diff --git a/src/nlgpio16/nlgpio16.h b/src/nlgpio16/nlgpio16.h
index 8ad817f7..4070690e 100644
--- a/src/nlgpio16/nlgpio16.h
+++ b/src/nlgpio16/nlgpio16.h
@@ -38,6 +38,12 @@
 
 #define NLGPIO16_DEFAULT_UART_DEV "/dev/ttyACM0"
 
+// ADC analog ref voltage is 3.3v
+#define ADC_AREF 3.3
+
+// 10-bit precision (0-1023)
+#define ADC_PRECISION 10
+
 namespace upm {
     /**
      * @brief NLGPIO16 module
@@ -82,11 +88,6 @@ namespace upm {
   class NLGPIO16 {
   public:
 
-    // ADC analog ref voltage is 3.3v
-    static const float ADC_AREF = 3.3;
-    // 10-bit precision (0-1023)
-    static const int ADC_PRECISION = 10;
-
     /**
      * NLGPIO16 object constructor
      *