From ee6a1033c293f3d3b327568fe9554d4651c4c964 Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Wed, 25 May 2022 21:44:57 +0200
Subject: initial commit

---
 mh-z19.lua | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 mh-z19.lua

(limited to 'mh-z19.lua')

diff --git a/mh-z19.lua b/mh-z19.lua
new file mode 100644
index 0000000..fe269b8
--- /dev/null
+++ b/mh-z19.lua
@@ -0,0 +1,28 @@
+local mhz19 = {}
+
+local c_read = string.char(0xff, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x79)
+
+mhz19.co2 = nil
+mhz19.temp = nil
+mhz19.tt = nil
+mhz19.ss = nil
+mhz19.uu = nil
+
+function mhz19.query()
+	return c_read
+end
+
+function mhz19.parse_frame(data)
+	local head, cmd, co2h, co2l, temp, tt, ss, uh, ul = struct.unpack("BBBBBBBBB", data)
+	if head ~= 0xff or cmd ~= 0x86 then
+		return false
+	end
+	mhz19.co2 = co2h * 256 + co2l
+	mhz19.temp = temp - 40
+	mhz19.tt = tt
+	mhz19.ss = ss
+	mhz19.uu = uh * 256 + ul
+	return true
+end
+
+return mhz19
-- 
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