diff --git a/Engine/src/live/Entity.ts b/Engine/src/live/Entity.ts
index 0950f63..8b0345c 100644
--- a/Engine/src/live/Entity.ts
+++ b/Engine/src/live/Entity.ts
@@ -3,6 +3,17 @@ import { SpriteInstance } from '../shared/sprites'
 import { WorldContext } from './World'
 import { Zone } from './Zone'
 
+export class Sensor {
+  entity: Entity
+  fixture: planck.Fixture
+  type: 'short'|'long'
+  constructor(entity: Entity, fixture: planck.Fixture, type: 'short'|'long') {
+    this.entity = entity
+    this.fixture = fixture
+    this.type = type
+  }
+}
+
 export class Entity {
   sprite: SpriteInstance
   body?: planck.Body