light.erl

-module(light).

-export([start/0,start/1]).

-define(TABLE, sensor).
-define(STORE, "db/sensor.db").

-define(TTY,  "/dev/ttyUSB0").
-define(LDR,  $1).
-define(INTRVL,  1000).

start() ->
    start([]).
start(Options) ->
    dets:open_file(?TABLE, [{type, set}, {file, ?STORE}]),

    TTY = proplists:get_value(tty, Options, ?TTY),
    Interval = proplists:get_value(interval, Options, ?INTRVL),
    Speed = proplists:get_value(speed, Options, 9600),
    LDR = proplists:get_value(ldr, Options, ?LDR),

    Pid = serial:start([{open, TTY}, {speed, Speed}]),
    timer:send_interval(Interval, Pid, {send, LDR}),

    loop(Pid).

loop(Pid) ->
    receive
        {data, N} when is_binary(N) ->
            %io:format("~w~n", [binary_to_integer(N)]),
            dets:insert(?TABLE, {erlang:now(), binary_to_integer(N)}),
            loop(Pid);
        Error ->
            io:format("error:~p~n", [Error])
    end.

binary_to_integer(B) when is_binary(B) ->
    list_to_integer(binary_to_list(B)).