From 1de19b208a419425af6129970211863c20ce6295 Mon Sep 17 00:00:00 2001
From: ztimson <zaktimson@gmail.com>
Date: Wed, 30 Oct 2024 11:03:30 -0400
Subject: [PATCH] Temp fix

---
 src/bme.js    | 21 ---------------------
 src/bme280.js | 12 +++++++++++-
 2 files changed, 11 insertions(+), 22 deletions(-)
 delete mode 100644 src/bme.js

diff --git a/src/bme.js b/src/bme.js
deleted file mode 100644
index d22fc6a..0000000
--- a/src/bme.js
+++ /dev/null
@@ -1,21 +0,0 @@
-import i2c from 'i2c-bus';
-
-export async function bme(address = 0x76) {
-    const i2cBus = await i2c.openPromisified(1);
-    const data = await Promise.all([
-        i2cBus.readByte(address, 0xFA),
-        i2cBus.readByte(address, 0xFB),
-        i2cBus.readByte(address, 0xFC),
-        i2cBus.readByte(address, 0xF7),
-        i2cBus.readByte(address, 0xF8),
-        i2cBus.readByte(address, 0xF9),
-        i2cBus.readByte(address, 0xFD),
-        i2cBus.readByte(address, 0xFE),
-    ]);
-    return {
-        temperature: (((data[0] << 12) | (data[1] << 4) | (data[2] >> 4)) / 16384.0 - 5120.0) / 100,
-        pressure: ((data[3] << 12) | (data[4] << 4) | (data[5] >> 4))  / 25600,
-        humidity: ((data[6] << 8) | data[7]) / 1024.0,
-    };
-}
-console.log(await bme());
diff --git a/src/bme280.js b/src/bme280.js
index dc680aa..d71df90 100644
--- a/src/bme280.js
+++ b/src/bme280.js
@@ -12,8 +12,18 @@ export async function bme(address = 0x76) {
         i2cBus.readByte(address, 0xFD),
         i2cBus.readByte(address, 0xFE),
     ]);
+
+    const T1 = 27504;
+    const T2 = 26435;
+    const T3 = -1000;
+
+    const rawTemp = (data[0] << 12) | (data[1] << 4) | (data[2] >> 4);
+    let var1 = (((rawTemp >> 3) - (T1 << 1)) * T2) / 2048;
+    let var2 = (((((rawTemp >> 4) - T1) * ((rawTemp >> 4) - T1)) >> 12) * T3) / 16384;
+    let temp = (var1 + var2) / 5120.0;
+
     return {
-        temperature: (((data[0] << 12) | (data[1] << 4) | (data[2] >> 4)) / 16384.0 - 5120.0) / 100,
+        temperature: temp,
         pressure: ((data[3] << 12) | (data[4] << 4) | (data[5] >> 4)) / 25600,
         humidity: ((data[6] << 8) | data[7]) / 1024.0,
     };