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| -module(simple_temp). | |
| -export([start/0, get_temp/0]). | |
| init() -> | |
| gpio_sup:start_link([{18, output}, {23, output}]). | |
| set(Val) -> | |
| gpio:write(18, lists:nth(1, Val)), | |
| gpio:write(23, lists:nth(2, Val)). | |
| blink() -> | |
| set([1,1]), | |
| io:format("LED on~n"), | |
| timer:sleep(1000), | |
| set([0,0]), | |
| io:format("LED off~n"), | |
| timer:sleep(1000). | |
| %% Temperature reading inspired from https://github.com/mokele/onewire_therm | |
| -record(therm, { | |
| message, | |
| crc, | |
| temperature, | |
| timestamp | |
| }). | |
| read(Binary) when is_binary(Binary) -> | |
| read(Binary, #therm{ | |
| timestamp = erlang:now() | |
| }). | |
| read(<<A1:16,_,A2:16,_,A3:16,_,A4:16,_,A5:16,_,A6:16,_,A7:16,_,A8:16,_,CRC:16,_,$:,_,"crc=",CRC:16,_,"YES",Rest0/binary>>, | |
| #therm{ | |
| message = undefined | |
| } = OneWire) -> | |
| [_, Rest] = to_nl(Rest0), | |
| read(Rest, OneWire#therm{ | |
| message = <<A1:16,A2:16,A3:16,A4:16,A5:16,A6:16,A7:16,A8:16>>, | |
| crc = <<CRC:16>> | |
| }); | |
| read(<<A1:16,_,A2:16,_,A3:16,_,A4:16,_,A5:16,_,A6:16,_,A7:16,_,A8:16,_,CRC:16," t=",Rest/binary>>, | |
| #therm{ | |
| message = <<A1:16,A2:16,A3:16,A4:16,A5:16,A6:16,A7:16,A8:16>>, | |
| crc = <<CRC:16>> | |
| } = OneWire) -> | |
| [TemperatureBinary|_] = to_nl(Rest), | |
| read(Rest, OneWire#therm{ | |
| temperature = list_to_integer(binary_to_list(TemperatureBinary)) / 1000 | |
| }); | |
| read(_, #therm{ | |
| message = Message, | |
| crc = CRC, | |
| temperature = Temperature | |
| }) when Message =:= undefined; CRC =:= undefined; Temperature =:= undefined -> | |
| {error, temperature_not_found}; | |
| read(_, #therm{ | |
| temperature = Temperature, | |
| timestamp = Timestamp | |
| }) -> | |
| {ok, Temperature, Timestamp}. | |
| to_nl(Binary) -> | |
| binary:split(Binary, <<10>>). | |
| path(Wire, Device) -> | |
| filename:join(["", "sys", "bus", Wire, "devices", Device, Wire ++ "_slave"]). | |
| get_temp() -> | |
| %% You'll need the devide id of your sensor as the second param | |
| Path = path("w1","28-0000044719d7"), | |
| Temp = case file:read_file(Path) of | |
| {ok, Binary} -> | |
| read(Binary); | |
| Else -> | |
| Else | |
| end, | |
| Temp. | |
| start() -> | |
| init(), | |
| io:format("blink test~n"), | |
| blink(), | |
| io:format("fetch temperature"), | |
| Temp = get_temp(), | |
| io:format("Temperature: ~p~n", [Temp]), | |
| %% Temp might not be correct - the YES/NO word in the first line. In which case you'll run it again | |
| %% io:format("fetch temperature"), | |
| %% Temp = get_temp(), | |
| %% io:format("Temperature: ~p~n", [Temp]), |
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