diff --git a/src/Things/Motor.cs b/src/Things/Motor.cs
index a41cc9a..23dbbd3 100644
--- a/src/Things/Motor.cs
+++ b/src/Things/Motor.cs
@@ -40,7 +40,7 @@ namespace RoboidControl {
             return data;
         }
         public override void ProcessBinary(byte[] data) {
-            this.targetSpeed = (float)data[0] / 127;
+            this.targetSpeed = (float)(sbyte)data[0] / 127;
         }
     }