diff --git a/lib/Domain/Gun/Atmega328pHal.hpp b/lib/Domain/Gun/Atmega328pHal.hpp
new file mode 100644
index 0000000..c016ee7
--- /dev/null
+++ b/lib/Domain/Gun/Atmega328pHal.hpp
@@ -0,0 +1,86 @@
+/*
+ *
+ * Copyright (c) 2023 Aurélien Labrosse
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+#include <Gun/IGunHal.hpp>
+#include <avr/io.h>
+
+#define BSP_TICKS_PER_SEC 100
+#define F_CPU 16000000L
+
+#define LASER_PIN 10
+#define VIBRATOR_PIN 6
+#define BATTERY_VOLTAGE_PIN A3
+#define CHARGING_STATE_PIN A2
+
+#define MIN_BAT_VOLTAGE 3000
+#define MAX_BAT_VOLTAGE 4120
+
+ISR(TIMER2_COMPA_vect) {}
+
+class Atmega328pHal : public IGunHal {
+public:
+  ~Atmega328pHal() {}
+
+  Atmega328pHal() {
+
+    pinMode(VIBRATOR_PIN, OUTPUT);
+    pinMode(LASER_PIN, OUTPUT);
+  }
+  /*
+   * the 'loop' method shall be called each 10ms
+   *
+   * Configure timer2 so that an interrupt occurs each 10ms
+   * and wake up the MCU if it is in sleep mode.
+   */
+  void setupHeartbeat() override {
+    TCCR2A = (1U << WGM21) | (0U << WGM20); // set Timer2 in CTC mode
+    TCCR2B = (1U << CS22) | (1U << CS21) | (1U << CS20); // 1/1024 prescaler
+    ASSR &= ~(1U << AS2);
+    TIMSK2 = (1U << OCIE2A); // enable TIMER2 compare Interrupt
+    TCNT2 = 0U;
+
+    // set the output-compare register based on the desired tick frequency
+    OCR2A = (F_CPU / BSP_TICKS_PER_SEC / 1024U) - 1U;
+  }
+
+  void laserOn() override { PORTB |= (1 << PB2); }
+  void laserOff() override { PORTB &= ~(1 << PB2); }
+  void vibrationOn() override { PORTD |= (1 << PD6); }
+  void vibrationOff() override { PORTD &= ~(1 << PD6); }
+
+  uint16_t getBatteryVoltageMv() override {
+
+    analogRead(BATTERY_VOLTAGE_PIN);
+    float rawBatt = analogRead(BATTERY_VOLTAGE_PIN);
+    rawBatt += analogRead(BATTERY_VOLTAGE_PIN);
+    rawBatt += analogRead(BATTERY_VOLTAGE_PIN);
+    rawBatt += analogRead(BATTERY_VOLTAGE_PIN);
+    rawBatt /= 4;
+    uint16_t battMv = (5000 / 1023.f) * rawBatt;
+
+    return battMv;
+  };
+
+  uint8_t getBatteryVoltagePercent() override {
+    return map(getBatteryVoltageMv(), MIN_BAT_VOLTAGE, MAX_BAT_VOLTAGE, 0, 100);
+  }
+
+  virtual bool isCharging() override {
+    return (digitalRead(CHARGING_STATE_PIN) == HIGH);
+  }
+};
\ No newline at end of file
diff --git a/lib/Domain/Gun/Button.cpp b/lib/Domain/Gun/Button.cpp
new file mode 100644
index 0000000..93ceeba
--- /dev/null
+++ b/lib/Domain/Gun/Button.cpp
@@ -0,0 +1,18 @@
+/*
+ *
+ * Copyright (c) 2023 Aurélien Labrosse
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <Gun/Button.hpp>
diff --git a/lib/Domain/Gun.cpp b/lib/Domain/Gun/Button.hpp
similarity index 58%
rename from lib/Domain/Gun.cpp
rename to lib/Domain/Gun/Button.hpp
index 40f5832..527c2c3 100644
--- a/lib/Domain/Gun.cpp
+++ b/lib/Domain/Gun/Button.hpp
@@ -1,39 +1,28 @@
-/*
- *
- * Copyright (c) 2023 Aurélien Labrosse
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, version 3.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-#include <Gun.hpp>
-
-static const uint8_t SHOTS_PER_REARM = 5;
-
-void Gun::onButton1ShortPress() {
-  if (availableShots > 0) {
-    _hal.laserOn();
-    _hal.vibrationOn();
-    _hal.shortDelay();
-    _hal.laserOff();
-    _hal.vibrationOff();
-    availableShots--;
-  }
-  
-}
-
-void Gun::onButton1LongPress() {
-    _hal.deepSleep();
-}
-void Gun::onButton2ShortPress() { availableShots = SHOTS_PER_REARM; }
-void Gun::onButton2LongPress() {
-    _hal.laserOn();
-}
+/*
+ *
+ * Copyright (c) 2023 Aurélien Labrosse
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+#include <Contactor.hpp>
+
+class Button : public Contactor {
+
+public:
+  Button() : Contactor(), calibrationMode(false) {}
+
+  bool calibrationMode;
+  void onShortPress() override { shootCount = 0; }
+  void onLongPress() override { calibrationMode = !calibrationMode; }
+};
\ No newline at end of file
diff --git a/lib/Domain/Gun/Gun.cpp b/lib/Domain/Gun/Gun.cpp
new file mode 100644
index 0000000..539bfed
--- /dev/null
+++ b/lib/Domain/Gun/Gun.cpp
@@ -0,0 +1,143 @@
+/*
+ *
+ * Copyright (c) 2023 Aurélien Labrosse
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <Contactor.hpp>
+#include <Gun.hpp>
+#include <LowPower.h>
+
+volatile uint16_t hitcount;
+uint16_t previoushitcout;
+volatile uint16_t shootCount;
+
+#define TICKS_BETWEEN_UI_UPDATE 10
+
+// display API
+static void displayBatteryStatus();
+static void displayShootCount();
+
+void setup();
+static void setupHeartbeat();
+
+// counter for ticks between battery display update
+uint16_t updateBatteryDisplayCycleCount;
+
+Trigger trigger;
+Button button;
+
+volatile Contactor::Event pendingTriggerEvent;
+void triggerInterruptHandler() {
+  if (bit_is_set(PIND, PD2)) {
+    pendingTriggerEvent = Contactor::Event::Released;
+  } else {
+    pendingTriggerEvent = Contactor::Event::Pressed;
+  }
+}
+
+volatile Contactor::Event pendingButtonEvent;
+void buttonInterruptHandler() {
+  if (bit_is_set(PIND, PD3)) {
+    pendingButtonEvent = Contactor::Event::Released;
+  } else {
+    pendingButtonEvent = Contactor::Event::Pressed;
+  }
+}
+
+long now = 0;
+
+void Gun::loop(void) {
+
+  now += 10; // 10ms per loop thanks to timer2
+
+  trigger.decreaseCycleCount();
+
+  cli();
+  trigger.pendingEvent = pendingTriggerEvent;
+  button.pendingEvent = pendingButtonEvent;
+  pendingTriggerEvent = Contactor::Event::NoEvent;
+  pendingButtonEvent = Contactor::Event::NoEvent;
+  sei();
+
+  trigger.processPendingEvent(now);
+  button.processPendingEvent(now);
+
+  button.checkForLongPress(now);
+
+  if (button.calibrationMode) {
+    hal->laserOn();
+    hal->vibrationOff();
+
+  } else {
+    if (trigger.shootCycleCountdown == 0) {
+      hal->laserOff();
+      hal->vibrationOff();
+      ui->displayShootCount(shootCount);
+    }
+
+    if (updateBatteryDisplayCycleCount > 0) {
+      updateBatteryDisplayCycleCount--;
+    }
+    if (updateBatteryDisplayCycleCount == 0) {
+      displayBatteryStatus();
+      updateBatteryDisplayCycleCount = TICKS_BETWEEN_UI_UPDATE;
+    }
+  }
+
+  LowPower.idle(SLEEP_15MS, ADC_OFF, TIMER2_ON, TIMER1_ON, TIMER0_ON, SPI_OFF,
+                USART0_OFF, TWI_OFF);
+}
+
+
+void Gun::setup(void) {
+
+#if defined(SERIAL_OUTPUT)
+  Serial.begin(115200);
+  while (!Serial) {
+  }
+
+  shootCount = 0;
+  updateBatteryDisplayCycleCount = TICKS_BETWEEN_UI_UPDATE;
+
+  pinMode(LASER_PIN, OUTPUT);
+  digitalWrite(LASER_PIN, LOW);
+
+  pinMode(OUT2_PIN, OUTPUT);
+  digitalWrite(OUT2_PIN, LOW);
+
+  pinMode(BATTERY_VOLTAGE_PIN, INPUT);
+  pinMode(CHARGING_STATE_PIN, INPUT);
+
+  pinMode(LED_BUILTIN, OUTPUT);
+  digitalWrite(LED_BUILTIN, LOW);
+
+#if defined(SERIAL_OUTPUT)
+  Serial.println("Ready!");
+#endif
+
+  ui->displaySplash();
+  ui->displayBatteryStatus();
+  ui->displayShootCount();
+
+  pinMode(BUTTON2_PIN, INPUT_PULLUP);
+  attachInterrupt(digitalPinToInterrupt(BUTTON2_PIN), buttonInterruptHandler,
+                  CHANGE);
+
+  pinMode(TRIGGER_PIN, INPUT_PULLUP);
+  attachInterrupt(digitalPinToInterrupt(TRIGGER_PIN), triggerInterruptHandler,
+                  CHANGE);
+  cli();
+  setupHeartbeat();
+  sei();
+}
\ No newline at end of file
diff --git a/lib/Domain/Gun.hpp b/lib/Domain/Gun/Gun.hpp
similarity index 73%
rename from lib/Domain/Gun.hpp
rename to lib/Domain/Gun/Gun.hpp
index 4858b0b..cd6fb5f 100644
--- a/lib/Domain/Gun.hpp
+++ b/lib/Domain/Gun/Gun.hpp
@@ -16,18 +16,17 @@
  */
 #pragma once
 
-#include <IGunHal.hpp>
-#include <stdint.h>
+#include <Gun/IGunHal.hpp>
+#include <Gun/IGunUi.hpp>
 
 class Gun {
 
-  IGunHal &_hal;
+  IGunHal *hal;
+  IGunUi *ui;
 
 public:
-  uint8_t availableShots;
-  Gun(IGunHal &hal) : _hal(hal) {}
-  void onButton1ShortPress();
-  void onButton1LongPress();
-  void onButton2ShortPress();
-  void onButton2LongPress();
+  Gun(IGunHal *hal, IGunUi *ui) : hal(hal), ui(ui) {}
+
+  void loop();
+  void setup();
 };
\ No newline at end of file
diff --git a/lib/Domain/IGunHal.hpp b/lib/Domain/Gun/IGunHal.hpp
similarity index 78%
rename from lib/Domain/IGunHal.hpp
rename to lib/Domain/Gun/IGunHal.hpp
index 4891b53..e050679 100644
--- a/lib/Domain/IGunHal.hpp
+++ b/lib/Domain/Gun/IGunHal.hpp
@@ -16,18 +16,22 @@
  */
 #pragma once
 
+#include <stdint.h>
+
 class IGunHal {
 public:
   virtual ~IGunHal() {}
-  virtual bool isTriggerDown() = 0;
-  virtual bool isButtonDown() = 0;
-  virtual void shortDelay() = 0;
-  virtual void longDelay() = 0;
-  virtual void ledOn() = 0;
-  virtual void ledOff() = 0;
+
+  /*
+   * the 'loop' method shall be called each 10ms
+   */
+  virtual void setupHeartbeat() = 0;
+
   virtual void laserOn() = 0;
   virtual void laserOff() = 0;
   virtual void vibrationOn() = 0;
   virtual void vibrationOff() = 0;
-  virtual void deepSleep() = 0;
+  virtual uint16_t getBatteryVoltageMv() = 0;
+  virtual bool isCharging() = 0;
+
 };
\ No newline at end of file
diff --git a/lib/Domain/Gun/IGunUi.hpp b/lib/Domain/Gun/IGunUi.hpp
new file mode 100644
index 0000000..1933261
--- /dev/null
+++ b/lib/Domain/Gun/IGunUi.hpp
@@ -0,0 +1,26 @@
+/*
+ *
+ * Copyright (c) 2023 Aurélien Labrosse
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+class IGunUi {
+
+public:
+  virtual void displaySplash(uint16_t timeoutMs) = 0;
+  virtual void displayBatteryStatus(uint16_t mv, uint8_t percent) = 0;
+  virtual void displayChargingStatus(bool isCharging) = 0;
+  virtual void displayShootCount(uint16_t shootCount) = 0;
+};
\ No newline at end of file
diff --git a/lib/Domain/Gun/SSD1306Ui.hpp b/lib/Domain/Gun/SSD1306Ui.hpp
new file mode 100644
index 0000000..abc6486
--- /dev/null
+++ b/lib/Domain/Gun/SSD1306Ui.hpp
@@ -0,0 +1,94 @@
+/*
+ *
+ * Copyright (c) 2023 Aurélien Labrosse
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+#include <IGunUi.hpp>
+
+#include <Adafruit_SSD1306.h>
+#include <Fonts/FreeMonoBold18pt7b.h>
+#include <Fonts/FreeMonoOblique9pt7b.h>
+
+#define SCREEN_WIDTH 128 // OLED display width, in pixels
+#define SCREEN_HEIGHT 32 // OLED display height, in pixels
+#define OLED_RESET -1    // Reset pin # (or -1 if sharing Arduino reset pin)
+// 0x3D for 128x64, 0x3C for 128x32
+#define SCREEN_ADDRESS 0x3C
+
+static Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
+
+/**
+ * @brief UI on a SSD1306 OLED display wired over I²C bus
+ *
+ */
+class SSD1306Ui : public IGunUi {
+public:
+  SSD1306Ui() {
+
+    if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
+      for (;;)
+        ; // Don't proceed, loop forever
+    }
+  }
+  void displaySplash(uint16_t timeoutMs) override {
+    display.clearDisplay();
+    display.setTextColor(WHITE);
+    display.setTextSize(1);
+    display.setFont(&FreeMonoOblique9pt7b);
+    display.setCursor(9, 11);
+    display.println("5 in a row");
+    display.setCursor(4, 27);
+    display.println(" # # # # #");
+    display.display();
+    delay(timeoutMs);
+    display.clearDisplay();
+  }
+
+  void displayBatteryStatus(uint16_t mv, uint8_t percent) override {
+    display.setFont(NULL);
+    display.fillRect(79, 0, 59, 24, 0); // clear
+    display.setCursor(100, 2);
+    display.print(percent);
+    display.println("%");
+
+    // prepare font for next shoot count display
+    display.setFont(&FreeMonoBold18pt7b);
+  }
+  void displayChargingStatus(bool isCharging) override {
+    display.setCursor(80, 15);
+    if (isCharging) {
+      display.println("charging");
+    } else {
+      display.println("        ");
+    }
+  }
+
+  void displayShootCount(uint16_t count) override {
+    display.fillRect(11, 0, 68, 30, 0); // clear
+
+    if (count > 999)
+      count = 0;
+
+    if (count < 10) {
+      display.setCursor(15, 25);
+    } else {
+      display.setCursor(10, 25);
+    }
+    display.setFont(&FreeMonoBold18pt7b);
+    display.print(count);
+    display.display();
+  }
+};
\ No newline at end of file
diff --git a/lib/Domain/Gun/Trigger.cpp b/lib/Domain/Gun/Trigger.cpp
new file mode 100644
index 0000000..b71006c
--- /dev/null
+++ b/lib/Domain/Gun/Trigger.cpp
@@ -0,0 +1,18 @@
+/*
+ *
+ * Copyright (c) 2023 Aurélien Labrosse
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <Gun/Trigger.hpp>
diff --git a/lib/Domain/Gun/Trigger.hpp b/lib/Domain/Gun/Trigger.hpp
new file mode 100644
index 0000000..d76a102
--- /dev/null
+++ b/lib/Domain/Gun/Trigger.hpp
@@ -0,0 +1,43 @@
+/*
+ *
+ * Copyright (c) 2023 Aurélien Labrosse
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+#include <Contactor.hpp>
+
+class Trigger : public Contactor {
+public:
+  Trigger() : Contactor(), shootCycleCountdown(0) {}
+
+  // counter for ticks while firing
+  uint8_t shootCycleCountdown;
+
+  void decreaseCycleCount() {
+    if (shootCycleCountdown > 0) {
+      shootCycleCountdown--;
+    }
+  }
+
+  void onDown(long now) override {
+    if (shootCycleCountdown == 0) {
+      shootCount += 1;
+      LASER_ON();
+      OUT2_ON();
+      shootCycleCountdown = SHOOT_DURATION_CYCLE;
+    }
+    Contactor::onDown(now);
+  }
+};
diff --git a/src/GunApp.cpp b/src/GunApp.cpp
index bbb263c..7e3d12c 100644
--- a/src/GunApp.cpp
+++ b/src/GunApp.cpp
@@ -16,282 +16,22 @@
  */
 
 #include <Adafruit_SSD1306.h>
-#include <Contactor.hpp>
 #include <Fonts/FreeMonoBold18pt7b.h>
 #include <Fonts/FreeMonoOblique9pt7b.h>
 
 #include <LowPower.h>
 
-#define TRIGGER_PIN 2
-#define BUTTON2_PIN 3
+#include <Gun/Atmega328pHal.hpp>
+#include <Gun/Gun.hpp>
 
-#define LASER_PIN 10
-#define LASER_ON() PORTB |= (1 << PB2);
-#define LASER_OFF() PORTB &= ~(1 << PB2);
-
-#define OUT2_PIN 6
-#define OUT2_ON() PORTD |= (1 << PD6);
-#define OUT2_OFF() PORTD &= ~(1 << PD6);
-
-#define BATTERY_VOLTAGE_PIN A3
-#define CHARGING_STATE_PIN A2
-
-#define SHOOT_DURATION_CYCLE 5
-#define MIN_BAT_VOLTAGE 3000
-#define MAX_BAT_VOLTAGE 4120
-
-#define SCREEN_WIDTH 128 // OLED display width, in pixels
-#define SCREEN_HEIGHT 32 // OLED display height, in pixels
-#define OLED_RESET -1    // Reset pin # (or -1 if sharing Arduino reset pin)
-// 0x3D for 128x64, 0x3C for 128x32
-#define SCREEN_ADDRESS 0x3C
-
-Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
-
-volatile uint16_t hitcount;
-uint16_t previoushitcout;
-volatile uint16_t shootCount;
-
-#define BSP_TICKS_PER_SEC 100
-#define F_CPU 16000000L
-#define CYCLES_BETWEEN_UI_UPDATE 10
-
-// display API
-static void displayBatteryStatus();
-static void displayShootCount();
-
-void setup();
-static void setupHeartbeat();
-
-// counter for ticks between battery display update
-uint16_t updateBatteryDisplayCycleCount;
-
-class Trigger : public Contactor {
-public:
-  Trigger() : Contactor(), shootCycleCountdown(0) {}
-
-  // counter for ticks while firing
-  uint8_t shootCycleCountdown;
-
-  void decreaseCycleCount() {
-    if (shootCycleCountdown > 0) {
-      shootCycleCountdown--;
-    }
-  }
-
-  void onDown(long now) override {
-    if (shootCycleCountdown == 0) {
-      shootCount += 1;
-      LASER_ON();
-      OUT2_ON();
-      shootCycleCountdown = SHOOT_DURATION_CYCLE;
-    }
-    Contactor::onDown(now);
-  }
-};
-
-class Button : public Contactor {
-
-public:
-  Button() : Contactor(), calibrationMode(false) {}
-
-  bool calibrationMode;
-  void onShortPress() override { shootCount = 0; }
-  void onLongPress() override { calibrationMode = !calibrationMode; }
-};
-
-Trigger trigger;
-Button button;
-
-volatile Contactor::Event pendingTriggerEvent;
-void triggerInterruptHandler() {
-  if (bit_is_set(PIND, PD2)) {
-    pendingTriggerEvent = Contactor::Event::Released;
-  } else {
-    pendingTriggerEvent = Contactor::Event::Pressed;
-  }
-}
-
-volatile Contactor::Event pendingButtonEvent;
-void buttonInterruptHandler() {
-  if (bit_is_set(PIND, PD3)) {
-    pendingButtonEvent = Contactor::Event::Released;
-  } else {
-    pendingButtonEvent = Contactor::Event::Pressed;
-  }
-}
+Atmega328pHal hal;
+Gun gun(&hal);
 
 ISR(TIMER2_COMPA_vect) {}
 
-long now = 0;
-
-void loop(void) {
-
-  now += 10; // 10ms per loop thanks to timer2
-
-  trigger.decreaseCycleCount();
-
-  cli();
-  trigger.pendingEvent = pendingTriggerEvent;
-  button.pendingEvent = pendingButtonEvent;
-  pendingTriggerEvent = Contactor::Event::NoEvent;
-  pendingButtonEvent = Contactor::Event::NoEvent;
-  sei();
-
-  trigger.processPendingEvent(now);
-  button.processPendingEvent(now);
-
-  button.checkForLongPress(now);
-
-  if (button.calibrationMode) {
-    LASER_ON();
-    OUT2_OFF();
-
-  } else {
-    if (trigger.shootCycleCountdown == 0) {
-      LASER_OFF();
-      OUT2_OFF();
-      displayShootCount();
-    }
-
-    if (updateBatteryDisplayCycleCount > 0) {
-      updateBatteryDisplayCycleCount--;
-    }
-    if (updateBatteryDisplayCycleCount == 0) {
-      displayBatteryStatus();
-      updateBatteryDisplayCycleCount = CYCLES_BETWEEN_UI_UPDATE;
-    }
-  }
-
-  LowPower.idle(SLEEP_15MS, ADC_OFF, TIMER2_ON, TIMER1_ON, TIMER0_ON, SPI_OFF,
-                USART0_OFF, TWI_OFF);
-}
-
-static void displayShootCount() {
-  display.fillRect(11, 0, 68, 30, 0); // clear
-
-  if (shootCount > 999)
-    shootCount = 0;
-
-  if (shootCount < 10) {
-    display.setCursor(15, 25);
-  } else {
-    display.setCursor(10, 25);
-  }
-  display.print(shootCount);
-  display.display();
-}
-
-static void displayBatteryStatus() {
-
-  analogRead(BATTERY_VOLTAGE_PIN);
-  float rawBatt = analogRead(BATTERY_VOLTAGE_PIN);
-  rawBatt += analogRead(BATTERY_VOLTAGE_PIN);
-  rawBatt += analogRead(BATTERY_VOLTAGE_PIN);
-  rawBatt += analogRead(BATTERY_VOLTAGE_PIN);
-  rawBatt /= 4;
-
-  // https://rickkas7.github.io/DisplayGenerator/index.html
-
-  float battMv = (5000 / 1023.f) * rawBatt;
-  bool isCharging = (digitalRead(CHARGING_STATE_PIN) == HIGH);
-
-#if defined(SERIAL_OUTPUT)
-  Serial.print(rawBatt);
-  Serial.print(';');
-  Serial.print(battMv);
-  Serial.print(';');
-  Serial.println(isCharging ? "c" : "n");
-  delay(2);
-#endif
-
-  uint8_t battPercent = map(battMv, MIN_BAT_VOLTAGE, MAX_BAT_VOLTAGE, 0, 100);
-
-  display.setFont(NULL);
-  display.fillRect(79, 0, 59, 24, 0); // clear
-  display.setCursor(100, 2);
-  display.print(battPercent);
-  display.println("%");
-  if (isCharging) {
-    display.setCursor(80, 15);
-    display.println("charging");
-  }
-
-  // prepare font for next shoot count display
-  display.setFont(&FreeMonoBold18pt7b);
-}
-
-static void setupHeartbeat() {
-
-  // set Timer2 in CTC mode, 1/1024 prescaler, start the timer ticking...
-  TCCR2A = (1U << WGM21) | (0U << WGM20);
-  TCCR2B = (1U << CS22) | (1U << CS21) | (1U << CS20); // 1/2^10
-  ASSR &= ~(1U << AS2);
-  TIMSK2 = (1U << OCIE2A); // enable TIMER2 compare Interrupt
-  TCNT2 = 0U;
-
-  // set the output-compare register based on the desired tick frequency
-  OCR2A = (F_CPU / BSP_TICKS_PER_SEC / 1024U) - 1U;
-}
+void loop(void) { gun.loop(); }
 
 void setup(void) {
-
-#if defined(SERIAL_OUTPUT)
-  Serial.begin(115200);
-  while (!Serial) {
-  }
-#endif
-  if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
-#if defined(SERIAL_OUTPUT)
-    Serial.println(F("SSD1306 allocation failed"));
-#endif
-    for (;;)
-      ; // Don't proceed, loop forever
-  }
-
-  shootCount = 0;
-  updateBatteryDisplayCycleCount = TICKS_BETWEEN_UI_UPDATE;
-
-  pinMode(LASER_PIN, OUTPUT);
-  digitalWrite(LASER_PIN, LOW);
-
-  pinMode(OUT2_PIN, OUTPUT);
-  digitalWrite(OUT2_PIN, LOW);
-
-  pinMode(BATTERY_VOLTAGE_PIN, INPUT);
-  pinMode(CHARGING_STATE_PIN, INPUT);
-
-  pinMode(LED_BUILTIN, OUTPUT);
-  digitalWrite(LED_BUILTIN, LOW);
-
-#if defined(SERIAL_OUTPUT)
-  Serial.println("Ready!");
-#endif
-
-  display.clearDisplay();
-  display.setTextColor(WHITE);
-  display.setTextSize(1);
-  display.setFont(&FreeMonoOblique9pt7b);
-  display.setCursor(9, 11);
-  display.println("5 in a row");
-  display.setCursor(4, 27);
-  display.println(" # # # # #");
-  display.display();
-
-  delay(2000);
-
-  display.clearDisplay();
-  displayBatteryStatus();
-  displayShootCount();
-
-  pinMode(BUTTON2_PIN, INPUT_PULLUP);
-  attachInterrupt(digitalPinToInterrupt(BUTTON2_PIN), buttonInterruptHandler,
-                  CHANGE);
-
-  pinMode(TRIGGER_PIN, INPUT_PULLUP);
-  attachInterrupt(digitalPinToInterrupt(TRIGGER_PIN), triggerInterruptHandler,
-                  CHANGE);
-  cli();
-  setupHeartbeat();
-  sei();
+  hal.setupHeartbeat();
+  gun.setup();
 }
\ No newline at end of file