1 files changed, 7 insertions, 4 deletions
diff --git a/include/brain/sensor.h b/include/brain/sensor.h
index 06b96d0..b33080b 100644
--- a/include/brain/sensor.h
+++ b/include/brain/sensor.h
@@ -4,10 +4,13 @@
 
 class Sensor: public NeuralNode
 {
-private:
-    double _activation;
-    
 public:
+    Sensor(int id);
+    virtual ~Sensor() {}
+    
     void setActivation(double activation) { _activation = activation; }
-    virtual double activation() { return _activation; }
+    virtual double activation() const { return _activation; }
+    
+private:
+    double _activation;
 };