-- Serial port must be configured before opening the file
-- stty -F /dev/ttyACM0 9600

local deviceNum = 1
local serialPort = "/dev/ttyACM0"

JSON = (loadfile "/home/pi/bin/domoticz/scripts/lua/JSON.lua")() -- one-time load of the routines

commandArray = {}

-- Open seria port in read and write
wserial=io.open(serialPort, "w")
rserial=io.open(serialPort, "r")

-- Because Arduino auto-reset when a serial line is open, wait the end of reset before doing anything
os.execute("sleep 2")

-- First send a command to read the temperature.
rserial:flush()
wserial:write("r")
wserial:flush()
rserial:read()
rserial:flush()

-- Do it another time in order to ensure we have a full frame
wserial:write("r")
wserial:flush()
read_value = rserial:read()

-- Ask a new read until a signal has been received from the sensor. It should be available within next 30 seconds with this sensor.
local nbTries = 0;
local json_value = JSON:decode(read_value)
while json_value.channel==0 and nbTries < 16 do
	nbTries = nbTries + 1
	os.execute("sleep 2")
	wserial:write("r")
	wserial:flush()
	read_value = rserial:read()
	json_value = JSON:decode(read_value)	
end

-- Update the sensor value with the new temperature if a temperature has been read
if json_value.channel==1 then
	commandArray['UpdateDevice']=deviceNum..'|0|'..json_value.temp/10
	-- print("[DEBUG] Temperature: "..json_value.temp)
end

return commandArray