--- a/rust/src/types.rs	Tue Dec 27 00:51:28 2016 +0800
+++ b/rust/src/types.rs	Wed Jan 04 17:18:44 2017 +0800
@@ -1,3 +1,6 @@
+use std::collections::HashMap;
+use std::time::Duration;
+
 #[derive(RustcDecodable, RustcEncodable, Debug, Clone)]
 pub struct Params {
     pub fridge_setpoint: f32,
@@ -41,42 +44,40 @@
 }
 
 #[derive(Debug)]
-pub struct Reading {
-    name: String,
-    value: Option<f32>,
-}
-
-impl Reading {
-    pub fn new(name: String, value: f32) -> Reading {
-        Reading { name: name, value: Some(value) }
-    }
-    pub fn new_none(name: String) -> Reading {
-        Reading { name: name, value: None }
-    }
-}
-
-#[derive(Debug)]
 pub struct Readings {
-    temps: Vec<Vec<Reading>>,
+    temps: HashMap<String, Option<f32>>,
 }
 
 impl Readings {
     pub fn new() -> Readings {
         Readings {
-            temps: Vec::new(),
+            temps: HashMap::new(),
         }
     }
 
-    pub fn push(&mut self, vals: Vec<Reading>) {
-        self.temps.push(vals);
+    pub fn add(&mut self, name: &str, v: Option<f32>) {
+        if let Some(prev) = self.temps.insert(name.to_string(), v) {
+            warn!("Replaced existing reading '{}' {:?} -> {:?}",
+                name, prev, v);
+        }
     }
 
     pub fn fridge(&self) -> Option<f32> {
-        unimplemented!();
+        if let Some(t) = self.temps.get("fridge") {
+            t.clone()
+        } else {
+            warn!("No fridge reading was added");
+            None
+        }
     }
 
     pub fn wort(&self) -> Option<f32> {
-        unimplemented!();
+        if let Some(t) = self.temps.get("wort") {
+            t.clone()
+        } else {
+            warn!("No wort reading was added");
+            None
+        }
     }
 }