diff --git a/.clang-format b/.clang-format
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--- /dev/null
+++ b/.clang-format
@@ -0,0 +1,4 @@
+Language: Cpp
+BasedOnStyle:  WebKit
+BreakBeforeBraces: Attach
+NamespaceIndentation: None
diff --git a/API.md b/API.md
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+++ b/API.md
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+# TroykaPH API
+
+## `class TroykaPH`
+
+Create an object of type `TroykaPH` to control the [module for measuring pH of liquids TroykaPH] (https://amperka.ru/product/troyka-ph-sensor).
+
+### `TroykaPH(uint8_t pin)`
+
+Creates a new TroykaPH object.
+
+- `pin`: analog pin to which the module is connected.
+
+### `void begin(float correction = 1.0, float zeroShift = 2.0)`
+
+- `correction` - AVR's internal voltage reference offset correction.
+- `zeroShift` - correction of the real shift `0` during measurements.
+
+Initializes the library. Call this method before you begin interacting with TroykaPH. For example, in the `setup()`.
+
+- `correctionMultiplier`: correction factor obtained as a result of the calibration procedure. If absent, it is taken equal to `1`.
+
+### `void update(long periodMilliseconds = 1000)`
+
+Performs periodic reading of sensor and correction factors. Place his call in `loop()`.
+
+- `periodMilliseconds`: sensor polling period.
+
+### `float read() const;`
+
+Returns the last measured pH value.
diff --git a/API_ru.md b/API_ru.md
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--- /dev/null
+++ b/API_ru.md
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+# TroykaPH API (RUS)
+
+## `class TroykaPH`
+
+Создайте объект типа `TroykaPH` для управления [модулем измерения pH жидкостей TroykaPH](https://amperka.ru/product/troyka-ph-sensor).
+
+### `TroykaPH(uint8_t pin)`
+
+Создает новый объект TroykaPH.
+
+- `pin`: аналоговый пин к которому подключен модуль.
+
+### `void begin(float correction = 1.0, float zeroShift = 2.0)`
+
+- `correction` - коррекция с учетом сдвига напряжения внутреннего источника опорного напряжения AVR.
+- `zeroShift` - коррекция с учетом реального сдвига `0` при измерениях.
+
+Инициализирует библиотеку. Вызовите этот метод до начала взаимодействия с TroykaPH. Например в функции `setup()`.
+
+- `correctionMultiplier`: корректировочный множитель полученный в результате процедуры калибровки. При отсутствии принимается равным `1`.
+
+### `void update(long periodMilliseconds = 1000)`
+
+Производит периодическое чтение показаний датчика и корректировочных коэфициентов. Разместите его вызов в `loop()`.
+
+- `periodMilliseconds`: период опроса датчика.
+
+### `float read() const;`
+
+Возвращает последнее замеренное значение pH.
diff --git a/examples/calibrate/calibrate.ino b/examples/calibrate/calibrate.ino
new file mode 100644
index 0000000..47ef253
--- /dev/null
+++ b/examples/calibrate/calibrate.ino
@@ -0,0 +1,102 @@
+/*
+
+  Берем плату Arduino или совместимую, подключаем по USB, прошиваем этим скетчем и
+  запускаем скетч. Выполняем указания в Serial Monitor.
+
+  Важно: надо ввести в Serial Monitor значение в милливольтах - 4 цифры, незначащие
+  правые дополнить нулями.
+
+*/
+
+/*
+  This example don't use library. It demonstrates TroykaPH calibration procedure
+*/
+
+float measureVop() {
+#if defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
+    ADMUX = _BV(REFS0) | _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
+#elif defined(__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)
+    ADMUX = _BV(MUX5) | _BV(MUX0);
+#elif defined(__AVR_ATtiny25__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
+    ADMUX = _BV(MUX3) | _BV(MUX2);
+#else
+    ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
+#endif
+    delay(75);
+    float Vop = 0;
+    for (uint8_t i = 0; i < 100; i++) {
+        ADCSRA |= _BV(ADSC);
+        while (bit_is_set(ADCSRA, ADSC))
+            ;
+        uint8_t low = ADCL;
+        uint8_t high = ADCH;
+
+        Vop += (float)((high << 8) | low) * 5. / 1024.;
+        delay(10);
+    }
+    return Vop / 100.;
+}
+
+float measureZeroLevel() {
+    (void)analogRead(A4);
+    float Vzero = 0;
+    for (uint8_t i = 0; i < 100; i++) {
+        Vzero += (float)analogRead(A4) * 5. / 1024.;
+        delay(10);
+    }
+    return Vzero / 100.;
+}
+
+float factor;
+
+void setup() {
+    Serial.begin(9600);
+    while (!Serial)
+        ;
+
+    Serial.print("\n\n\nTroyka pH module zero-shift calibration procedure\n\n");
+    Serial.print("- Connect TroykaPH module to Arduino board.\n");
+    Serial.print("- Shortcut TroykaPH module BNC input to ground.\n");
+    Serial.print("- Measure (using good multimeter) Arduino board feed voltage between 5V and GND pins\n");
+    Serial.print("- Input this value in millivolts to Serial Monitor input line, press 'Send' after it.\n");
+    Serial.print("For example: if measured value is '4.93' volts - punch '4930'\n\n");
+}
+
+void loop() {
+    if (Serial.available() > 0) {
+        float Vmeasured = (float)Serial.parseInt() / 1000;
+        if (Vmeasured == 0)
+            return;
+        Serial.print("Voltage measured by multimeter (V) = ");
+        Serial.println(Vmeasured, 3);
+        float Vop = measureVop();
+        Serial.print("Voltage of internal reference  (V) = ");
+        Serial.println(Vop, 3);
+        float VccCalculated = Vop * 5. / 1.1;
+        Serial.print("Calculated Vcc                 (V) = ");
+        Serial.println(VccCalculated, 3);
+
+        factor = (float)(VccCalculated) / (float)(Vmeasured);
+
+        float VccReal = 5. / factor;
+        Serial.print("Real Vcc                       (V) = ");
+        Serial.println(VccReal, 3);
+
+        float Vzero = measureZeroLevel();
+        Serial.print("Calculated zero-shift voltage  (V) = ");
+        Serial.println(Vzero, 3);
+        float VzeroReal = Vzero / factor;
+        Serial.print("Real zero-shift voltage        (V) = ");
+        Serial.println(VzeroReal, 3);
+
+        Serial.print("Calibration complete.");
+        Serial.print("\n\nCall in your 'setup()' method {your-pH-sensor-name}.begin(");
+        Serial.print(factor, 3);
+        Serial.print(", ");
+        Serial.print(VzeroReal, 3);
+        Serial.print("); \n\n");
+
+        Serial.println("Recalibration is needed if you change Arduino board to another.\n\n");
+        delay(5000);
+    }
+}
diff --git a/examples/simpleReadPH/simpleReadPH.ino b/examples/simpleReadPH/simpleReadPH.ino
new file mode 100644
index 0000000..9af5323
--- /dev/null
+++ b/examples/simpleReadPH/simpleReadPH.ino
@@ -0,0 +1,32 @@
+/*
+  This example demonstrate pH value reading
+*/
+#include "Arduino.h"
+
+// Include library
+#include "TroykaPH.h"
+
+TroykaPH phMeter(A4); // set used analog pin
+
+uint32_t lastShowingTime;
+constexpr uint32_t INTERVAL = 3000;
+
+void setup() {
+    phMeter.begin(); // if module not calibrated or...
+    // phMeter.begin(correction,zeroShift); // if you have it (use calibrate.ino) for it
+
+    Serial.begin(9600);
+    lastShowingTime = millis(); // show result once per 3 seconds
+}
+
+void loop() {
+    uint32_t currentTime = millis();
+    phMeter.update(1000); // real read from sensor once per second
+    // (you can increase this period, in practice pH value changing too slowly)
+
+    if (currentTime - lastShowingTime > INTERVAL) {
+        lastShowingTime = currentTime;
+        Serial.print("\nCurrent pH: ");
+        Serial.print(phMeter.read(), 1);
+    }
+}
diff --git a/keywords.txt b/keywords.txt
new file mode 100644
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--- /dev/null
+++ b/keywords.txt
@@ -0,0 +1,21 @@
+#######################################
+# Syntax Coloring Map TroykaPH
+#######################################
+
+#######################################
+# Datatypes (KEYWORD1)
+#######################################
+
+TroykaPH	KEYWORD1
+
+#######################################
+# Methods and Functions (KEYWORD2)
+#######################################
+
+begin			KEYWORD2
+update			KEYWORD2
+read		        KEYWORD2
+
+#######################################
+# Constants (LITERAL1)
+#######################################
diff --git a/library.properties b/library.properties
new file mode 100644
index 0000000..7ff1c48
--- /dev/null
+++ b/library.properties
@@ -0,0 +1,9 @@
+name=TroykaPH
+version=1.0.0
+author=Yury Botov <by@amperka.ru>
+maintainer=Amperka <amperka.ru>
+sentence=Library for TroykaPH sensor.
+paragraph=Allows calibrate and read sensor value
+category=Sensor
+url=https://github.com/amperka/TroykaPH
+architectures=*
diff --git a/src/TroykaPH.cpp b/src/TroykaPH.cpp
new file mode 100644
index 0000000..8d8f760
--- /dev/null
+++ b/src/TroykaPH.cpp
@@ -0,0 +1,89 @@
+/*
+ * This file is a part of TroykaPH library.
+ *
+ * Product page: https://amperka.ru/product/troyka-ph-sensor
+ * © Amperka LLC (https://amperka.com, dev@amperka.com)
+ * 
+ * Author: Yury Botov <by@amperka.com>
+ * License: GPLv3, all text here must be included in any redistribution.
+ */
+
+#include "TroykaPH.h"
+
+TroykaPH::TroykaPH(uint8_t pin) {
+    _pin = pin;
+    _lastValue = 7;
+    _correction = 1.0;
+    _nextMeasureTime = 0;
+}
+
+void TroykaPH::begin(float correction, float zeroLevel) {
+    _correction = correction;
+    _zeroLevel = zeroLevel;
+}
+
+static float fmap(float value, float minVal, float maxVal, float minOut, float maxOut) {
+    return (value - minVal) / (maxVal - minVal) * (maxOut - minOut) + minOut;
+}
+
+void TroykaPH::update(long periodMilliseconds) {
+    constexpr float idealVcc = 5.0;
+    constexpr float minPh = 0.0;
+    constexpr float maxPh = 14.0;
+    constexpr float phHalfRangeInVolts = 0.82;
+
+    float value = 0;
+    if (millis() - _nextMeasureTime > periodMilliseconds) {
+        _nextMeasureTime += periodMilliseconds;
+        // read value
+        (void)analogRead(_pin);
+        delay(75);
+        for (uint8_t i = 0; i < 10; i++) {
+            value += (float)analogRead(_pin) * 5.0 / 1024.;
+        }
+        value = value / 10;
+        // read real Vcc value
+        float realVcc = (float)(_readVcc()) / 1000.;
+
+        float result = value * idealVcc / realVcc;
+        result /= _correction; // internal reference source correction
+
+        _lastValue = fmap(result, _zeroLevel - phHalfRangeInVolts, _zeroLevel + phHalfRangeInVolts, minPh, maxPh);
+    }
+}
+
+float TroykaPH::read() const { return _lastValue; }
+
+long TroykaPH::_readVcc() {
+    constexpr float adcResolution = 1024.;
+    constexpr float meanReferenceVoltage = 1.1;
+    constexpr long toMillivolts = 1000L;
+
+    long result = 0;
+#if defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
+    ADMUX = _BV(REFS0) | _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
+#elif defined(__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)
+    ADMUX = _BV(MUX5) | _BV(MUX0);
+#elif defined(__AVR_ATtiny25__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
+    ADMUX = _BV(MUX3) | _BV(MUX2);
+#else
+    ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
+#endif
+
+    delay(75);
+    // internal reference reading
+    for (uint8_t i = 0; i < 10; i++) {
+        ADCSRA |= _BV(ADSC);
+        while (bit_is_set(ADCSRA, ADSC))
+            ;
+
+        uint8_t low = ADCL;
+        uint8_t high = ADCH;
+
+        result += (high << 8) | low;
+    }
+    result /= 10;
+
+    result = (long)(adcResolution * meanReferenceVoltage) * toMillivolts / result;
+    return result;
+}
diff --git a/src/TroykaPH.h b/src/TroykaPH.h
new file mode 100644
index 0000000..7ee542e
--- /dev/null
+++ b/src/TroykaPH.h
@@ -0,0 +1,34 @@
+/*
+ * This file is a part of TroykaPH library.
+ *
+ * Product page: https://amperka.ru/product/zelo-folow-line-sensor
+ * © Amperka LLC (https://amperka.com, dev@amperka.com)
+ * 
+ * Author: Yury Botov <by@amperka.com>
+ * License: GPLv3, all text here must be included in any redistribution.
+ */
+
+#ifndef __TROYKA_PH_H__
+#define __TROYKA_PH_H__
+
+#include "Arduino.h"
+
+class TroykaPH {
+public:
+    TroykaPH(uint8_t pin);
+    void begin(float correction = 1.0, float zeroLevel = 2.0);
+
+    void update(long periodMilliseconds = 1000);
+
+    float read() const;
+
+private:
+    uint8_t _pin;
+    float _lastValue;
+    float _correction;
+    float _zeroLevel;
+    uint32_t _nextMeasureTime;
+    long _readVcc();
+};
+
+#endif //__TROYKA_PH_H__