diff --git a/main/squeeze.h b/main/squeeze.h
--- a/main/squeeze.h
+++ b/main/squeeze.h
@@ -1,9 +1,35 @@
 #ifndef _SQUEEZE_H
 #define _SQUEEZE_H
 
+
+
+// Definitions
+#define ALPHA_FAST 0.02f
+#define ALPHA_SLOW 0.005f
+
+// Private variables
+typedef struct squeezable_
+{
+    uint32_t adc_channel;
+    float reading_fast;
+    float reading_slow;
+    float delta_last;
+    uint8_t triggered_flag;
+
+} squeezable_t;
+
+typedef enum squeezable_id_
+{
+    SQUEEZABLE_HEART = 0,
+    SQUEEZABLE_BRAIN,
+    SQUEEZABLE_MAX
+} squeezable_id_t;
+
+
 void squeeze_init(void);
-float squeeze_value(void);
-uint8_t squeeze_triggered(void);
+float squeeze_value(squeezable_id_t id);
+uint8_t squeeze_triggered(squeezable_id_t id);
+
 
 
 #endif
\ No newline at end of file