Merge pull request #269 from ftruzzi/master

New module: HDC1000 temperature and humidity sensor.

lua_modules/hdc1000/HDC1000-example.lua

@@ -0,0 +1,12 @@
+HDC1000 = require("HDC1000")
+
+sda = 1
+scl = 2
+
+HDC1000.init(sda, scl)
+HDC1000.config() -- default values are used if called with no arguments. prototype is config(address, resolution, heater)
+
+print(string.format("Temperature: %.2f °C\nHumidity: %.2f %%", HDC1000.getTemp(), HDC1000.getHumi()))
+
+HDC1000 = nil
+package.loaded["HDC1000"]=nil

lua_modules/hdc1000/HDC1000.lua

@@ -0,0 +1,99 @@
+-------------------------------------------------------
+
+-- This library was written for the Texas Instruments 
+-- HDC1000 temperature and humidity sensor. 
+-- It should work for the HDC1008 too.
+-- Written by Francesco Truzzi (francesco@truzzi.me)
+-- Released under GNU GPL v2.0 license.
+
+-------------------------------------------------------
+
+-------------- NON-DEFAULT CONFIG VALUES --------------
+------------- config() optional arguments -------------
+
+--	HDC1000_HEAT_OFF			0x00	(heater)
+--	HDC1000_TEMP_11BIT			0x40	(resolution)
+-- 	HDC1000_HUMI_11BIT			0x01 	(resolution)
+--	HDC1000_HUMI_8BIT			0x20 	(resolution)
+
+-------------------------------------------------------
+
+local modname = ...
+local M = {}
+_G[modname] = M
+
+local id = 0
+local i2c = i2c
+local delay = 20000
+
+local HDC1000_ADDR = 0x40
+
+local HDC1000_TEMP = 0x00
+local HDC1000_HUMI = 0x01
+local HDC1000_CONFIG = 0x02
+
+local HDC1000_HEAT_ON = 0x20
+local HDC1000_TEMP_HUMI_14BIT = 0x00
+
+-- reads 16bits from the sensor
+local function read16()
+	i2c.start(id)
+	i2c.address(id, HDC1000_ADDR, i2c.RECEIVER)
+	data_temp = i2c.read(0, 2)
+	i2c.stop(id)
+	data = bit.lshift(string.byte(data_temp, 1, 1), 8) + string.byte(data_temp, 2, 2)
+	return data
+end
+
+-- sets the register to read next
+local function setReadRegister(register)
+	i2c.start(id)
+	i2c.address(id, HDC1000_ADDR, i2c.TRANSMITTER)
+	i2c.write(id, register)
+	i2c.stop(id)
+end
+
+-- writes the 2 configuration bytes
+local function writeConfig(config)
+	i2c.start(id)
+	i2c.address(id, HDC1000_ADDR, i2c.TRANSMITTER)
+	i2c.write(id, HDC1000_CONFIG, config, 0x00)
+	i2c.stop(id)
+end
+
+-- returns true if battery voltage is < 2.7V, false otherwise
+function M.batteryDead()
+	setReadRegister(HDC1000_CONFIG)
+	return(bit.isset(read16(), 11))
+
+end
+
+-- initalize i2c
+function M.init(sda, scl)
+	i2c.setup(id, sda, scl, i2c.SLOW)
+end
+
+function M.config(addr, resolution, heater)
+	-- default values are set if the function is called with no arguments
+	HDC1000_ADDR = addr or HDC1000_ADDR
+	resolution = resolution or HDC1000_TEMP_HUMI_14BIT
+	heater = heater or HDC1000_HEAT_ON
+	writeConfig(bit.bor(resolution, heater))
+end
+
+-- outputs temperature in Celsius degrees
+function M.getHumi()
+	setReadRegister(HDC1000_HUMI)
+	tmr.delay(delay)
+	return(read16()/65535.0*100)
+end
+
+-- outputs humidity in %RH
+function M.getTemp()
+	setReadRegister(HDC1000_TEMP)
+	tmr.delay(delay)
+	return(read16()/65535.0*165-40)
+end
+
+return M
+

lua_modules/hdc1000/README.md

@@ -0,0 +1,39 @@
+HDC1000 NodeMCU module
+=======================
+
+Here's my NodeMCU module for the TI HDC1000 temperature and humidity sensor. It should work with the HDC1008 too but I haven't tested it.
+
+### Setup your sensor:
+First, require it:
+
+`HDC1000 = require("HDC1000")`
+
+Then, initialize it:
+
+`HDC1000.init(sda, scl)`
+
+Configure it:
+
+`HDC1000.config()`
+
+Default options set the address to 0x40 and enable both temperature and humidity readings at 14-bit resolution, with the integrated heater on. You can change them by initializing your sensor like this:
+
+`HDC1000.config(address, resolution, heater);`
+
+"resolution" can be set to 14 bits for both temperature and humidity (0x00 - default) 11 bits for temperature (0x40), 11 bits for humidity (0x01), 8 bits for humidity (0x20)
+"heater" can be set to ON (0x20 - default) or OFF (0x00)
+
+### Read some values
+You can read temperature and humidity by using the following commands:
+
+`temperature = HDC1000.getTemp()` in Celsius degrees.
+
+`humidity = HDC1000.getHumi()` in %
+
+### Check your battery
+
+The following code returns true if the battery voltage is <2.8V, false otherwise.
+
+`isDead = HDC1000.batteryDead();`
+
+Happy making! Also, check out my Breakout Board and Arduino library for this chip: http://b.truzzi.me/hdc1000-temperature-and-humidity-sensor-breakout-with-arduino-library/.