diff --git a/.gitignore b/.gitignore
index 41cc7c8..af53804 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 docs
 .vscode
-.DS_Store
\ No newline at end of file
+.DS_Store
+build/*
\ No newline at end of file
diff --git a/README.md b/README.md
index f244487..569aeed 100644
--- a/README.md
+++ b/README.md
@@ -111,3 +111,8 @@ void UpdateDisplay() {
 }
 ```
 
+### Build for release
+
+```
+$ arduino-cli compile -v -b  arduino:avr:nano ./firmware/Gravity/Gravity.ino -e --output-dir=./build/
+```
\ No newline at end of file
diff --git a/firmware/Gravity/Gravity.ino b/firmware/Gravity/Gravity.ino
index 34de653..374ee03 100644
--- a/firmware/Gravity/Gravity.ino
+++ b/firmware/Gravity/Gravity.ino
@@ -125,13 +125,13 @@ void HandleIntClockTick(uint32_t tick) {
         int clock_index;
         switch (app.selected_pulse) {
             case Clock::PULSE_PPQN_24:
-                clock_index = 0;
+                clock_index = PULSE_PPQN_24_CLOCK_MOD_INDEX;
                 break;
             case Clock::PULSE_PPQN_4:
-                clock_index = 4;
+                clock_index = PULSE_PPQN_4_CLOCK_MOD_INDEX;
                 break;
             case Clock::PULSE_PPQN_1:
-                clock_index = 7;
+                clock_index = PULSE_PPQN_1_CLOCK_MOD_INDEX;
                 break;
         }
 
diff --git a/firmware/Gravity/channel.h b/firmware/Gravity/channel.h
index 6f46b28..8036781 100644
--- a/firmware/Gravity/channel.h
+++ b/firmware/Gravity/channel.h
@@ -53,6 +53,10 @@ static const int CLOCK_MOD_PULSES[MOD_CHOICE_SIZE] PROGMEM = {
 
 static const byte DEFAULT_CLOCK_MOD_INDEX = 8;  // x1 or 96 PPQN.
 
+static const byte PULSE_PPQN_24_CLOCK_MOD_INDEX = 0;
+static const byte PULSE_PPQN_4_CLOCK_MOD_INDEX = 4;
+static const byte PULSE_PPQN_1_CLOCK_MOD_INDEX = 8;
+
 class Channel {
    public:
     Channel() {