diff --git a/Inc/config.h b/Inc/config.h
index fb9e198..20be07f 100644
--- a/Inc/config.h
+++ b/Inc/config.h
@@ -8,10 +8,10 @@
 #if !defined(PLATFORMIO)
   //#define VARIANT_ADC         // Variant for control via ADC input
   //#define VARIANT_USART3      // Variant for Serial control via USART3 input
-  //#define VARIANT_HOVERCAR    // Variant for HOVERCAR build
-  //#define VARIANT_TRANSPOTTER // Variant for TRANSPOTTER build https://github.com/NiklasFauth/hoverboard-firmware-hack/wiki/Build-Instruction:-TranspOtter https://hackaday.io/project/161891-transpotter-ng
   //#define VARIANT_NUNCHUCK    // Variant for Nunchuck controlled vehicle build
   //#define VARIANT_PPM         // Variant for RC-Remote with PPM-Sum Signal
+  //#define VARIANT_HOVERCAR    // Variant for HOVERCAR build
+  //#define VARIANT_TRANSPOTTER // Variant for TRANSPOTTER build https://github.com/NiklasFauth/hoverboard-firmware-hack/wiki/Build-Instruction:-TranspOtter https://hackaday.io/project/161891-transpotter-ng
 #endif
 
 // For any particular needs, feel free to change this file according to your needs.
diff --git a/Inc/defines.h b/Inc/defines.h
index 51462c6..ec5f6bc 100644
--- a/Inc/defines.h
+++ b/Inc/defines.h
@@ -174,8 +174,10 @@ void mixerFcn(int16_t rtu_speed, int16_t rtu_steer, int16_t *rty_speedR, int16_t
 void rateLimiter16(int16_t u, int16_t rate, int16_t *y);
 void multipleTapDet(int16_t u, uint32_t timeNow, MultipleTap *x);
 
-// Define I2C and Nunchuck functions
+// Define I2C, Nunchuck, PPM functions
 void I2C_Init(void);
 void Nunchuck_Init(void);
 void Nunchuck_Read(void);
-uint8_t Nunchuck_Ping(void);
\ No newline at end of file
+uint8_t Nunchuck_Ping(void);
+void PPM_Init(void);
+void PPM_ISR_Callback(void);
\ No newline at end of file
diff --git a/Src/main.c b/Src/main.c
index 60d09da..6d632b5 100644
--- a/Src/main.c
+++ b/Src/main.c
@@ -71,7 +71,8 @@ extern volatile adc_buf_t adc_buffer;
   LCD_PCF8574_HandleTypeDef lcd;
 #endif
 extern I2C_HandleTypeDef hi2c2;
-#ifndef VARIANT_TRANSPOTTER
+#if defined(CONTROL_SERIAL_USART2) || defined(FEEDBACK_SERIAL_USART2) || defined(DEBUG_SERIAL_USART2) \
+ || defined(CONTROL_SERIAL_USART3) || defined(FEEDBACK_SERIAL_USART3) || defined(DEBUG_SERIAL_USART3) 
   extern UART_HandleTypeDef huart2;
   extern UART_HandleTypeDef huart3;
   static UART_HandleTypeDef huart;
@@ -454,7 +455,8 @@ int main(void) {
       cmd1 = CLAMP((ppm_captured_value[0] - INPUT_MID) * 2, INPUT_MIN, INPUT_MAX);
       cmd2 = CLAMP((ppm_captured_value[1] - INPUT_MID) * 2, INPUT_MIN, INPUT_MAX);
       button1 = ppm_captured_value[5] > INPUT_MID;
-      float scale = ppm_captured_value[2] / 1000.0f;
+      button2 = 0;
+      // float scale = ppm_captured_value[2] / 1000.0f;     // not used for now, uncomment if needed
     #endif
 
     #ifdef CONTROL_ADC
diff --git a/Src/stm32f1xx_it.c b/Src/stm32f1xx_it.c
index 8ca24ee..9de1ee7 100644
--- a/Src/stm32f1xx_it.c
+++ b/Src/stm32f1xx_it.c
@@ -34,6 +34,7 @@
 #include "stm32f1xx_hal.h"
 #include "stm32f1xx.h"
 #include "stm32f1xx_it.h"
+#include "defines.h"
 #include "config.h"
 
 extern DMA_HandleTypeDef hdma_i2c2_rx;
diff --git a/platformio.ini b/platformio.ini
index fd04d77..7e2efea 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -11,10 +11,12 @@ src_dir     = Src
 ;
 ;default_envs = VARIANT_ADC         ; Variant for control via ADC input
 ;default_envs = VARIANT_USART3      ; Variant for Serial control via USART3 input
-;default_envs = VARIANT_HOVERCAR    ; Variant for HOVERCAR build
-;default_envs = VARIANT_TRANSPOTTER ; Variant for TRANSPOTTER build https://github.com/NiklasFauth/hoverboard-firmware-hack/wiki/Build-Instruction:-TranspOtter https://hackaday.io/project/161891-transpotter-ng
 ;default_envs = VARIANT_NUNCHUCK    ; Variant for Nunchuck controlled vehicle build
 ;default_envs = VARIANT_PPM         ; Variant for RC-Remotes with PPM-Sum signal
+;default_envs = VARIANT_HOVERCAR    ; Variant for HOVERCAR build
+;default_envs = VARIANT_TRANSPOTTER ; Variant for TRANSPOTTER build https://github.com/NiklasFauth/hoverboard-firmware-hack/wiki/Build-Instruction:-TranspOtter https://hackaday.io/project/161891-transpotter-ng
+;================================================================
+
 ;================================================================
 
 [env:VARIANT_ADC]
@@ -40,6 +42,8 @@ build_flags =
     -D VARIANT_ADC
     -D PALTFORMIO
 
+;================================================================
+
 [env:VARIANT_USART3]
 platform        = ststm32
 framework       = stm32cube
@@ -63,17 +67,15 @@ build_flags =
     -D VARIANT_USART3
     -D PALTFORMIO
 
-[env:VARIANT_HOVERCAR]
+;================================================================
+
+[env:VARIANT_NUNCHUCK]
 platform        = ststm32
 framework       = stm32cube
 board           = genericSTM32F103RC
 debug_tool      = stlink
 upload_protocol = stlink
 
-; Serial Port settings (make sure the COM port is correct)
-monitor_port    = COM5
-monitor_speed   = 38400
-
 build_flags =
     -I${PROJECT_DIR}/inc/
     -DUSE_HAL_DRIVER
@@ -83,10 +85,12 @@ build_flags =
     -Wl,-lm
     -g -ggdb        ; to generate correctly the 'firmware.elf' for STM STUDIO vizualization
 #    -Wl,-lnosys
-    -D VARIANT_HOVERCAR
+    -D VARIANT_NUNCHUCK
     -D PALTFORMIO
 
-[env:VARIANT_TRANSPOTTER]
+;================================================================
+
+[env:VARIANT_PPM]
 platform        = ststm32
 framework       = stm32cube
 board           = genericSTM32F103RC
@@ -102,16 +106,22 @@ build_flags =
     -Wl,-lm
     -g -ggdb        ; to generate correctly the 'firmware.elf' for STM STUDIO vizualization
 #    -Wl,-lnosys
-    -D VARIANT_TRANSPOTTER
+    -D VARIANT_PPM
     -D PALTFORMIO
 
-[env:VARIANT_NUNCHUCK]
+;================================================================
+
+[env:VARIANT_HOVERCAR]
 platform        = ststm32
 framework       = stm32cube
 board           = genericSTM32F103RC
 debug_tool      = stlink
 upload_protocol = stlink
 
+; Serial Port settings (make sure the COM port is correct)
+monitor_port    = COM5
+monitor_speed   = 38400
+
 build_flags =
     -I${PROJECT_DIR}/inc/
     -DUSE_HAL_DRIVER
@@ -121,10 +131,12 @@ build_flags =
     -Wl,-lm
     -g -ggdb        ; to generate correctly the 'firmware.elf' for STM STUDIO vizualization
 #    -Wl,-lnosys
-    -D VARIANT_NUNCHUCK
+    -D VARIANT_HOVERCAR
     -D PALTFORMIO
 
-[env:VARIANT_PPM]
+;================================================================
+
+[env:VARIANT_TRANSPOTTER]
 platform        = ststm32
 framework       = stm32cube
 board           = genericSTM32F103RC
@@ -140,5 +152,7 @@ build_flags =
     -Wl,-lm
     -g -ggdb        ; to generate correctly the 'firmware.elf' for STM STUDIO vizualization
 #    -Wl,-lnosys
-    -D VARIANT_PPM
-    -D PALTFORMIO
\ No newline at end of file
+    -D VARIANT_TRANSPOTTER
+    -D PALTFORMIO
+    
+;================================================================
\ No newline at end of file