diff --git a/core/lib/sensors.c b/core/lib/sensors.c
index f6392506a..54bb204cf 100644
--- a/core/lib/sensors.c
+++ b/core/lib/sensors.c
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * @(#)$Id: sensors.c,v 1.4 2010/01/14 13:55:21 nifi Exp $
+ * @(#)$Id: sensors.c,v 1.5 2010/01/14 20:04:38 nifi Exp $
  */
 /* exeperimental code, will be renamed to sensors.c when done */
 
@@ -83,7 +83,7 @@ sensors_changed(const struct sensors_sensor *s)
 }
 /*---------------------------------------------------------------------------*/
 struct sensors_sensor *
-sensors_find(char *prefix)
+sensors_find(const char *prefix)
 {
   int i;
   unsigned short len;
diff --git a/core/lib/sensors.h b/core/lib/sensors.h
index def881a5b..ef96cec75 100644
--- a/core/lib/sensors.h
+++ b/core/lib/sensors.h
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * @(#)$Id: sensors.h,v 1.6 2010/01/14 15:33:27 joxe Exp $
+ * @(#)$Id: sensors.h,v 1.7 2010/01/14 20:04:38 nifi Exp $
  */
 
 #ifndef __SENSORS_H__
@@ -60,7 +60,7 @@ struct sensors_sensor {
   int          (* status)    (int type);
 };
 
-struct sensors_sensor *sensors_find(char *type);
+struct sensors_sensor *sensors_find(const char *type);
 struct sensors_sensor *sensors_next(const struct sensors_sensor *s);
 struct sensors_sensor *sensors_first(void);