From 86bf15760352a5f29e07e4e3d0d2b0e48904f405 Mon Sep 17 00:00:00 2001
From: Fraser Savage <fraser_sav@yahoo.co.uk>
Date: Mon, 24 Oct 2016 19:09:36 +0100
Subject: [PATCH] Adds humidity reading to the climate module

---
 climate-si7020/src/lib.rs  | 12 +++++++++++-
 climate-si7020/src/main.rs |  2 +-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/climate-si7020/src/lib.rs b/climate-si7020/src/lib.rs
index d30829d..aa152df 100644
--- a/climate-si7020/src/lib.rs
+++ b/climate-si7020/src/lib.rs
@@ -11,7 +11,7 @@ use std::time::Duration;
 #[derive(Copy, Clone)]
 enum Command {
     TempHold = 0xE3,
-
+    RHHold = 0xE5,
     ReadId1 = 0xFA,
     ReadId2 = 0x0F,
     ReadId3 = 0xFC,
@@ -83,4 +83,14 @@ impl<'a> Climate<'a> {
 
         Ok(temp)
     }
+
+    pub fn read_humidity(&mut self) -> io::Result<f64> {
+        let mut buf = [0; 2];
+        try!(self.read(&[Command::RHHold], &mut buf));
+
+        let raw_humidity = ((buf[0] as u16) << 8) + (buf[1] as u16);
+        let humidity = ((raw_humidity as f64) * HUMIDITY_SLOPE) - HUMIDITY_OFFSET;
+
+        Ok(humidity)
+    }
 }
diff --git a/climate-si7020/src/main.rs b/climate-si7020/src/main.rs
index 4d5f085..d3d0395 100644
--- a/climate-si7020/src/main.rs
+++ b/climate-si7020/src/main.rs
@@ -17,7 +17,7 @@ fn main() {
     println!("Reading climate sensor... (Press CTRL + C to stop)");
     loop {
         println!("Temperature (Fahrenheit): {:?}", climate.read_temperature());
-
+        println!("Humidity: {:?}", climate.read_humidity());
         // Continue the loop after sleeping for 100ms.
         sleep(Duration::from_millis(100));
     }