diff --git a/src/registries.rs b/src/registries.rs
index e5d218c..bf7d371 100644
--- a/src/registries.rs
+++ b/src/registries.rs
@@ -1,4 +1,5 @@
 mod actuators;
+mod sensors;
 
 pub use actuators::{Actuator, ActBox};
 
diff --git a/src/registries/sensors.rs b/src/registries/sensors.rs
index 3508b2e..25c41ee 100644
--- a/src/registries/sensors.rs
+++ b/src/registries/sensors.rs
@@ -1,9 +1,19 @@
+use std::pin::Pin;
+use futures::task::{Context, Poll};
 use futures::{Future, Stream};
+use futures::future::BoxFuture;
+
+use std::sync::Arc;
+use smol::lock::RwLock;
+use std::collections::HashMap;
 
 pub struct Sensors {
-    
+    inner: Arc<RwLock<Inner>>,
 }
 
+pub type SensBox<'a> = Box<dyn Sensor<'a>>;
+type Inner = HashMap<String, SensBox<'static>>;
+
 
 // Implementing Sensors.
 //
@@ -11,6 +21,45 @@ pub struct Sensors {
 // machine update signal to actor doing thing being another, a Sensor implementation would send a
 // Stream of futures - each future being an atomic Machine update.
 #[async_trait]
-pub trait Sensor: Stream<Item = Box<dyn Future<Output = ()>>> {
-    async fn setup() -> Self;
+/// BFFH Sensor
+///
+/// A sensor is anything that can forward an intent of an user to do something to bffh.
+/// This may be a card reader connected to a machine, a website allowing users to select a machine
+/// they want to use or something like QRHello
+pub trait Sensor<'a>: Stream<Item = BoxFuture<'a, ()>> {
+    /// Setup the Sensor.
+    ///
+    /// After this async function completes the Stream implementation should be able to generate
+    /// futures when polled.
+    /// Implementations can rely on this function being polled to completeion before the stream
+    /// is polled.
+    async fn setup(&mut self);
+
+    /// Shutdown the sensor gracefully
+    ///
+    /// Implementations can rely on that the stream will not be polled after this function has been
+    /// called.
+    async fn shutdown(&mut self);
+}
+
+struct Dummy<'a> {
+    phantom: &'a std::marker::PhantomData<()>,
+}
+#[async_trait]
+impl<'a> Sensor<'a> for Dummy<'a> {
+    async fn setup(&mut self) {
+        return;
+    }
+
+    async fn shutdown(&mut self) {
+        return;
+    }
+}
+
+impl<'a> Stream for Dummy<'a> {
+    type Item = BoxFuture<'a, ()>;
+
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
+        todo!()
+    }
 }