LTR390_dump_registers/LTR390_dump_registers.ino b/libraries/LTR390_DFR/examples/LTR390_dump_registers/LTR390_dump_registers.ino
new file mode 100644
index 00000000..d9f84deb
--- /dev/null
+++ b/libraries/LTR390_DFR/examples/LTR390_dump_registers/LTR390_dump_registers.ino
@@ -0,0 +1,67 @@
+//
+//    FILE: LTR390_dump_registers.ino
+//  AUTHOR: Rob Tillaart
+// PURPOSE: dump
+//     URL: https://github.com/RobTillaart/LTR390_DFR
+
+
+#include "LTR390_DFR.h"
+
+
+LTR390_DFR uv;
+
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println();
+  Serial.println(__FILE__);
+  Serial.println();
+  Serial.print("LTR390_DFR_LIB_VERSION: ");
+  Serial.println(LTR390_DFR_LIB_VERSION);
+  Serial.println();
+
+  Wire.begin();
+  Wire.setClock(100000);
+
+  if (uv.begin() == false)
+  {
+    Serial.println("Could not connect, fix and reboot");
+  }
+  else
+  {
+    Serial.println("Device found.");
+  }
+
+  //  register range according to DFrobotics
+  for (uint8_t reg = 0x00; reg < 0x14; reg++)
+  {
+    Serial.print(reg, HEX);
+    Serial.print("\t");
+    Serial.print(uv.readRegister(reg), HEX);
+    Serial.print("\t(");
+    Serial.print(uv.readRegister(reg));
+    Serial.print(")\n");
+  }
+  Serial.println();
+
+  Serial.println("\ndone...");
+
+  //  select mode
+  //  uv.setUVSMode();
+  uv.setALSMode();
+}
+
+
+void loop()
+{
+  //  Serial.print("ALS:\t");
+  //  Serial.println(uv.getALSData());
+  //  delay(1000);
+  //  Serial.print("UVS:\t");
+  //  Serial.println(uv.getUVSData());
+  //  delay(1000);
+}
+
+
+//  -- END OF FILE --
diff --git a/libraries/LTR390_DFR/examples/LTR390_getLux/LTR390_getLux.ino b/libraries/LTR390_DFR/examples/LTR390_getLux/LTR390_getLux.ino
new file mode 100644
index 00000000..fa992653
--- /dev/null
+++ b/libraries/LTR390_DFR/examples/LTR390_getLux/LTR390_getLux.ino
@@ -0,0 +1,50 @@
+//
+//    FILE: LTR390_getLux.ino
+//  AUTHOR: Rob Tillaart
+// PURPOSE: test basic behaviour and performance
+//     URL: https://github.com/RobTillaart/LTR390_DFR
+//
+//  can be used with plotter.
+
+#include "LTR390_DFR.h"
+
+
+LTR390_DFR uv;
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println();
+  Serial.println(__FILE__);
+  Serial.println();
+  Serial.print("LTR390_DFR_LIB_VERSION: ");
+  Serial.println(LTR390_DFR_LIB_VERSION);
+  Serial.println();
+
+  Wire.begin();
+
+  uv.begin();
+
+  while (uv.isConnected() == false)
+  {
+    Serial.println("Could not connect, fix and reboot");
+    delay(1000);
+  }
+  Serial.println("Device found.");
+
+  uv.setALSMode();
+
+  Serial.println("RAW, LUX");
+}
+
+
+void loop()
+{
+  delay(1000);
+  Serial.print(uv.getALSData());
+  Serial.print("\t");
+  Serial.println(uv.getLux());
+}
+
+
+//  -- END OF FILE --
diff --git a/libraries/LTR390_DFR/keywords.txt b/libraries/LTR390_DFR/keywords.txt
new file mode 100644
index 00000000..70c98cb9
--- /dev/null
+++ b/libraries/LTR390_DFR/keywords.txt
@@ -0,0 +1,34 @@
+# Syntax Colouring Map For LTR390_DFR
+
+# Data types (KEYWORD1)
+LTR390_DFR	KEYWORD1
+
+
+# Methods and Functions (KEYWORD2)
+begin	KEYWORD2
+isConnected	KEYWORD2
+getAddress	KEYWORD2
+
+setALSMode	KEYWORD2
+setUVSMode	KEYWORD2
+reset	KEYWORD2
+
+getPartID	KEYWORD2
+getRevisionID	KEYWORD2
+
+getALSData	KEYWORD2
+getLUX	KEYWORD2
+getUVSData	KEYWORD2
+getUVI	KEYWORD2
+
+setGain	KEYWORD2
+getGain	KEYWORD2
+
+setMeasurement	KEYWORD2
+getResolution	KEYWORD2
+getTime	KEYWORD2
+
+
+# Constants (LITERAL1)
+LTR390_DFR_LIB_VERSION	LITERAL1
+
diff --git a/libraries/LTR390_DFR/library.json b/libraries/LTR390_DFR/library.json
new file mode 100644
index 00000000..c61d2264
--- /dev/null
+++ b/libraries/LTR390_DFR/library.json
@@ -0,0 +1,23 @@
+{
+  "name": "LTR390_DFR",
+  "keywords": "UV, LUX",
+  "description": "Arduino library for the I2C LTR390 UV sensor. (DF Robotics edition)",
+  "authors":
+  [
+    {
+      "name": "Rob Tillaart",
+      "email": "Rob.Tillaart@gmail.com",
+      "maintainer": true
+    }
+  ],
+  "repository":
+  {
+    "type": "git",
+    "url": "https://github.com/RobTillaart/LTR390_DFR.git"
+  },
+  "version": "0.1.0",
+  "license": "MIT",
+  "frameworks": "*",
+  "platforms": "*",
+  "headers": "LTR390_DFR.h"
+}
diff --git a/libraries/LTR390_DFR/library.properties b/libraries/LTR390_DFR/library.properties
new file mode 100644
index 00000000..4ed3d310
--- /dev/null
+++ b/libraries/LTR390_DFR/library.properties
@@ -0,0 +1,11 @@
+name=LTR390_DFR
+version=0.1.0
+author=Rob Tillaart <rob.tillaart@gmail.com>
+maintainer=Rob Tillaart <rob.tillaart@gmail.com>
+sentence=Arduino library for the I2C LTR390 UV sensor (DF Robotics edition).
+paragraph=
+category=Sensors
+url=https://github.com/RobTillaart/LTR390_DFR
+architectures=*
+includes=LTR390_DFR.h
+depends=
diff --git a/libraries/LTR390_DFR/test/unit_test_001.cpp b/libraries/LTR390_DFR/test/unit_test_001.cpp
new file mode 100644
index 00000000..4854a990
--- /dev/null
+++ b/libraries/LTR390_DFR/test/unit_test_001.cpp
@@ -0,0 +1,51 @@
+//
+//    FILE: unit_test_001.cpp
+//  AUTHOR: Rob Tillaart
+//    DATE: 2024-04-29
+// PURPOSE: unit tests for the LTR390 library
+//     URL: https://github.com/RobTillaart/LTR390_DFR
+//
+
+// supported assertions
+// https://github.com/Arduino-CI/arduino_ci/blob/master/cpp/unittest/Assertion.h#L33-L42
+// ----------------------------
+// assertEqual(expected, actual)
+// assertNotEqual(expected, actual)
+// assertLess(expected, actual)
+// assertMore(expected, actual)
+// assertLessOrEqual(expected, actual)
+// assertMoreOrEqual(expected, actual)
+// assertTrue(actual)
+// assertFalse(actual)
+// assertNull(actual)
+// assertNotNull(actual)
+
+#include <ArduinoUnitTests.h>
+
+#include "LTR390_DFR.h"
+
+
+unittest_setup()
+{
+  fprintf(stderr, "LTR390_DFR_LIB_VERSION: %s\n", (char *) LTR390_DFR_LIB_VERSION);
+}
+
+
+unittest_teardown()
+{
+}
+
+
+unittest(test_constructor)
+{
+  LTR390_DFR dev;
+
+  assertEqual(0x1C, dev.getAddress());
+}
+
+
+unittest_main()
+
+
+//  -- END OF FILE --
+