nodemcu-firmware/modules/ds18b20.EN.md

#DS18B20 Module ##Require

ds18b20 = require("ds18b20")

##Constant C, F, K

##setup() ####Description Setting the pin of DS18B20.

####Syntax setup(pin)

####Parameters pin: 1~10, IO index. If parameter is nil, it will use pin 9(GPIO2) automatically.

####Returns nil

####Example

ds18b20 = require("ds18b20")
ds18b20.setup(9)

####See also -

addrs()

####Description Return a table contain all of the addresses of DS18B20 on one-wire. If the setup(pin) function not executed, the pin 9(GPIO2) will be initialized as one-wire mode automatically.

####Syntax addrs()

####Parameters nil ####Returns addrs: A table contain all of the addresses of DS18B20 on one-wire. Every address is a string. If failed, it will be nil.

####Example

ds18b20 = require("ds18b20")
ds18b20.setup(9)
addrs = ds18b20.addrs()
if (addrs ~= nil) then
  print("Total DS18B20 sensors: "..table.getn(addrs))
end

####See also -

readNumber()

####Description Read the value of temperature. If the setup(pin) function not executed, the pin 9(GPIO2) will be initialized as one-wire mode automatically.

####Syntax readNumber(addr, unit)

####Parameters addr: string, the address of DS18B20. It will select the first address which be found when this parameter is nil.
unit: integer, unit conversion. Only Constant is acceptable, such as C(Celsius),F(Fahrenheit) and K(Kelvin). If this parameter is nil, the constant C(Celsius) will be selected automatically.

####Returns t1: integer. The integer part of the temperature. If it read fails, return nil.
t2: integer. The fractional part of the temperature. If it read fails, return nil.

####Example

t=require("ds18b20")
t.setup(9)
addrs=t.addrs()
-- Total DS18B20 numbers, assume it is 2
print(table.getn(addrs))
-- The first DS18B20
print(t.readNumber(addrs[1],t.C))
print(t.readNumber(addrs[1],t.F))
print(t.readNumber(addrs[1],t.K))
-- The second DS18B20
print(t.readNumber(addrs[2],t.C))
print(t.readNumber(addrs[2],t.F))
print(t.readNumber(addrs[2],t.K))
-- Just read
print(t.readNumber())
-- Just read as fahrenheit
print(t.readNumber(nil,t.F))
-- Read as values
t1, t2 = t.readNumber()

####See also -

read()

####Description Read the string of temperature. If the setup(pin) function not executed, the pin 9(GPIO2) will be initialized as one-wire mode automatically.

####Syntax read(addr, unit)

####Parameters addr: string, the address of DS18B20. It will select the first address which be found when this parameter is nil.
unit: integer, unit conversion. Only Constant is acceptable, such as C(Celsius),F(Fahrenheit) and K(Kelvin). If this parameter is nil, the constant C(Celsius) will be selected automatically.

####Returns t: string. The string of the temperature. If it read fails, return nil.

####Example

t=require("ds18b20")
t.setup(9)
addrs=t.addrs()
-- Total DS18B20 numbers, assume it is 2
print(table.getn(addrs))
-- The first DS18B20
print(t.read(addrs[1],t.C))
print(t.read(addrs[1],t.F))
print(t.read(addrs[1],t.K))
-- The second DS18B20
print(t.read(addrs[2],t.C))
print(t.read(addrs[2],t.F))
print(t.read(addrs[2],t.K))
-- Just read
print(t.read())
-- Just read as centigrade
print(t.read(nil,t.C))

####See also -